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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] • 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]

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]

[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]

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] 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]

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]

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]

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]

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]

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]

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]

In this paper, a series of catalysts about CeO 2 active sites prepared using reduced TiO 2 (TiR) as supports were firstly used for selective catalytic reduction (SCR) of NO by NH 3 . The catalytic performance evaluation results showed that the NO removal efficiency of CeO 2 /TiR (CeTiR) was much higher than that of CeO 2 /TiO 2 (CeTi). Hence, the aim of this study was to investigate the promotion mechanism of catalytic performance of CeTiR catalysts. The catalysts were characterized by XRD, BET, Raman, XPS, NH 3 -TPD and H 2 -TPR. The results of characterization revealed that CeO 2 had a strong interaction with oxygen vacancies of TiR supports. The strong interaction resulted in more Ce 3+ formation and better redox properties for CeTiR catalysts. In addition, it was confirmed that the better redox properties of CeTiR could be considered as the major reason of its high SCR activity via L-H mechanism but not acid properties. We expected that this study could shed some lights on the development of SCR catalysts for improving the interaction between Ti support and active species for enhancing SCR reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] The size of silver nanoparticles (Ag NPs) and loading amount of Ag NPs onto their substrate/carrier are two key factors for their efficient applications. Herein, we present a facile method for in situ synthesizing ultrafine and highly loaded Ag NPs on the surface of tannin-coated catechol-formaldehyde resin (TA-CFR) nanospheres. TA-CFR nanospheres act as green and highly efficient reducing agents for converting silver ions (Ag+) into Ag NPs, and the size of resultant Ag NPs is only ∼ 7.5 nm, and the Ag NPs loading capacity of TA-CFR is as high as 61.5 wt%, both of which contribute to the very high specific surface area of Ag NPs. Consequently, the as-synthesized TA-CFR@Ag composites show high catalytic performance, and the catalytic rate for the reduction of 4-nitrophenol is almost 10 times higher than that of the control. Meanwhile, TA-CFR@Ag composites also possess high antibacterial activity, efficiently inhibiting the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, tannin coating (thickness: ∼ 15 nm) minimizes the aggregation of Ag NPs, and enhances the reusability and stability of resultant Ag NPs, because of their high surface charges (the zeta potential is up to −65.5 ± 1.9 mV) and strong coordination capability with Ag NPs. This work provides a new frontier to develop multifunctional nanomaterials focusing on the green catalyst synthesis and environmental-remedy applications. [ABSTRACT FROM AUTHOR]