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In this study, hydrogen harvesting from fermentation of sugarcane bagasse (SCB) was promoted by maintaining synergism between sulfonated graphene (SGR) catalyst and paper mill sludge (PMS). The sulfonic acid (–SO 3 H) groups in the catalyst played a major role in destructing the β-1,4 glycosidic bonds of sugarcane bagasse, releasing readily biodegradable sugars into the fermentation medium. The cellulose, hemicellulose, and lignin conversion efficiency were improved by 127.5%, 495.0%, and 109.2%, respectively with 20 mgSGR/gVS catalyst addition, compared with the control samples. These values were also higher than those obtained by non-sulfonated graphene catalyst. The hydrogenation of sugarcane bagasse was maximized at a sulfonated graphene catalyst dosage of 60 mgSGR/gVS, providing the highest hydrogen harvesting of 4104 ± 321 mL. This was associated with an increase of the Proteobacteria phyla up to 52.0%, Firmicutes phyla to 13.9%, and Acinetobacter sp. to 39.8% compared with only 37.0%, 11.3% and 11.1% in the control assay respectively. Moreover, sulfonated graphene catalyst supplementation promoted the acetate fermentation reaction pathway by increasing the acetate/butyrate ratio up to 4.1. Nevertheless, elevating the catalyst dosage up to 120 mgSGR/gVS reduced the hydrogen harvesting (1190 ± 92 mL) due to the release of furfural (1.76 ± 0.02 g/L) in the fermentation cultures, deteriorating the microbes' internal composition and metabolism bioactivities. Finally maximizing the hydrogen productivity from sugarcane bagasse is feasible by incorporation of paper mill sludge and sulfonated graphene catalyst at dosage not exceeding 60 mgSGR/gVS. However, investigating the recyclability and disposal of digestate containing sulfonated graphene catalyst and the associated economic feasibility needs more attention in the future. [Display omitted] • Sugarcane bagasse was fermented by paper mill sludge supported on sulfonated graphene. • Synergism between paper mill sludge/sulfonated graphene improved bio-H 2 by 4.8 times. • Sulfonated graphene promoted acetate fermentation (HAc/HBu of 4.1) and inhibited HPr. • Acinetobacter degrading phenol increased by 3.6 folds with sulfonated graphene catalyst. • MolDock visualized H-bonding in hydrogenase protein/sulfonated graphene interaction. [ABSTRACT FROM AUTHOR]

Co 3 O 4 catalysts supported on paper-like stainless steel fibers (PSSF) were prepared by MOFs-templated (M) method and applied for catalytic combustion of isopropanol. Physicochemical properties of the as-synthesized Co 3 O 4 catalysts were investigated by SEM, EDS mapping, TEM, XRD, BET, XPS and H 2 -TPR, respectively. Characterization results of SEM and TEM shown that Co 3 O 4 (M)-350 and Co 3 O 4 (M)-400 still remained the dodecahedron shape of the ZIF-67 precursor and possessed porous structures. The XPS results shown that the ratio of Co3+/Co2+ and O c /O c ​+ ​O a ​+ ​O l firstly increased and then decreased with the increase of calcination temperature. Among the as-synthesized catalysts, Co 3 O 4 (M)-400 exhibited the highest activity for the catalytic combustion of isopropanol with the T 50 and T 90 values of 258 ​°C and 281 ​°C, respectively, which was associated with high BET surface area, high amount of Co3+ species and abundant surface chemisorbed oxygen. Moreover, Co 3 O 4 (M)-400 was employed as a structured catalyst for isopropanol combustion, the catalytic kinetics were studied based on different feed concentration, bed height and GHSV. The experimental results indicated that the T 50 and T 90 of isopropanol combustion over Co 3 O 4 (M)-400 with the bed height of 2 ​cm were increased slightly as the GHSV and feed concentration of isopropanol increased. Fig. 1 Preparation process and Catalytic performance of Catalysts. [Display omitted] • A novel gradient porous Co 3 O 4 (M)-X catalyst was prepared by MOFs-templated method. • The effect of preparation methods on properties of Co based catalysts were studied. • Co 3 O 4 (M)-400 shown the highest isopropanol catalytic combustion performance. [ABSTRACT FROM AUTHOR]

As a high-active metal-free electrocatalyst for NH 3 production via NO reduction reaction, honeycomb carbon nanofiber achieves an NH 3 yield of 22.35 μmol h−1 cm−2 with a high Faradaic efficiency of 88.33%. [Display omitted] Electrocatalytic NO reduction is a promising technology for ambient NO removal with simultaneous production of highly value-added NH 3. Herein, we report that honeycomb carbon nanofiber coated on carbon paper acts as an efficient metal-free catalyst for ambient electroreduction of NO to NH 3. In 0.2 M Na 2 SO 4 solution, such catalyst achieves an NH 3 yield of 22.35 μmol h−1 cm−2 with a high Faradaic efficiency of up to 88.33%. Impressively, it also shows excellent stability for 10-h continuous electrolysis. Theoretical calculations reveal that the most active center of functional groups is –OH group for NO reduction with a low energy barrier (ΔG of 0.29 eV) for the potential-determining step (*NO + H → *HNO). [ABSTRACT FROM AUTHOR]

In this paper, Fe-N 3 S 1 and FeS sub-nano cluster are innovatively connected to S, N co-doped carbon matrix (SNC) by controlled calcination process. The local electron configuration of Fe center is modulated by this unique structure. Based on this design, Fe-N 3 S 1 and FeS sub-nano cluster shown excellent synergistic effects in oxygen reduction reaction. The optimized ORR activity was obtained. [Display omitted] Single atomic Fe-N 4 catalyst exhibits a great prospect for oxygen reduction reaction (ORR) and adjusting the intrinsic coordination structure and the carbon matrix structure effectively improves the catalytic activity. However, controlling the active site coordination structure and its surrounding environment at atomic level remains a challenge. In this paper, Fe-N 3 S 1 and FeS sub-nano cluster were innovatively concatenated on S, N co-doped carbon matrix (SNC), denoted as FeS/FeSA@SNC catalysts, for modulating ORR catalysis performance. Both experimental measurements and theoretical calculations have confirmed that the local electron configuration of Fe center is modulated by this unique structure combination leading to optimized ORR kinetics. Based on this design, the synthesized FeS/FeSA@SNC delivers ORR activity with a half-wave potential of 0.9 V (vs. RHE), excelling that of commercial Pt/C (0.87 V) and the Zn-air battery (ZAB) with this cathode catalyst delivers a peak power density of 126 mW cm−2. This work presents a novel strategy for manipulating the single-atom active sites through control the local coordination structure and provides a reference for the development of novel efficient ORR electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • There is no reported work on 3D printed catalysts for biomass-biooil conversion applications. To fill this gap, this paper reviewed the key technologies that will be needed including 1) typical catalysts used for biomass conversion applications, 2) 3D printed catalysts, and 3) design and optimization of structured catalysts. • Desired catalysts performance in current biomass-biooil conversion research is mostly achieved by altering catalyst material composition rather than structural properties. • 3D printed catalysts research is still in its infancy and lacks full considerations of the design potentials of 3D printing, such as hierarchical complexity and material complexity. • Current work on design and optimization of structured catalysts shows deficiency in manufacturing constraints, for example, resolution of 3D printers, which may lead to coke formation issues in catalytic process. The devastative effects of traditional fossil fuel consumption have made biomass (e.g., plants, wood, and waste) a widely used renewable source of energy. The variety in biomass properties makes tunable catalysts an essential ingredient to promote reactions for desired molecule outputs. Catalysts with optimal catalytic performance are typically structured with complicated morphology, such as high porosity and sophistic pore network, which makes it challenging for catalyst fabrication. Recent progress in utilizing 3D printing as the fabrication method has demonstrated great potential of handling the complex structure while improving catalytic performance; however, rare work has focused on biomass-bio-oil conversion (BBC). With the aim of developing the optimal structured catalysts for BBC applications, this paper particularly reviewed 1) typical catalysts used for biomass conversion applications, 2) 3D printed catalysts, and 3) design and optimization of structured catalysts. It is found that the BBC is often isolated from manufacturing and focused more on different catalyst composition with transition metals to provide the desired catalyst architecture and further to improve upgrading of the BBC product. Current work on 3D-printed catalysts also show deficiency in several aspects including formation of coke and catalyst deactivation, lack of a comprehensive design for the catalyst structure (e.g., mostly 2D structures), absence of manufacturing constraints in design operation, and insufficient resolution of 3D printing methods. To solve these issues, several potential research directions and opportunities are discussed at the end of the study. [ABSTRACT FROM AUTHOR]

[Display omitted] • PtRu catalysts composed of Pt and RuO 2 are synthesized via cyclic electrodeposition. • PtRu catalyst shows unprecedented performance for ECH of phenol to cyclohexanol. • PtRu catalyst possesses outstanding reusability in acidic electrolyte. • The activation of phenol is observed via in situ Raman spectroscopy. • The direct reduction mechanism with proton-coupled electron transfer is proposed. Electrocatalytic hydrogenation (ECH) of phenol has been recognized as a promising route towards facile and green production of cyclohexanol. However, the practical application is hindered by product selectivity and catalyst durability. Herein, a series of PtRu electrocatalysts composed of metallic Pt0 and RuO 2 species are in situ fabricated on carbon paper via cyclic electrodeposition, showing outstanding activity and stability for ECH of phenol. At ambient temperature and a current density of 10 mA cm−2, the optimal Pt3Ru3 catalyst achieves a 100 % selectivity to cyclohexanol at a 100 % conversion of phenol in 0.1 M H 2 SO 4. At 100 mA cm−2, Pt3Ru3 achieves an outstanding faradaic efficiency of ∼87 % and a cyclohexanol production of 52.6 mg cm−2 h−1. Two parallel ECH pathways from phenol to cyclohexanol are identified. In situ Raman spectroscopy and kinetic study reveal that phenol could be hydrogenated over Pt3Ru3 in acidic electrolyte via proton-coupled electron transfer with the destruction of conjugated π bond of aromatic ring. This work offers an effective approach for facile construction of durable electrode material and an efficient electrochemical strategy for phenol hydrogenation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bifunctional catalyst Fe[ Pc (I) 4 ] + Ni[ Pc (I) 4 ]@NC PDI for ORR and OER is synthesized. • The NC PDI with 2D structure and superior stability was used as support. • Iodine groups in TM[ Pc (I) 4 ] creates a built-in electric field to enhance catalysis. • The synergistic effect of Fe[ Pc (I) 4 ]/Ni[ Pc (I) 4 ] enhances the catalytic performance. • The catalyst has superior performance for ORR/OER in rechargeable Zn-air batteries. In this paper, we report on the preparation and catalysis of a bifunctional molecular catalyst (Fe[ Pc (I) 4 ]+Ni[ Pc (I) 4 ]@NC PDI) for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable Zn-air batteries. This catalyst is prepared by self-assembling tetraiodo metal phthalocyanines (Fe[ Pc (I) 4 ] and Ni[ Pc (I) 4 ]) on a 2D N -doped carbon material (NC PDI) through π-π interactions. The introduction of iodine groups in the edge of phthalocyanines controls the density of electron cloud and electrostatic potential around Fe-N/Ni-N sites and constructs a built-in electric field that facilitates directional transport of charges, enhancing the catalytic activity of the catalyst. Density functional theory (DFT) calculations support this mechanism by showing a reduced energy barrier for the ORR rate-determining step (RDS). The Fe[ Pc (I) 4 ]+Ni[ Pc (I) 4 ]@NC PDI exhibits excellent performance outperforming 20 wt% Pt/C and single-molecule self-assembled Fe[ Pc (I) 4 ]@NC PDI and Ni[ Pc (I) 4 ]@NC PDI , with a half-wave potential of E 1/2 = 0.940 V in the ORR process under alkaline condition. During the OER process, Fe[ Pc (I) 4 ]+Ni[ Pc (I) 4 ]@NC PDI exhibited a low overpotential of 298 mV at 10 mA cm−2 under the alkaline condition, which is much better than RuO 2 , Fe[ Pc (I) 4 ]@NC PDI and Ni[ Pc (I) 4 ]@NC PDI. The catalyst also demonstrates excellent catalysis and durability in rechargeable Zn-air batteries. This work provides a simple and specific method to develop efficient multifunctional molecular electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption energies of CO 2 on the surface oxygen vacancies of different crystalline In 2 O 3 were calculated using DFT. • The effect of the spatial distributions of two active components on the CO 2 hydrogenation to aromatics was studied. • The acidity of catalyst under different spatial distributions was studied through NH 3 -TPD. In tandem catalysts, not only good synergy between the two active components is required, but also the precise control of the spatial distribution between the two active components of metal oxides and zeolite is crucial for the migration and conversion of reaction intermediates in the direct conversion of CO 2 to hydrocarbons. The correlation between the metal and the acidic site of zeolite has traditionally been simplified as "the closer, the better". However, it should be noted that this principle only holds true for a portion of tandem catalysts. Therefore, this paper studied the effect of different crystalline In 2 O 3 (cubic phase, hexagonal phase, and mixed cubic/hexagonal phase) and sheet HZSM-5 zeolite tandem catalysts on the activity of CO 2 hydrogenation reaction under different spatial distribution. The generalized gradient approximation (GGA) of density functional theory (DFT) were used to simulate the adsorption energy of CO 2 by oxygen vacancy on c-In 2 O 3 (1 1 1) and h-In 2 O 3 (1 0 4) planes, it was found that O v1 on c-In 2 O 3 (1 1 1) and O v4 on h-In 2 O 3 (1 0 4) had the strongest adsorption energy for CO 2. In addition, it has been observed that the proximity of the two active components (e.g., during mortar mixing) results in decreased catalytic performance. This is due to the migration of metal In, which neutralizes the acid sites of zeolites and leads to inefficient conversion of methanol reaction intermediates to aromatics. As a result, CO 2 conversion and aromatic selectivity are decreased. [ABSTRACT FROM AUTHOR]

[Display omitted] • Understanding the dynamic evolution of catalysts under reaction condition is critical to rational design of catalysts and control of catalytic properties, yet presents great challenges to both experimental and computational techniques. • Here we report an original study that aims to advance the fundemental understanding of the dynamic change of an supported Cu catalyst and the corresponding catalytic property during electrochemical reduction of CO 2 to ethanol by a comprehensive structural and mechanistic study. • This study integrates in-situ X-ray absorption near edge structure (XANES) spectroscopy with ab initio XANES simulations to identify the structural changes of the catalyst, combined with systematic density functional theory (DFT) caclulations of reaction mechanism on various catalytic sites. • The evolution of single-atom Cu to Cu nanoparticles under electrochemical condition has been identified, and Cu partcile size effect on activity and product selectivity is demonstrated. This work also demonstrates an effective strategy on studying the dynamic evolution of catalysts. Direct electrochemical conversion of CO 2 to ethanol (CH 3 CH 2 OH) offers a promising strategy to lower CO 2 emission while storing energy from renewable electricity. Our recent study reported a carbon-supported atomically dispersed Cu catalyst that achieved the highest reported selectivity for CH 3 CH 2 OH formation (91%) at a relatively low potential (-0.6 V), however, the active site structure that is responsible for such high activity and selectivity has yet to be understood. In this paper, we demonstrate a computational investigation combining X-ray absorption near edge structure (XANES) simulations and a mechanistic study via density functional theory (DFT) to understand the catalyst structures of this Cu catalyst during electrocatalysis and the corresponding reaction mechanisms of the key products. An integrated computational and experimental XANES analysis depicted the dynamic evolution of the catalytic site during electrocatalysis. The as-prepared, atomically dispersed Cu catalyst aggregates and forms metallic clusters/nanoparticles under electrochemical condition, which then break down to smaller oxidized clusters after electrocatalysis. The formed Cu clusters/nanoparticles showed distinct catalytic activity and selectivity as a function of particle size based on the mechanistic investigation using DFT, which is consistent with experimental observations for catalyst samples with different Cu loadings. This comprehensive study which combines experimental and computational XANES investigation, mechanistic study via DFT calculations, and experimental performance of the catalysts, provides unprecedented dynamic and mechanistic insights into the supported atomically dispersed metal catalysts for CO 2 reduction. Such strategy and details gained can further guide discovery of novel catalyst materials for CO 2 electrochemical reduction. [ABSTRACT FROM AUTHOR]

N -doped porous carbon monatomic iron catalysts (Fe SA /NPCs) obtained by polydopamine modification strategy were used for high efficiency oxygen reduction reactions and zinc-air batteries. [Display omitted] • Nitrogen doped porous carbon materials (NPCs) were prepared based on ZIF-L. • Stable hollow leaf-like morphology was maintained by coating PDA and nitrogen content was adjusted. • Fe SA was easily anchored on NPCs with luxuriant anchoring sites. • Fe SA /NPCs shows excellent electrochemical performance in oxygen reduction and zinc air batteries. Metal-nitrogen-carbon (M N C) catalysts, especially Fe N C catalysts, are considered promising candidates to replace Pt-based catalysts, but Fe N C catalysts still present certain challenges in controlled-synthesis and energy device applications. In this paper, through the modification strategy of poly-dopamine (PDA) to maintain 2D leaf morphology to obtain more active sites and further adjust the N content, N -doped porous carbon monatomic iron catalyst (Fe SA /NPCs) with rich-nitrogen content was prepared. XPS analysis showed that compared with C-ZIF-Fe, the contents of graphite nitrogen and pyridine nitrogen increased in Fe SA /NPCs. The hollow structure with defects and Fe-N 4 configuration of Fe single atom show more active sites for the catalyst, and positively promote the diffusion of reactants, oxygen exchange and electron transport, thus changing the reaction kinetics and promoting the improvement of ORR activity. Fe SA /NPCs electrocatalyst exhibits good half-wave potential and onset potential at low loading (E 1/2 = 0.93 V, E onset = 1.0 V). In addition, the methanol tolerance, stability and Tafel slope are better than those of commercial Pt/C. Excitingly, the zinc-air cell with Fe SA /NPCs as cathode material achieves a power density of 223 mW cm−2 and exhibits a long-term stability higher than 200 h. This work shows that nitrogen-doped porous carbon materials as well as iron monoatoms play important roles in improving electrocatalytic performance. [ABSTRACT FROM AUTHOR]

A novel single-atom Pt-CeO 2 /Co 3 O 4 catalyst with ultra-low Pt loading capacity (0.06 wt%) was fabricated. The sample presents better catalytic activity, stability and water resistance than the Pt nanoparticle supported catalysts. The excellent properties are attributed to the stronger metal-support interaction (SMSI) between single-atomic Pt and the support, which induces more Pt0, Ce3+ and Co3+ species to participate in the deep oxidation of toluene. [Display omitted] • Single-atom Pt-CeO 2 /Co 3 O 4 catalyst with ultra-low Pt loading (0.06 wt%) and excellent toluene oxidation activities (T 90 = 169 °C) was fabricated. • The ultra-long durability (120 h) of the 0.06Pt-SA was superior to most noble metal single-atomic catalysts reported so far. • Enhanced metal support interaction between single atomic Pt and CeO 2 -Co 3 O 4 carrier induced more Pt0, Ce3+ for oxygen activation and more Co3+ for toluene activation. The design and manufacture of high activity and thermal stability catalysts with minimal precious metal loading is essential for deep degradation of volatile organic compounds (VOCs). In this paper, a novel single-atom Pt-CeO 2 /Co 3 O 4 catalyst with ultra-low Pt loading capacity (0.06 wt%, denoted as 0.06Pt-SA) was fabricated via one-step co-precipitation method. The 0.06Pt-SA exhibited excellent toluene degradation activity of T 90 = 169 °C, matched with the nanoparticle Pt-supported CeO 2 /Co 3 O 4 catalyst with more than six times higher Pt loading (0.41 wt%, denoted as 0.41Pt-NP). Moreover, the ultra-long durability (toluene conversion remains 99% after 120 h stability test) and excellent toluene degradation ability in a wide space speed range of 0.06Pt-SA were superior to that of 0.41Pt-NP catalyst. The excellent performance was derived from the strong metal-support interaction (SMSI) between the single atomic Pt and the carrier, which induced more Pt0 and Ce3+ for oxygen activation and more Co3+ for toluene removal. The in situ diffuse reflectance infrared spectroscopy (DRIFTS) experiments confirmed that the conversion of intermediates was accelerated in the reaction process, thereby promoting the toluene degradation. Our results should inspire the exploitation of noble single-atomic modification strategy for developing the low cost and high performance VOCs catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing efficient and durable bifunctional air–cathode catalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is one of the key efforts promoting the practical rechargeable zinc-air batteries (ZABs). In this paper, high-performance bifunctional air–cathode catalysts by a two-step strategy: atomically dispersed Ni on N -doped carbon is first derived from MOF to form uniformly dispersed NiNC, which are pyrolyzed together with Fe source at different high-temperatures to form FeNi@NC-T (T = 800, 900, and 1000 °C) catalysts. The as-synthesized non-noble metal FeNi@NC-900 catalyst exhibits a considerably small potential gap (ΔE) of 0.72 V between ORR and OER, which is as the same as commercial noble metal Pt/C + Ir black mixed catalyst. The performance of the ZABs using FeNi@NC-900 as the air–cathode catalyst displays a power density of 119 mW·cm−2 and a specific capacity of 830.1 mAh·g−1, which is superior to that of Pt/C + Ir black mixed catalyst. This work provides a guideline for designing alloy electrocatalysts with uniform size and nanoparticle distribution for metal-air batteries with bifunctional air-cathodes. [ABSTRACT FROM AUTHOR]

On the international level, it is common to act on reducing emissions from energy systems. However, in addition to industrial emissions, low-stack emissions also make a significant contribution. A good step in reducing its environmental impact, is to move to biofuels, including biomass. This paper examines the impact of placing a catalytic system in a retort boiler to minimize emissions of greenhouse gases, dust and other pollutants when burning pellets. The effect of platinum, and oxides of selected metals placed on the deflector as a solid catalyst was studied. Based on the experimental data, a branched artificial neural network was constructed and trained. The routing of three parallel topologies made it possible to achieve high accuracy while keeping the input data relatively simple. The system showed an average error of 3.54% against arbitrary test data. On the basis of experimental data as well as predictions returned by the artificial neural network, recommendations were shown for the catalysts used and their amounts. Depending on the biomass from which the pellet was produced, the experiment suggested the use of titanium or copper oxides. In the case of the neural network, it was able to select a better system, based on platinum, improving emission reductions by up to more than 19%, depending on the type of pellet used. [Display omitted] • Unique three-path-ANN system to simulate catalytic biomass combustion. • High accuracy with MRE of 3.54 % versus unbiased test data. • Bioenergy production from straw, hemp and wood pellets. • Complexed system to forecast 11 different parameters. • Case study indicates optimal catalyst – feedstock pairs. [ABSTRACT FROM AUTHOR]

Photocatalytic Hydrogen production as one of the effective ways to solve the future energy issues has recently become a research hotspot in the field of renewable energy. However, single-component photocatalysts have poor hydrogen production efficiency due to the narrow light-absorption range, susceptibility to photo-corrosion and low catalytic activity. Herein, novel heterojunction photocatalysts of ZnIn 2 S 4 @BiYWO 6 with different mass ratios were designed and synthesized using a facile two-step hydrothermal method. Experimental results and analyses show that these heterojunction catalysts exhibit extremely excellent photocatalytic performance for hydrogen production. Especially, the hydrogen production rate of 10ZnIn 2 S 4 -BiYWO 6 is 73 times higher than that of pure ZnIn 2 S 4. Furthermore, enhanced photocatalytic mechanism and carrier transfer pathway in the heterojunction photocatalyst of ZnIn 2 S 4 @BiYWO 6 were deeply analyzed and explored in the paper, which confirmed that ZnIn 2 S 4 @BiYWO 6 is a direct Z-scheme heterojunction architecture. Within such a Z-scheme framework, the presence of a built-in electric field at the interface between ZnIn 2 S 4 and BiYWO 6 as well as the energy band bending lead to the direct recombination of electrons and holes with low redox capacity, while keeping the electrons and holes with high redox capacity in each component. Consequently, the photocatalytic activity of the Z-scheme heterojunction system has been greatly enhanced. It is believed that the present work provides valuable guidance for the design and construction of novel Z-scheme heterojunction photocatalysts. Z-scheme heterojunctions greatly enhanced photocatalytic hydrogen production efficiency of ZnIn 2 S 4 @BiYWO 6 composites. [Display omitted] • ZnIn 2 S 4 @BiYWO 6 photocatalysts exhibit excellent hydrogen production efficiency. • Z-scheme heterostructures play a key role in enhancing photocatalytic activity. • Such Z-scheme photocatalysts are promising for photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

[Display omitted] As a renewable green energy, hydrogen has received widespread attention due to its huge potential in solving energy shortages and environment pollution. In this paper, a one-step solvothermal method was applied to grow ultra-thin g-C 3 N 4 (UCN) nanosheets and NiS nanoparticles on the surface of ZnIn 2 S 4 (ZIS). A ternary NiS/ZnIn 2 S 4 /ultra-thin-g-C 3 N 4 composite material with dual high-speed charge transfer channels was constructed for the advancement of the photocatalytic H 2 generation. The optimal ternary catalyst 1.5wt.%NiS/ZnIn 2 S 4 /ultra-thin-g-C 3 N 4 (NiS/ZIS/UCN) achieved a H 2 evolution yield reached to 5.02 mmolg−1h−1, which was 5.23 times superior than that of pristine ZnIn 2 S 4 (0.96 mmolg−1h−1) and even outperform than that of the best precious metal modified 3.0 wt%Pt/ZnIn 2 S 4 (4.08 mmolg−1h−1). The AQY at 420 nm could be achieved as high as 30.5%. The increased photocatalytic performance of NiS/ZIS/UCN could be ascribed to the type-I heterojunctions between intimated ZIS and UCN. In addition, NiS co-catalyst with large quantity of H 2 evolution sites, could result in efficient photo-induced charges separation and migration. Furthermore, the NiS/ZIS/UCN composite exhibited excellent H 2 evolution stability and recyclability. This work would also offer a reference for the design and synthesis of ternary co-catalyst with heterojunction composite for green energy conversion. [ABSTRACT FROM AUTHOR]

Schematic diagram of fabricating process of NixSey/MoSe2/NF hollow rod arrays. [Display omitted] Alkaline water electrocatalysis is considered as one of the most reliable method to prepare the stable, inexpensive, and sustainable water splitting catalyst in large-scale. Recently, MoSe 2 attracted great attention as a promising catalyst because of its high electrochemical activity and earth-abundant nature. In this paper, bionic Ni x Se y /MoSe 2 coralline-liked heterogeneous structures were successfully prepared on 3D nickel foam (NF) via a simple solvothermal process complemented by hydrothermal strategy with selenization and alkali treatment. Furthermore, to overcome the less active sites and poor electrical conductivity of MoSe 2 , we learned from the coral structure for the inspiration, and reported a novel hollow rod-like structure with increased active sites. Also, 1 T-2H MoSe 2 improved the electrical conductivity of single phase MoSe 2. We first confirmed the multi-phase of catalyst by XPS analysis with Mo 3d 5/2 splited into two independent regions with the 2H and 1 T phase transition. The optimal ratio of Ni x Se y/ MoSe 2 /NF-5 exhibited excellent electrocatalytic activity towards HER in 1 M KOH, driving current densities of 10, 100 and 200 mA cm−2 at only 76, 165 and 194 mV with stability over 24 h. The work provides new ideas for the construction of transition metal selenides hollow rod array structures of efficient HER electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] As a promising dopant, electron deficient B atom not only tunes the electronic structure of electrocatalysts for improving their intrinsic catalytic activities, but also combines with hydroxy radical as strong adsorption sites for accelerating the water dissociation during the hydrogen evolution reaction (HER). In this paper, we report an electrocatalyst based on boron-modified Ru anchored on carbon nanotubes (B-Ru@CNT) that shows impressive HER activity in acidic and alkaline media. The boron-rich closo -[B 12 H 12 ]2- borane was selected as a moderately strong reductant for the in situ reduction of a Ru salt, which yielded B-doped Ru nanoparticles. The experimental and theoretical results indicate that the incorporation of B not only weakens the Ru-H bond and downshifts the d-bond centre of Ru from the Fermi level by reducing the electron density at Ru but also accelerates the water dissociation reaction by providing B sites, which strongly adsorb OH* intermediates, and nearby Ru sites, which act as sites for the adsorption of the H* intermediate, thus boosting the HER performance and enhancing the HER kinetics. As a result of the tuning of the electronic structure via B doping, B-Ru@CNT showed excellent HER performance, yielding overpotentials of 17 and 62 mV at a current density of 10 mA cm−2 in alkaline and acidic solutions, respectively. These results indicate that our synthetic method is a promising route to B-doped metallic Ru with enhanced pH-independent HER performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • WN nanosheets were prepared by sol–gel method. • CdS/WN was prepared by one pot solvothermal method. • Intimate interfacial contact between CdS NPs and WN engenders Schottk junction. • The evolution rate of optimal CdS/WN H 2 was 9.28 times that of CdS NPS. Based on the strategy that electrocatalysts can be used as additives to improve the performance of photocatalysts, and the unique metalloid properties of tungsten nitride (WN), it can form a Schottky junction with the semiconductor at the heterogeneous interface to improve the photocatalytic performance of semiconductor catalysts. In this paper, WN with excellent electrical conductivity was selected as a new noble-metal-free co-catalyst to improve the photoreduction hydrogen (H 2) evolution performance of CdS nanoparticles (NPs). Firstly, WN nanosheets were prepared by sol–gel method; then, a novel and noble-metal-free heterojunction photocatalyst, which is CdS NPs deposited on the surface of WN, was successfully fabricated via one-pot solvothermal method. Under visible light irradiation, the H 2 production rate of the WN/CdS composite catalyst is 24.13 mmol/g/h, which is 9.28 times that of pure CdS NPs. The observably boosted H 2 generation activity could be ascribed to the broadened visible-light absorption and intimate interfacial contact between CdS NPs and WN engenders Schottky junction. This study provides a novel and cost-effective approach for designing efficient noble-metal-free photocatalysts and improving H 2 evolution activity of CdS under visible-light-driven photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] • The flooding of GDEs used for CO 2 electrolysis causes unstable electrolyser behavior and, with time, the loss of Faradaic efficiency for CO production. • Flooding is closely related to the formation of potassium carbonate and bicarbonate salts in the GDE structure that causes hydrophobicity loss. • The cross-sectional elemental (K) mapping of GDEs by EDX helps the visualization of K salt penetration inside a GDE structure, but does not allow quantitative comparison. • By combining EDX mapping with ICP-MS based total K content determination, quantitative and comparable depth profiles can be obtained. • The combined EDX/ICP-MS approach is used to study two different GDLs: one with a cracked, and another with a compact microporous layer. • The analysis indicates better water management for the cracked GDL. The most promising strategy to scale up the electrochemical CO 2 reduction reaction (ec - CO 2 RR) is based on the use of gas diffusion electrodes (GDEs) that allow current densities close to the range of 1 A/cm2 to be reached. At such high current densities, however, the flooding of the GDE cathode is often observed in CO 2 electrolysers. Flooding hinders the access of CO 2 to the catalyst, and by thus leaving space for (unwanted) hydrogen evolution, it usually leads to a decrease of the observable Faradaic efficiency of CO 2 reduction products. To avoid flooding as much as possible has thus become one of the most important aims of to-date ec - CO 2 RR engineering, and robust analytical methods that can quantitatively assess flooding are now in demand. As flooding is very closely related to the formation of carbonate salts within the GDE structure, in this paper we use alkali (in particular, potassium) carbonates as a tracer of flooding. We present a novel analytical approach —based on the combination of cross-sectional energy-dispersive X-ray (EDX) mapping and inductively coupled plasma mass spectrometry (ICP–MS) analysis— that can not only visualise, but can also quantitatively describe the electrolysis time dependent flooding in GDEs, leading to a better understanding of electrolyser malfunctions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Propene oxidation and ammoxidation are both initiated by C H bond activation. • Mo O bonds interacting with Bi cations are the active centers for C H activation. • Bi3+ cations adsorb both propene and ammonia for propene ammoxidation. • Allyl amine is a critical intermediate in the formation of acrylonitrile. • The activation energy for formation of allyl amine is lower than to acrolein. Robert K. Grasselli was a pioneer in the development and commercialization of catalysts for propene oxidation to acrolein and ammoxidation to acrylonitrile, products that today are produced at the level of over 10 billion pounds per year. The catalysts used for both processes are contain bismuth molybdates augmented by up to seven additional elements used to attain high activity, selectivity, and stability. The importance of propene oxidation and ammoxidation has stimulated considerable interest in understanding the mechanism and kinetics of these processes and the particular role of catalyst composition and structure in defining catalyst activity and selectivity. Virtually all of this work has been carried out using bismuth molybdates, primarily α-Bi 2 Mo 3 O 12. The objective of this paper is to review the findings of experimental studies and illustrate how theoretical studies based on density functional theory provide additional insights that support deductions drawn from experiments and, more importantly, provide information that cannot be accessed experimentally. [ABSTRACT FROM AUTHOR]

The development of highly efficient and low-cost bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key to the industrialization of large-scale hydrogen production, while the development of non-precious-metal catalysts that can be substituted for precious-metal materials is the current trend of research. In this paper, nickel foam (NF) self-supported CoFe layered bimetallic hydroxide (LDH)-CuCo 2 S 4 electrocatalysts were prepared using a simple hydrothermal and electrodeposition method. The prepared CuCo 2 S 4 @CoFe-LDH/NF catalysts showed good performance in alkaline water oxidation, proton reduction and overall water decomposition with an overpotential of 293 mV for the oxygen evolution reaction (OER) at a current density of 50 mA cm−2 and 63 mV for the hydrogen evolution reaction (HER) at a current density of 10 mA cm−2. When CuCo 2 S 4 @CoFe-LDH/NF was used as a bifunctional electrocatalyst for the decomposition of water, the voltage of the 10 mA cm−2 electrolyzer was only 1.54 V, and the stability of the electrolyzer reached 60 h, which was superior to other bifunctional catalysts. [Display omitted] • CoCu-LDH grows firmly on nickel foam by a hydrothermal method. • Vulcanization at room temperature makes the experimental conditions milder and simpler. • An electrodeposition method was used to grow nanosheets on nanowires. [ABSTRACT FROM AUTHOR]

The developed simple mesoporous Ar-G-CM/SiO 2 composite with multiple hydrogen bond donor groups presented good to excellent catalytic activity to the CO 2 cycloaddition with various epoxides under metal-absent and solvent-free conditions. [Display omitted] • TAr-G-CM/SiO 2 catalyst presented efficient catalysis for CO 2 cycloaddition. • The efficient catalysis was originated from HBD groups and mesoporous structure. • The synthesis for catalyst was a green route without toxic solvent use. In this paper, a novel arginine-glucose derived carbonaceous-material-loaded SiO 2 composite catalyst (Ar-G-CM/SiO 2) was synthesized from non-toxic and harmless reagents (arginine, glucose and tetraethylorthosilicate) by simple hydrothermal process. Mesoporous SiO 2 with high specific area served as support for carbonaceous material and provided extra hydrogen bond donor (HBD) groups. Ar-G-CM/SiO 2 with acid-base dual functional groups (COOH, NH 2) and HBD group (OH) presented 62% yield and 99% selectivity to product of propylene carbonate in CO 2 cycloaddition reaction with propylene oxide even at 40 °C, 2 MPa under metal-absent and solvent-free conditions. For some less active epoxides with steric hindrance, Ar-G-CM/SiO 2 also showed good yield and selectivity over 90% by raising temperature to 120 °C. Furthermore, the Ar-G-CM/SiO 2 catalyst could be reused for six successive cycles without significant decrease in catalytic activity or structural deterioration, because the carbon deposition was restrained owing to the mesoporous structure of the catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • The surface properties CeO 2 with different exposed facets were investigated. • CeO 2 surface lattice oxygen were found important for Pt sintering-resistance. • The effects of ageing and reduction conditions on activities were elucidated. Propane (C 3 H 8) is one of the gases hardest to convert in vehicles' exhausts, which largely affects the emission control ability of after-treatment systems. In this paper, we take Pt-CeO 2 catalysts as an example to investigate the supports' facet-depended propane oxidation performance. Four types of CeO 2 materials with different morphologies (nano-lamella, nano-cube, nano-polyhedron and nano-rod) were synthesized and were found to expose different dominating facets. Consequently, the nano-lamellar CeO 2 , mainly exposed (1 1 0) facet, delivered the best catalytic activity among various Pt-CeO 2 catalysts. The ageing and reduction pretreatments tuned the amount of oxygen vacancies and Pt size/Pt charge which remarkably affected the performances of Pt-CeO 2 catalysts. Based on the experiments and DFT calculations, it was concluded that oxygen on CeO 2 (1 0 0) surface was easily removed in reduction atmosphere leading to electron-rich Pt formed on oxygen absent (1 0 0) surface, while on CeO 2 (1 1 0) surface abundant oxygen vacancies were generated during reduction pretreatment and additional surface lattice oxygen contributed to form electron-deficient Pt kept in small cluster size. This research will help us to develop more efficient exhaust catalysts through a deep understanding of the electronic interactions between the metal and active surface of supports. [ABSTRACT FROM AUTHOR]

[Display omitted] In this paper, sulfated ZrO 2 were synthesized via precipitation and impregnation method, and the promoting effects of support sulfation on selective catalytic reduction (SCR) performance of CeO 2 /ZrO 2 catalysts were investigated. The results revealed that sulfated ZrO 2 could significantly enhance the SCR activity of CeO 2 /ZrO 2 catalysts in a wide temperature range. Especially when S/Zr molar ratio was 0.1, CeO 2 /ZrO 2 -0.1S catalyst exhibited a large operating temperature window of 251 ∼ 500 °C and its N 2 selectivity was 100 % in the temperature range of 150 ∼ 500 °C. Moreover, CeO 2 /ZrO 2 -0.1S catalyst possessed a superior low-temperature activity over 0.1S-CeO 2 /ZrO 2 catalyst. After exposing to 100 ppm SO 2 for 15 h, a high NO conversion efficiency of CeO 2 /ZrO 2 -0.1S catalyst (90.7 %) could still be reached. The characterization results indicated that ZrO 2 treated with a proper dosage of sulfate acid was beneficial to enlarge the specific surface area greatly. Sulfated ZrO 2 was also in favor of promoting the transformation of CeO 2 from crystalline state to highly-dispersed amorphous state, and inhibiting the transformation of ZrO 2 from tetragonal to monoclinic phase. It could also enhance the total surface acidity greatly with an increase in both Brønsted acid sites and Lewis acid sites, thus significantly improving NH 3 adsorption on catalyst surface. Besides, the promoting effect of support sulfation on SCR performance of CeO 2 /ZrO 2 catalysts was also related with the enhanced redox property, higher Ce3+/(Ce3++Ce4+) ratio and abundant surface chemisorbed labile oxygen. The in-situ DRIFTS results implied that nitrate species coordinated on the surface of CeO 2 /ZrO 2 -0.1S catalyst could participate in the Selective catalytic reduction with ammonia (NH 3 -SCR) reactions at either medium or high temperature, suggesting that both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms might be followed in SCR reactions. [ABSTRACT FROM AUTHOR]

Nanofirework-like PtRu alloy catalyst has been successfully synthesized and used as an efficient anodic catalyst for glycerol oxidation reaction (GOR) in alkaline medium. [Display omitted] • A class of firework-like bimetallic PtRu alloy nanocatalysts has been successfully fabricated. • The addition of Ru can effectively tune the electronic structure of Pt and greatly improve the performance of the catalyst. • The electrocatalytic properties of bimetallic PtRu catalysts strongly rely on their chemical composition. Electro-oxidation of glycerol is a key anodic reaction in direct alcohol fuel cell (DAFCs). Exploring the cost-effective nanocatalysts for glycerol oxidation reaction (GOR) is very important for the development of DAFC, but it is still challenging. In this paper, nanofirework-like PtRu alloy catalyst was successfully synthesized and used for GOR in alkaline medium. Thanks to the unique nanofirework-like structure and synergetic effects, the activity and stability of the as-prepared PtRu alloy nanofireworks (NFs) toward GOR were significantly improved relative to Pt NFs. In particular, the peak current density of GOR catalyzed by the optimized Pt 1 Ru 3 NFs catalyst reached 2412.0 mA mg−1, surpassing that of commercial Pt/C catalyst. This work has important guidance for the design of advanced anode electrocatalysts for fuel cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Generalized two-step reaction schemes for studying chemical kinetics on catalyst surfaces. • Analytical expressions derived for surface coverages, reaction rates and degree of rate control for associative and dissociative reaction mechanisms. • Analytical expression derived for determining surface properties of optimal catalysts. • Application of generalized two-step reaction schemes in understanding response of a catalyst surface to transient reaction conditions. Chemical reaction kinetics for steady-state catalytic reactions on heterogeneous catalysts are generally governed by a limited number of elementary steps and the nature of these steps is controlled by the degree of rate control and the surface coverage of reaction intermediates. The generalized two-step reaction scheme, first proposed by Michel Boudart, is used in this paper to drive analytical expressions for the surface coverages by the Most Abundant Reactive Intermediate (MARI); the surface coverage by the Most Abundant Surface Intermediate (MASI); the fraction of the free surface; the degree of rate control for each kinetically significant step; and the overall reaction rate. The two most ubiquitous reaction mechanisms in heterogeneous catalysis, i.e., the associative reaction mechanism and the dissociative reaction mechanism are studied. The applicability of the derived expressions is demonstrated by two case studies: acetone hydrogenation for the associative case and ammonia synthesis for the dissociative case. Scaling relations and BEP correlation are incorporated in the generalized two-step reaction scheme to determine the surface properties of the optimal catalyst. Acetone hydrogenation is used as a case study to demonstrate the applicability of the derived expressions for optimal catalyst. Finally, the application of generalized two-step reaction schemes in understanding the response of a catalyst surface to transient reaction conditions is discussed. Transient reaction kinetics of acetone hydrogenation is used as a case study to demonstrate the applicability of the generalized two-step reaction approach. [ABSTRACT FROM AUTHOR]

[Display omitted] • A micro-kinetic model was constructed for the ethylene oligomerization. • Hexene is formed via a series of ethylene coordination-insertion steps. • Octene is formed via co-oligomerization of ethylene and desorbed butene. We report the kinetics of ethylene oligomerization over the Ni-H-Beta for temperatures ranging between 50 and 100 °C and pressures ranging between 5 and 28 atm. According to our results, the apparent activation energies involved in the formation of butene, hexene, and octene are 44, 78, and 60 kJ.mol−1, respectively. The measured lower apparent activation energy for butene formation relative to hexene and octene is a likely result of the fact that the measured butene formation is not the true (forward) rate of formation of butene but it the net rate because of the consumption of butene in secondary reactions. Analysis of the reaction order indicates that participation of butene in chain-growth reactions takes place via desorption followed by re-adsorption of butene on the catalyst. The results also indicate that hexene undergoes a similar process. In the present paper, we refer to the pathway involving co-oligomerization of butene and hexene as "cascade co-oligomerization". Based on these findings, we proposed a reaction network and modeled reaction rate expressions for ethylene consumption and butene, hexene, and octene formation based on the construction of a micro-kinetic model. We calculated the kinetic parameters involved in the reaction network proposed and found evidence that the formation of octene proceeds mainly via the "cascade co-oligomerization" of re-adsorbed butene with ethylene. [ABSTRACT FROM AUTHOR]

This paper reports the usage ratio of TEOS and Zr(OBu) 4 on the formation of Ni@ZrO 2 yolk-shell for dry reforming of methane. From XPS analysis, the ZrO 2 hollow shell texture is demonstrated to be [TEOS]/[Zr(OBu) 4 ] dependent due to different sizes of SiO 2 produced. It found that an adequate ratio of [TEOS]/[Zr(OBu) 4 ] improves the catalytic conversion of dry reforming of methane. It (Ni@ZrO 2 -SiZr-7.7) shows 90% conversion for CH 4 and 93% for CO 2 at a WHSV of 72,000 mLg cat −1h−1 for 50 h at 800 °C with TOF CH4 of 8.7 s−1. It proposed that the changes in surface Si/Zr and gradual interconnecting pores contributed to its activity and stability. These finding's potential to be utilized in other high-temperature reactions. [ABSTRACT FROM AUTHOR]

The irreplaceable silicone materials among the high-tech industry is dimethyldichlorosilane, a monomer whose by-products generated in the synthesis step can be recycled through disproportionation reactions. In this paper, the catalytic activities of NH 2 -MIL-53(Al)@γ-Al 2 O 3 with Brønsted acid active sites and AlCl 3 /NH 2 -MIL-53(Al)@γ-Al 2 O 3 core-shell catalysts with Lewis acid active sites were investigated and compared for the disproportionation to prepare dimethyldichlorosilane by means of the M06-2X/Def2-TZVP hybrid functional method. The results given for structure, energy, vibrational frequency, IRC values, bond order, ELF and LOL analysis were matched. The results showed that AlCl 3 /NH 2 -MIL-53(Al)@γ-Al 2 O 3 core-shell catalyst with Lewis acid was more active. Simulated synthesis and interatomic correlation parameters (bond length/nm and bong angle/o) of NH 2 -MIL-53(Al)@γ-Al 2 O 3 (Cat. ,active site No.1-3) and AlCl 3 /NH 2 -MIL-53(Al)@γ-Al 2 O 3 (Cat.&, Configuration a-d). [Display omitted] • Proposed four- and six-step disproportionation allows recycling of (CH 3) 3 SiCl and CH 3 SiCl 3. • Loading of AlCl 3 presents Lewis catalytic centers, which possess enhanced catalytic activity compared to Brønsted acid. • Optimization of MOFs-based catalysts with core-shell structure, NH 2 -MIL-53(Al)@γ-Al 2 O 3 and AlCl 3 /NH 2 -MIL-53(Al)@γ-Al 2 O 3. [ABSTRACT FROM AUTHOR]

[Display omitted] • Atomically dispersed Ru/Mg-CeO 2 catalyst was prepared and possessed excellent catalytic performance for photo-thermal catalytic CO 2 methanation reaction. • The photo-electron excitation/migration path and the surface structure changes induced by light were systematically characterized by operando experiments. • All potential micro-reaction steps and light intensification steps were determined by in situ DRIFTs experiments. • The reversible dynamic structural evolution between Ru-O-Ce structure and Ru-O v -Ce structure could be induced by light. It is a promising green technology to reduce CO 2 to CH 4 by using renewable solar energy driving photo-thermal catalysis route. However, the efficiency of photo-thermal catalytic CO2 methanation remained to be improved, and the mechanism of this reaction still required further investigation. In this paper, a Ru/Mg-CeO 2 catalyst was designed based on the concepts of single atom catalyst and photo-thermal catalysis concept. The catalyst achieved the CH 4 formation rate of 469 mmol·gcat−1·h−1 at 400 °C under photo-thermal conditions with good catalytic stability. Besides, the superiority of the single-atom of Ru, Ru-O-Ce structure and doping of alkaline metals in catalytic process was proved by a series of physicochemical and optical characterization, and electron migration direction from Ce and Mg elements to Ru sites through Ru-O-Ce and Ru-O-Mg path under photo-thermal catalysis was determined by ISI-XPS experiment. Finally, the comprehensive reaction mechanism and reversible dynamic structural evolution process between Ru-O-Ce and Ru-O v -Ce structures were investigated by in situ DRIFTs experiments, and the source of the excellent performance and structure-function relationship of the catalyst was explored, which provided the theoretical and practical basis for the development of catalyst and industrial application of the reaction. [ABSTRACT FROM AUTHOR]

Developing an effective photocatalytic denitrification technology for NO 3 − and NO 2 − in water is urgently needed. In this paper, we synthesized a nitrogen-rich g-C 3 N 4 , and in-situ grown AgPd nanowires (NWs) on the surface of nitrogen-rich g-C 3 N 4 to build Ag y Pd 10−y /g-C x N 4 Mott-Schottky heterojunction. Compared with g-C x N 4 , Ag y Pd 10−y /g-C x N 4 exhibits the enhanced photocatalytic hydrogen production from water and tandem reduction of NO 3 − and NO 2 − without the addition of other hydrogen source under 365 nm irradiation. The catalytic activity and selectivity of Ag y Pd 10−y /g-C x N 4 were studied by combination of the nitrogen-rich g-C 3 N 4 and the different component of Ag y Pd 10−y nanowires (NWs). Among the Ag y Pd 10−y /g-C x N 4 catalyst, the Ag 3 Pd 7 /g-C 1.95 N 4 catalyst exhibited the highest photocatalytic activity and selectivity for photocatalytic reduction of NO 3 − and NO 2 −, and the removal rate of NO 3 − and NO 2 − are 87.4% and 61.8% under 365 nm irradiation at 25 °C, respectively. The strategy opens a new way for making the photocatalytic hydrogen production in tandem with reduction of NO 3 − and NO 2 − in water, also extending it to remove metal ion. [ABSTRACT FROM AUTHOR]

• Ni@Pd/C and Ni@PdRh/C core–shell nanoparticles were synthesized. • Catalytic activity toward ethanol oxidation depends on structure and composition. • The addition of Rh improves the catalytic activity and stability of Ni@Pd/C. • Ni@PdRh/C exhibited the highest catalytic activity for ethanol electro-oxidation. • The catalytic activity for Ni@PdRh/C was three times higher, compared to Pd/C. This paper describes the synthesis and catalytic activity of carbon-supported Pd/C, PdNi/C, and PdNiRh/C catalysts with core–shell morphologies towards the oxidation of ethanol in alkaline media. The catalysts are synthesised by a chemical reduction method using sodium borohydride as the reducing agent. Electrochemical characterisations show that the addition of Ni and Rh enhances remarkably the electrocatalytic activity of the materials due to the bifunctional and electronic effects in PdNi/C and PdNiRh/C catalysts, and the synergetic effect of the bifunctional and core–shell morphology on the Ni@Pd/C and Ni@PdRh/C catalysts. Electrochemical impedance spectra reveal lower values of charge transfer resistance for Pd 60 Ni 20 Rh 20 /C and Ni 20 @Pd 60 Rh 20 /C. Chronoamperometric tests also reveal the Ni 20 @Pd 60 Rh 20 /C catalyst displays current densities 9.3 times higher than the Pd/C catalyst. The superior catalytic performance of the trimetallic core–shell Ni 20 @Pd 60 Rh 20 /C catalyst can result from the synergy between the metals and the presence of core–shell morphology. [ABSTRACT FROM AUTHOR]

Bio-derived carbon-based metal-free ORR electrocatalyst prepared via solvent-free processing is superior to benchmark Pt/C catalyst in ORR activity, kinetics and durability across a wide pH range from alkalinity through neutrality to acidity. Metal-free carbons as durable high-performance oxygen reduction electrocatalysts, deemed to be promising alternatives to the platinum-group metals (PGMs), are vital to large-scale commercialization of fuel cells. Herein, a solvent-free synthetic strategy has been proposed to prepare N -doped nanoporous metal-free carbonaceous materials originating from various types of plant residues (papaya skin – fruit , bamboo shoot – forestry , wheat straw – farming and cabbage stem – vegetable). The optimal metal-free carbon, possessing maximized reaction surface area and optimized distributions of nanopore structures and nitrogen species, can function as the durable high-performance pH-universal ORR electrocatalyst, reaching or surpassing the benchmark 20% Pt/C catalyst within the wide scope of pH. This paper substantiates the solvent-free, scalable and bio-universal preparation approach to converting various biomass wastes into durable high-performance pH-universal ORR carbonaceous catalysts, capable of expanding the repertoire of cathode catalysts employed by fuel cells that demand diverse pH environments. [ABSTRACT FROM AUTHOR]

• Mn-promoted Ni catalysts on silica-modified alumina (SA) prepared. • Increasing Mn/Ni ratio yields more active and stable methanation catalysts. • Ni/SA methanation performance promoted by MnO at 1 bar and 20 bar. • Mn addition improves Ni reducibility and dispersion, CO 2 adsorption and activation. • Mn present as MnO clusters on Ni active phase in reduced catalysts. The viability of the Power-to-Gas (PtG) concept is strongly dependent on the development of highly active and stable methanation catalysts obtained from cheap and abundant elements. In this paper, the promotional effect of MnO on Ni catalysts supported on silica-modified γ-Al 2 O 3 (SA) was investigated in CO 2 and CO methanation on catalysts with Mn/Ni atomic ratios between 0 and 0.25. Significantly higher methanation rates and CH 4 selectivities were obtained for Mn-promoted compositions compared to Ni-only catalysts. The optimal NiMn/SA (Mn/Ni = 0.25) catalyst exhibited improved stability compared with unpromoted Ni/SA at 20 bar. The nature of the catalyst precursor and active catalyst was studied with STEM-EDX, XPS, and X-ray absorption spectroscopy (XAS). Evidence of a mixed Ni-Mn oxide in the catalyst precursor was obtained by EXAFS. EXAFS measurements revealed that the reduced catalyst consisted of metallic Ni particles and small oxidic Mn2+ species. Moreover, Mn addition improved the Ni dispersion and enhanced the Ni2+ reducibility by weakening the interaction between the Ni-oxide precursor and the support. A mechanistic study involving IR spectroscopy and steady-state isotopic (13CO 2) transient kinetic analysis (SSITKA) showed that the presence of Mn enhanced CO 2 adsorption and activation. [ABSTRACT FROM AUTHOR]

• Co-precipitation method produced finer CeO 2 particles than deposition-precipitation. • Strong correlation between CeO 2 crystallite size and lattice parameter profiles. • Metal-support interfacial area influenced the Cu state and product selectivity. CO 2 hydrogenation is one route for partial CO 2 abatement while producing valuable chemical products. Cu/CeO 2 catalysts have attracted great interest as materials that facilitate the efficient hydrogenation of CO 2 into methanol and CO. This paper investigates the effect of preparation methods on the structure, function and activity of Cu/CeO 2 catalysts. The catalysts have been prepared by deposition–precipitation (DP) and the co-precipitation (CP) methods. The activity tests for the catalysts were conducted in a high-pressure packed bed reactor in the temperature range of 200–300 °C at 50 bar pressure. The DP catalyst showed higher methanol productivity and lower methanol selectivity compared its CP counterpart. The reasons for the higher performance of the DP catalyst and other structural and functional differences have been investigated through in-depth characterization using synchrotron radiated in-situ powder diffraction, DRIFTS, XPS, HR-TEM, TPR and N 2 O decomposition used to determine copper surface area. The higher methanol productivity in the DP catalyst was attributed to the higher Cu surface area and dispersion. Additionally, the in-situ synchrotron-based powder diffraction measurements provide fundamental insights on the interesting differences in the CeO 2 structure i.e. the lattice parameter and the lattice microstrain during the reduction step that could be attributed to the size difference in the CeO 2 support nanoparticles. [ABSTRACT FROM AUTHOR]

• A bifunctional Ru–Pd catalyst was synthesized by a facile impregnation–hydrogen reduction method. • The catalyst has excellent catalytic activity for both hydrogenation and dehydrogenation of LOHCs. • No significant activity decrease was observed after several hydrogenation and dehydrogenation cycles. • The dehydrogenation activity of the Ru–Pd/Al 2 O 3 catalyst is superior to that of a commercial Pd–Al 2 O 3 catalyst. Hydrogen storage and release by liquid organic hydrogen carriers (LOHCs) are achieved by a reversible catalytic hydrogenation and dehydrogenation process. Generally, catalytic hydrogenation and catalytic dehydrogenation require different noble metal catalysts. In this paper, we report a bifunctional Ru–Pd/Al 2 O 3 catalyst with excellent catalytic activity for both hydrogenation and dehydrogenation of LOHCs. All catalysts were prepared by a facile impregnation–hydrogen reduction method, and the catalytic activities were compared by catalytic hydrogenation of N-propylcarbazole and dehydrogenation of perhydro-N-propylcarbazole. The as-prepared Ru-Pd/Al 2 O 3 catalyst exhibits excellent catalytic hydrogenation and dehydrogenation activity, selectivity, and stability. Particularly, the dehydrogenation activity of the Ru–Pd/Al 2 O 3 catalyst is superior to that of the commercial Pd/Al 2 O 3 catalyst, which proves that the positive synergistic effect between palladium and ruthenium nanoparticles enhanced the activity of the Ru–Pd/Al 2 O 3 catalyst. No significant activity decrease was observed for the as-prepared catalysts after three cycles of N-propylcarbazole hydrogenation and three cycles of dehydrogenation. The bifunctional Ru–Pd catalyst has potential commercial applications in large-scale application of LOHC technology. [ABSTRACT FROM AUTHOR]

Energy security and waste management are gaining global attention. The modern world is producing a large amount of liquid and solid waste as a result of the increasing population and industrialization. A circular economy encourages the conversion of waste to energy and other value-added products. Waste processing requires a sustainable route for a healthy society and clean environment. One of the emerging solutions for waste treatment is plasma technology. It converts waste into syngas, oil, and char/slag depending on the thermal/non-thermal processes. Most of all the types of carbonaceous wastes can be treated by plasma processes. The addition of a catalyst to the plasma process is a developing field as plasma processes are energy intensive. This paper covers the detailed concept of plasma and catalysis. It comprises various types of plasma (non-thermal and thermal) and catalysts (zeolites, oxides, and salts) which have been used for waste treatment. Catalyst addition improves gas yield and hydrogen selectivity at moderate temperatures. Depending on the properties of the catalyst and type of plasma, comprehensive points are listed for the selection of the right catalyst for a plasma process. This review offers an in-depth analysis of the research in the field of waste-to-energy using plasma-catalytic processes. [Display omitted] • Sustainable approach towards waste valorization is highly imperative worldwide. • Synergistic effect of various catalysts and plasma has been reported. • Catalyst plasma technology gives up to 68% gas yield at 500 °C temperature. • This technology appears to be considerable alternative for waste conversion. • Limited information is available in literature on catalytic thermal plasma system. [ABSTRACT FROM AUTHOR]

Platinum group metals (PGMs), especially platinum (Pt), palladium (Pd), and rhodium (Rh), are widely used in automotive three-way catalysts (TWCs). PGM resources are scarce and unevenly distributed, with global reserves of 69,000 t in 2020, of which more than 99% are concentrated in South Africa, Russia, Zambia, and the United States. However, the demand for PGMs worldwide is growing continually, especially in China. The recovery of PGMs from spent TWCs not only can alleviate the contradiction between supply and demand but also have good economic and environmental benefits. This paper briefly analyzes the market demand for Pt, Pd, and Rh in the global automotive industry in recent years, emphasizing the importance of waste TWC recycling. It also presents the current status of waste TWC management in some countries, especially China, and critically reviews the main recycling strategies for waste TWCs. On this basis, suggestions for strengthening the management of waste TWCs in China are put forward, and the future development trend of recycling technology is foreseen. The purpose of this paper is to provide some valuable references for the decision-makers of waste TWC management, and hopefully to provide inspiration for related scholars on the future research direction of waste TWC recycling technology. [Display omitted] • The management regulations of waste TWCs in some countries, especially in China, was introduced. • The research progress of the main methods of PGMs recovery was critically reviewed. • Some management suggestions of waste TWCs and the future development trend of recycling technology are put forward. [ABSTRACT FROM AUTHOR]

Biomass valorization via catalytic gasification is a potential technology for commercizalization to industrial scale. However, the generated tar during biomass valorization posing numerous problems to the overall reaction process. Thus, catalytic tar removal via reforming, cracking and allied processes was among the priority areas to researchers in the recent decades. This paper reports new updates on the areas of catalyst development for tar reduction. The catalyst survey include metallic and metal-promoted materials, nano-structured systems, mesoporous supports like zeolites and oxides, group IA and IIA compounds and natural catalysts based on dolomite, palygorskite, olivine, ilmenite, goethite and their modified derivatives. The influence of catalyst properties and parameters such as reaction conditions, catalyst preparation procedures and feedstock nature on the overall activity/selectivity/stability properties were simultaneously discussed. This paper not only cover to model compounds, but also explore to real biomass-derived tar for consistency. The area that require further investigation was identified in the last part of this review. [Display omitted] • Catalytic biomass gasification is a promising technology in recent times. • Tar production is a great challenge associated with the process upgrade. • Different pure/modified catalysts are employed as tar reduction systems. • Recent literature details on these catalysts and allied parameters reviewed. • Mechanisms of actions and ways forward highlighted for research benefits. [ABSTRACT FROM AUTHOR]

Fenton system is one of the most popular methods to eliminate antibiotics and dyes in aquatic environment. However, the existed Fenton system is limited by various factors such as potential second pollution and narrow pH range. In this study, we report that the bottlenecks for high strength antibiotics and dyes wastewater treatment at a wide pH range can be well tackled by the nanoscale "yarn ball"-like Mo/W-containing heteropoly blue (HPB) catalyst Mg 2 Ti 6 Mo 23 O 119 SiW 12 (1). This novel catalyst displayed extremely efficient elimination for several typical organic contaminants such as malachite green (MG), tetracycline (TC) and methyl orange (MO). Compared with other materials reported in previous papers, the catalytic performance of 1 in degradation of the organic contaminants of high concentrations increased several times. More than 90% of antibiotics and dyes are degraded within 60 min. Electron spin resonance (ESR) experiments and UV–vis spectra confirmed that the catalytic mechanisms of 1 could mainly ascribe to the 1 /H 2 O 2 process and the possible photocatalytic oxidation of adsorbed H 2 O by holes (h+) in the valence band (VB) of 1 surface generated · OH for extremely efficient degradation of organic contaminants. This work widens the optimal pH values up to neutral condition and it's significant for the expansion of the heterogeneous Fenton-like catalyst family and its application in the field of water treatment. Image 1 • A HPB Fenton-like catalyst for degradation of antibiotics and dyes. • More than 90% of antibiotics and dyes are degraded within 60 min. • Widening the optimal pH values up to neutral condition. • Expanding the Fenton-like catalyst family and its application in the field of water treatment. [ABSTRACT FROM AUTHOR]

In this paper, a series of Sb modified CeZr 2 O x mixed oxides (Sb y CZ) were synthesized by citrate method for the selective catalytic reduction of NO with ammonia (NH 3 -SCR). Experimental results exhibited that the Sb addition could bring a great improvement of SCR activity at 200–360 °C owing to the enhancement in surface area, redox ability and surface acidity. More importantly, the sulfur tolerance of the catalyst with proper Sb loading contents was dramatically improved. For instance, above 85% deNO x efficiency was retained over Sb 0.5 CZ catalyst after 24 h reaction in the presence of 100 ppm SO 2 and 5 vol.% H 2 O. As for pure CeZr 2 O x and the catalysts with low Sb loading contents, the serious accumulation of ammonium sulfates resulted in the deactivation after SO 2 exposure. However, with excessive Sb addition, more labile oxygen readily reacted with SO 2 and the redox cycle was then disrupted, leading to the decrease of SCR activity. With an appropriate Sb loading contents, the sulfate species preferentially formed around Sb cations could restrain the further consumption of oxygen species in Ce-O-Ce or Ce-O-Zr mode by SO 2 via a space confinement effect. Thus, a certain amount of labile oxygen was preserved to drive the SCR reaction, thereby enhancing the sulfur tolerance of the catalyst. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract This paper reports the use of two layered hydroxide salts (LHS) (zinc hydroxide nitrate – ZHN – Zn 5 (OH) 8 (NO 3) 2 ·2H 2 O, and zinc hydroxide chloride – ZHC – Zn 5 (OH) 8 Cl 2 ·H 2 O) as catalysts for brilliant green (BG) organic dye bleaching, using hydrogen peroxide as oxidant. The LHS were prepared by precipitation reaction between an aqueous solution of zinc salts and an aqueous ammonia solution. The solids were characterized by powder X-ray diffraction (XRD), electron paramagnetic resonance (EPR), ultraviolet-visible electronic spectroscopy (UV–Vis) and Fourier-transform infrared spectroscopy (FTIR). The catalytic activity of the solids was investigated at temperatures of 25, 35 and 45 °C, using different molar ratios of oxidant:dye:Zn2+ ions (present in the catalyst), in the absence and presence of ambient light. The kinetic aspect of the reaction was investigated considering that the reaction showed pseudo-first order behavior in relation to BG dye concentration. We propose a mechanism where superoxide radicals account for most of the bleaching taking place. The catalytic results obtained, along with the low cost and low toxicity of zinc compounds, establish ZHN and ZHC as novel catalysts for dye wastewater treatment, an area with constant demand for new methods and materials given its relationship with environmental equilibrium and human health. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CD-assisted Ni-Pd bimetallic catalysts were prepared by different impregnation routes. • The best method involves the pre-adsorption of CD on Al 2 O 3 before adding metal salts. • High dispersion of surface Ni nanoparticles (5–6 nm) along with surface Pd enrichment. • A 71% yield to n-octylamine was achieved in the reaction of 1-octanol with ammonia. Abstract This paper reports the use of β-cyclodextrin as a pre-shaping agent for the preparation of low-metal xNi-yPd/Al 2 O 3 catalysts (x = 2, 5 wt% and y = 0.2, 0.5, 1.0 wt%) targeting the direct amination of 1-octanol with ammonia. Six different preparation methods were used aiming at tuning the Ni-Pd interaction. The catalysts were finely characterized by XRD, H 2 -TPR, CO pulse chemisorption, STEM-EELS/EDS-SDD and XPS, while the elementary interaction between Ni-Pd-cyclodextrin was assessed by marrying ESI-MS experiments with DFT calculations. Among the different methods studied, the most outstanding effect was obtained when β-cyclodextrin was pre-adsorbed on γ-Al 2 O 3 before impregnating the Ni and Pd nitrate precursors. At such conditions, the best formulation (5Ni-0.5Pd/Al-CD_M4) afforded 90% conversion and 71% yield to 1-octylamine (TON = 93) in the amination of 1-octanol with ammonia at 160 °C for 4 h, which places it among the most active and selective Ni catalysts reported in the literature. [ABSTRACT FROM AUTHOR]

The development of green and efficient catalysts for peroxymonosulfate (PMS) activation and abatement of organic pollutants in wastewater is of significant practical interest. In this paper, the three-dimensional mixed manganese oxides of OMS-2 and γ-MnO 2 were fabricated through a simple refluxing method from KMnO 4 and MnSO 4 . It was found that growth of γ-MnO 2 nanoflakes on OMS-2 can be controlled by the concentration of MnSO 4 . The catalysts not only have many excellent structural properties such as interconnected network and highly exposed active sites, but also show the high ratio of low valent manganese species. In particular, the catalysts exhibited much higher efficiency for Acid Orange 7 degradation in the presence of PMS than pure OMS-2 or γ-MnO 2 . The oxidation of Mn(III) species by PMS occurs in the system with the formation of sulfate and hydroxyl radicals contributed to the dye degradation. Moreover, the catalysts showed good stability and reusability during four consecutive cycles. Thus, the environmental friendly mixed manganese oxides of γ-MnO 2 and OMS-2 with low cost, facile synthesis process and high efficiency are very promising catalysts for PMS activation and pollutants degradation. [ABSTRACT FROM AUTHOR]

Various catalysts are being used in fuel production from biomass and polymeric waste for the obtention of an alternative energy source with both environmental friendliness and economic viability. Biochar, red mud bentonite, and calcium oxide have been shown to play a pertinent role as catalysts in waste-to-fuel conversion processes, such as transesterification and pyrolysis. In this line of thought, this paper has provided a compendium of the fabrication and modification technologies of bentonite, red mud calcium oxide, and biochar, together with their various performances in their application in the waste-to-fuel processes. Additionally, an overview of the structural and chemical attributes of these components is discussed regarding their efficiency. Ultimately, research trends and future points of focus are evaluated, and it is observed that techno-economic optimization of catalyst synthetic routes and investigation of new catalytic formulations, such as biochar and red mud-based nanocatalysts, are potential prospects. This report also offers future research directions that are anticipated to contribute to the development of sustainable green fuel generation systems. [ABSTRACT FROM AUTHOR]

In this paper, multifunction nanoparticles (MNPs), Fe 3 O 4 @SiO 2 @Au MNPs, with properties of superparamagnetism, fluorescence and peroxidase-like catalytic activity were synthesized in the aqueous phase. The synthesized composites were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier translation infrared spectrum (FT-IR) and fluorometer. The results show that the multifunctional nanomaterials have good magnetic and fluorescence properties. Then, the mimetic properties of this material were investigated. The as-synthesized Fe 3 O 4 @SiO 2 @Au MNPs exhibited the best catalytic activity for peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) at the reaction temperature of 70 °C and pH of 3. Compared with free Fe 3 O 4 MNPs and BSA-Au nanoclusters (NCs), the composites have better catalytic activity at higher temperature and lower pH, indicating that Fe 3 O 4 @SiO 2 @Au MNPs can work in more severe environment. In practical application, we have successfully established the colorimetric method for the detection of H 2 O 2 and glucose with the detection range of 1 × 10 −6 ∼ 4 × 10 −5 M and 5 × 10 −6 ∼ 3.5 × 10 −4 M, and the detection limit of 6 × 10 −7 M and 3.5 × 10 −6 M, respectively. The method was also successfully applied in the detection of real samples. Furthermore, since the fluorescence of Fe 3 O 4 @SiO 2 @Au MNPs was quenched by H 2 O 2 , a method for the visual detection of glucose was established. [ABSTRACT FROM AUTHOR]

In this paper, the influence of 3 -glycidoxypropyltriethoxysilane (GPTES) based organic-inorganic coatings on the properties of treated textile fabrics was studied. All experimental results were deeply analyzed and thereafter correlated with the employed silica precursor concentration and with the presence of the BF 3 OEt 2 (Boron trifluoride diethyl etherate), used as epoxy ring opening catalyst. SEM analysis, FT-IR spectroscopy, X-ray Photoelectron Spectroscopy (XPS), thermogravimetric analysis (TGA) and washing fastness tests of the sol-gel treated cotton fabric samples were firstly exploited in order to characterize the morphological and structural features of the achieved coatings. Finally, the influence of the resulting nanohybrid coatings was explored in terms of abrasion resistance, tensile strength and elongation properties of treated cotton, polyester and silk fabrics. The catalyst amounts seem to strongly improve the formation of coatings, but still they do not influence the wear resistance of treated textile fabrics to the same extent. Indeed, it was found that increasing catalyst/GPTES ratio leads to a more cross linked inorganic 3D-network. GPTES itself was not found to affect the bulk properties of the selected textile and the resulting coatings were not so rigid to hardly modify the mechanical properties of the treated samples. Finally, it is worth mentioning that in all case the obtained 3 -glycidoxypropyltriethoxysilane-based chemical finishing have shown no cytotoxic effects on human skin cells. [ABSTRACT FROM AUTHOR]

Platinum catalysts derived from MOF have shown excellent potential in oxygen reduction reaction (ORR) of fuel cells. In this paper, we applied a simple and efficient synthesis method to prepare ZIF-67-R x (x ​= ​0–4) with different sizes. Co@MOF-R x (x ​= ​0–4) skeleton supports with carbon nanotube structure were obtained by further pyrolysis. Pt/Co@MOF-R x (x ​= ​0–4) catalysts were synthesized by loading Co@MOF-R x with 10% Pt. By changing the content of metal precursor, the nanometer size of ZIF-67-Rx was reduced from 722 ​nm to 93 ​nm. Pt/Co@MOF-R x showed super high oxygen reduction activity and superior cycle stability. At 0.9 ​V, the mass activity(MA) and specific activity(SA) were 9.63 ​mA mg Pt −1and 1.33 ​mA ​cm2, respectively, which were 1.54 and 1.23 times higher than those of Pt/C(20%). After 6000 cycles, it shows excellent stability than Pt/C(20%). This work brings new opportunities to design and prepare promising catalyst supports for proton exchange membrane fuel cells. [Display omitted] • ZIF-67 with different sizes was prepared, and its nano size decreased from 722 ​nm to 93nm. • Co and Pt are used as active sites in Pt/Co@MOF-R2, respectively. • Pt/Co@MOF-R 2 exhibited ultra-high oxygen reduction activity, and its mass activity (@0.9 ​V) and specific activity (@0.9 ​V) were 1.54 and 1.23 times that of Pt/C (20%). [ABSTRACT FROM AUTHOR]

In this study, the melamine (Mel) modification method was adopted to optimize the NH 3 -SCR activity of Ce 20 W 10 Ti 100 O z doped with C or/and N elements. It was found that with the improved doping of C or/and N into the lattice of anatase TiO 2 of Ce 20 W 10 Ti 100 O z , the dispersion of tungsten/cerium species and the conversion of partial Ce4+ to Ce3+ on its surface were signicantly enhanced, resulting in a large improvement of its surface chemical adsorbed oxygen(O α) concentration. Interestingly, the enhancement of Mel/Ti(SO 4) 2 mass ratio slightly decreases the surface N/O α concentrations, but further improves the surface Ti concentration and Ce3+/(Ce3++Ce4+) molar ratio. Furthermore, Mel modification increases the surface/sub-surface oxygen relative concentrations of Ce 20 W 10 Ti 100 O z , although decreases its low-temperature reducibility and acidity. Due to the larger N doped amount, Ce 20 W 10 Ti 100 O z -Mel t :Ti ​= ​1:2 shows higher surface acidity and O α /(O α +O β) molar ratio than Ce 20 W 10 Ti 100 O z -Mel t :Ti ​= ​4:2, which might be responsible for its improved catalytic performance due to the melamine (Mel) modification. In this paper, melamine (Mel), the nitrogen and carbon-rich material, was firstly used to modify Ce 20 W 10 Ti 100 O z catalyst via the hydrothermal co-precipitation method to promote the NH 3 -SCR activity. [Display omitted] • C/N elements were doped to improve the NH 3 -SCR activity of Ce 20 W 10 Ti 100 O z via Mel modification. • The effect of Mel modification on the physicochemical properties of the catalyst was revealed. • Regulating the relative doping of C or/and N to affect the activity of the catalyst. [ABSTRACT FROM AUTHOR]

Improving the bioleaching efficiency of metals from spent mobile phone printed circuit boards (PCBs) in a short time has been of major interest in recent years. In this paper, a novel cheap catalyst (oak wood biochar) was used to improve the copper and nickel bioleaching efficiency from spent mobile phone PCBs. The biochar was derived from oak wood through slow pyrolysis at a low temperature of 500 °C for 1h. The results of RSM optimization indicated that the optimum conditions to maximize copper and nickel recovery were 1.6 g/L biochar and 16 g/L pulp density. The findings indicated that compared to without the presence of biochar, the leach yields of copper and nickel were high. As much as 98% of copper and 82% of nickel were leached by indirect bioleaching under optimum conditions. The better performance in the presence of biochar is due to both galvanic interactions between biochar and solid waste. The biochemical characterization of bioleaching solution suggested that the high concentration of biochar (> 1.6 g/L) led to copper absorption by functional groups on the surface of biochar. Compared to chemical leaching, the bioleaching has better performance. Under optimum conditions, the copper and nickel recovery by indirect bioleaching was 36% and 64% more than that by chemical leaching. Also, it is found that biochar has a positive effect on the chemical leaching process. Therefore, in this paper, the function of biochar was elaborated not only in bio-hydrometallurgy but also in the hydrometallurgy process. Image 1 • Developing a new catalytic agent to improving metal recovery. • Under optimum condition, 98% of Cu and 82% of Ni were leached from spent PCBs. • The synthesized biochar significantly decreased leaching time to 72 h. • The recovery of metals was higher in microbial leaching compared to chemical leaching. [ABSTRACT FROM AUTHOR]