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Hydrogen fuel is a non-toxic and source-abundant energetic system, but for its applications in the industry, several issues related to its storage must be resolved. Compounds like NaBH 4 appear as promising hydrogen sources, while can release the latter rapidly under controllable conditions with the use of heterogeneous catalyst systems. In this work, we synthesized a Ni–CoP catalyst by electrodeposition in a three-step process on carbon paper as support. The materials were characterized via SEM-EDS, XRD, and XPS techniques, while the hydrogen evolution reaction (HER) from alkaline NaBH 4 solutions was tested as a batch experiment. Ni–CoP catalyst showed a high amount of H 2 generated in a short time (∼550 mL in 1 min) and remained at 78 and 54% of its initial performance after respectively 100 and 300 h of a continuous hydrolysis process. Our catalyst revealed exceptional performance and stability at higher temperatures and a long process time, which have been a rare subject of investigation in other reports for NaBH 4 hydrolysis in the past. This work paves a new perspective in studying catalysts for hydrogen generation from borohydrides. [Display omitted] • Ni–CoP catalyst was electrodeposited on a carbon support. • Material characterization proved the formation of desired active layers. • High efficiency and stability of the catalyst for a long-term NaBH 4 hydrolysis was revealed. [ABSTRACT FROM AUTHOR]

In recent years, the catalyst efficiency of hydrogen evolution reaction (HER) has been extensively studied. However, the stability of catalysts at high current densities is still a challenge. Herein, layered Ni−Co−P was electrodeposited on carbon fiber paper (CFP) via cyclic voltammetry (CV). This low‐cost electrode exhibits high efficiency and excellent durability for HER in 1 M KOH. To achieve current densities of 10, 100, 500, and 1000 mA cm−2, Ni−Co−P/CFP required overpotentials of 49, 95, 170, and 295 mV, respectively. The layered structure allows the catalyst to fall off layer by layer. After the outer layer of catalyst falls off, the inner layer of catalyst will be exposed to continue working. After 300 h of HER at 1000 mA cm−2, Ni−Co−P/CFP still has a regular morphology and high efficiency. Our work shows that layered Ni−Co−P/CFP has excellent prospects for practical applications. [ABSTRACT FROM AUTHOR]

• Co doped MoS 2 was decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) by a solvothermal process. • The lattice spacing of (1 0 0) plane of Co-MoS 2 was slightly narrow than that of MoS 2. • The as-prepared Co-MoS 2 /NCFCP hybrids showed enhanced electrochemical activity for HER. In this paper, Co-doped MoS 2 (Co-MoS 2) with various Co/Mo mole ratio (6%–12%) decorated on nitrogen-doped carbon fiber/carbon paper (NCFCP) (Co-MoS 2 /NCFCP) is fabricated by a solvothermal method as an efficient electrocatalyst for hydrogen evolution reaction (HER). The NCFCP substrate is prepared by electrochemical deposition of polypyrrole on carbon paper followed by heat treatment. The obtained 9% Co-MoS 2 /NCFCP hybrid catalyst exhibits an excellent electrocatalytic HER activity with a low overpotential of 174 mV at 10 mA cm−2, a small Tafel slope of 52 mV dec−1 and long-term stability. Thus, Co-MoS 2 /NCFCP hybrid holds high potential as an efficient earth-abundant electrocatalyst material for HER. [ABSTRACT FROM AUTHOR]

This multi-disciplinary paper aims to provide a roadmap for the development of an integrated, process-intensified technology for the production of H2, NH3 and NH3-based symbiotic/smart fertilizers (referred to as target products) from renewable feedstock with CO2 sequestration and utilization while addressing environmental issues relating to the emerging Food, Energy and Water shortages as a result of global warming. The paper also discloses several novel processes, reactors and catalysts. In addition to the process intensification character of the processes used and reactors designed in this study, they also deliver novel or superior products so as to lower both capital and processing costs. The critical elements of the proposed technology in the sustainable production of the target products are examined under three-sections: (1) Materials: They include natural or synthetic porous water absorbents for NH3 sequestration and symbiotic and smart fertilizers (S-fertilizers), synthesis of plasma interactive supported catalysts including supported piezoelectric catalysts, supported high-entropy catalysts, plasma generating-chemical looping and natural catalysts and catalysts based on quantum effects in plasma. Their performance in NH3 synthesis and CO2 conversion to CO as well as the direct conversion of syngas to NH3 and NH3—fertilizers are evaluated, and their mechanisms investigated. The plasma-generating chemical-looping catalysts (Catalysts, 2020, 10, 152; and 2016, 6, 80) were further modified to obtain a highly active piezoelectric catalyst with high levels of chemical and morphological heterogeneity. In particular, the mechanism of structure formation in the catalysts BaTi1−rMrO3−x−y{#}xNz and M3O4−x−y{#}xNz/Si = X was studied. Here, z = 2y/3, {#} represents an oxygen vacancy and M is a transition metal catalyst. (2) Intensified processes: They include, multi-oxidant (air, oxygen, CO2 and water) fueled catalytic biomass/waste gasification for the generation of hydrogen-enriched syngas (H2, CO, CO2, CH4, N2); plasma enhanced syngas cleaning with ca. 99% tar removal; direct syngas-to-NH3 based fertilizer conversion using catalytic plasma with CO2 sequestration and microwave energized packed bed flow reactors with in situ reactive separation; CO2 conversion to CO with BaTiO3−x{#}x or biochar to achieve in situ O2 sequestration leading to higher CO2 conversion, biochar upgrading for agricultural applications; NH3 sequestration with CO2 and urea synthesis. (3) Reactors: Several patented process-intensified novel reactors were described and utilized. They are all based on the Multi-Reaction Zone Reactor (M-RZR) concept and include, a multi-oxidant gasifier, syngas cleaning reactor, NH3 and fertilizer production reactors with in situ NH3 sequestration with mineral acids or CO2. The approach adopted for the design of the critical reactors is to use the critical materials (including natural catalysts and soil additives) in order to enhance intensified H2 and NH3 production. Ultimately, they become an essential part of the S-fertilizer system, providing efficient fertilizer use and enhanced crop yield, especially under water and nutrient stress. These critical processes and reactors are based on a process intensification philosophy where critical materials are utilized in the acceleration of the reactions including NH3 production and carbon dioxide reduction. When compared with the current NH3 production technology (Haber–Bosch process), the proposed technology achieves higher ammonia conversion at much lower temperatures and atmospheric pressure while eliminating the costly NH3 separation process through in situ reactive separation, which results in the production of S-fertilizers or H2 or urea precursor (ammonium carbamate). As such, the cost of NH3-based S-fertilizers can become competitive with small-scale distributed production platforms compared with the Haber–Bosch fertilizers. [ABSTRACT FROM AUTHOR]

The continuous ortho-para hydrogen conversion technology represented by the plate-fin heat exchanger filled with catalyst (PFHEFC) is one of the key technologies for the breakthrough of large-scale hydrogen liquefaction system. An appropriate numerical model of the PFHEFC can provide reference and guidance for its design. The thermal-hydraulic behaviors of the catalyst filled layer (CFL) are essential for the model development of the PFHEFC. In this paper, the thermal-hydraulic correlations of the high-pressure and low-temperature hydrogen in the CFL are investigated by the numerical simulation and then used to improve the existing numerical models of the PFHEFC. The results show that the simulation results of the face centered cubic (FCC) packing structure are close to the results of some classical correlations of the CFL with most relative deviations within ±10% and can be used to approximate the actual CFL. And taking 40 K as the dividing point, the new thermal-hydraulic correlations of the high-pressure and low-temperature hydrogen in the CFL are obtained with the relative deviations within ±10%. Further, the New model of the PFHEFC is developed with the new thermal-hydraulic correlations. The New model has some margin in the heat transfer performance, considers the special thermal-hydraulic performances of the high-pressure and low-temperature hydrogen in the CFL, and is consistent with the existing numerical models in the ortho-para hydrogen conversion performance. It shows the New model is more suitable for the PFHEFC and can provide more accurate results for the design of the PFHEFC than the existing numerical models. • Assumption of the FCC approximating the actual CFL is reasonable and enforceable. • Thermal-hydraulic behaviors of high-pressure hydrogen at 30–80 K in the CFL are analyzed. • Porosity is a nonnegligible parameter affecting the thermal-hydraulic performances of the CFL. • New thermal-hydraulic correlations of high-pressure hydrogen at 30–80 K are obtained. • New model of the PFHEFC is proposed and is better than the existing numerical models. [ABSTRACT FROM AUTHOR]

In this paper, the relationship between the structural features of hematite samples calcined in the interval of 800–1100 °C and their reactivity regarding hydrogen studied in the temperature-programmed reaction (TPR-H2) was studied. The oxygen reactivity of the samples decreases with the increasing calcination temperature. The study of calcined hematite samples used X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Raman spectroscopy, and their textural characteristics were studied also. According to XRD results, hematite samples calcined in the temperature range under study are monophase, represented by the α-Fe2O3 phase, in which crystal density increases with increasing calcination temperature. The Raman spectroscopy results also register only the α-Fe2O3 phase; the samples consist of large, well-crystallized particles with smaller particles on their surface, having a significantly lower degree of crystallinity, and their proportion decreases with increasing calcination temperature. XPS results show the α-Fe2O3 surface enriched with Fe2+ ions, whose proportion increases with increasing calcination temperature, which leads to an increase in the lattice oxygen binding energy and a decrease in the α-Fe2O3 reactivity regarding hydrogen. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is a new type of renewable energy that can meet people's growing energy needs and is environmentally friendly. In order to improve the industrial application prospects and electrochemical performance of hydrogen evolution catalysts, extensive research on transition metal materials has been carried out. Among the many catalytic materials, cobalt is an element with potential for the hydrogen evolution reaction (HER) due to its abundant reserves, low cost, and small energy barrier for H adsorption. This review classifies the latest research on cobalt-based catalysts according to the types of compound, including cobalt-based sulfides, phosphides, carbides, borides, oxides, etc., and summarizes the latest research progress of cobalt-based compound catalysts in acidic and alkaline media. Strategies to tune the properties of cobalt-based compound catalysts for high catalytic activity for HER are focused on, including structural engineering, defect engineering, and doping, etc. The advantages and limitations of each modified approach are reviewed. Not only that, but also the catalytic activity and advantages of the catalyst are evaluated by using density functional theory (DFT) calculation-related descriptors, activity evaluation parameters, etc. Finally, limitations and challenges of cobalt-based materials for HER are presented, as well as prospects for future research. This paper aims to understand the chemical and physical factors that affect cobalt-based catalysts, and to find directions for future research on cobalt-based catalysts. [ABSTRACT FROM AUTHOR]

Summary: Catalysts with cobalt (Co) and graphitic carbon hybrid structure are receiving significant attention in various electrocatalysis applications because of their stability and high activities. In addition, the size and the well dispersed distribution of metal active site are some of the most important factors for electrocatalyst. In this paper, we successfully synthesized ultra‐small and well dispersed Co nanoparticle on nitrogen‐doped carbon structure (Co/NC) adding and evaporating a Zinc (Zn) and found the optimized ratio of Co and Zn. We used a bottom‐up method to synthesize catalysts with Co on carbon substrate structure from zeolitic imidazolate frameworks (ZIF). Zinc (Zn) was also added and evaporated by pyrolysis. By addition and evaporation of Zn, Co nanoparticle became smaller and more evenly dispersed. As a result, the OER performance was significantly improved than the catalyst without Zn. Also, an optimized catalyst with abundant uniformly dispersed Co was successfully synthesized by appropriately controlling the ratio of Co and Zn comprising the ZIFs. As the ratio of Zn increased, the size and the amount of Co nanoparticles were decreased, and Co nanoparticles were more evenly dispersed. Furthermore, carbon substrate has more porous structure due to the evaporation of Zn atoms. When the Co:Zn ratio was 1:3, Co/NC showed the best electrocatalytic performance due to optimized active sites and large surface area. The optimized Co/NC showed an overpotential of 1.56 V (vs RHE) to acquire a current density of 10 mA cm−2, which is higher activity than commercial RuO2. We also analyzed the material characterization occurred as the ratio of Zn in ZIF increased, revealing the factors enhancing the OER activity. Optimized Co/NC (Co:Zn = 1:3) exhibited improved OER activity and long‐term and cycle stability in the OER. [ABSTRACT FROM AUTHOR]

Steam reforming (SR) of bio-oil has been considered as one of the promising methods for hydrogen production. In this paper, cerium modified Ni/Attapulgite (ATP) catalysts were successfully synthesized by traditional chemical precipitation method and utilized for SR of various bio-oil derived oxygenated model compounds. The effect of Ce content on the structural properties of Ni/ATP was investigated by ICP-OES, N2 adsorption–desorption, XRD, H2-TPR and HRTEM characterizations. The results exhibited that 10Ce–Ni/ATP catalyst had the strongest metal-support interaction and highly dispersion of Ni species with smallest particle size of 6.21 nm. Therefore, it presented the maximum ethanol conversion of 97.21% and H2 yield of 83.15% at relative lower reaction temperature 500 °C during 4 h of SR of ethanol (SRE). In addition, it unfolded promising performance for SR of acetic acid (SRAA) and acetone (SRA). Furthermore, the influence of different oxygenates on the amount and nature of carbon deposits in used 10Ce–Ni/ATP catalyst was revealed by TG and Raman analyses. It found that the types of feedstock significantly affected the carbon species and amount and the formation of graphic layers around the Ni metal sites was the mainly factor for rapid deactivation of 10Ce–Ni/ATP during 4 h of SRA reaction. [ABSTRACT FROM AUTHOR]

This article reports that researchers have scrambled to devise schemes for plucking select hydrogens off carbon and replacing them with other atoms that offer an easier handhold. A pioneer of this subfield, known as carbon-hydrogen (C-H) activation, Columbia University chemist Dalibor Sames has developed a wealth of advances along with his group members. Last week, the "Journal of the American Chemical Society," a leading chemistry journal, printed corrections for three papers from the Sames lab. Two of the papers on C-H activation catalysts were fully retracted, and part of a third was withdrawn. In each case, the retractions say that the work was disavowed after Sames group members could not reproduce the results following the departure of Bengü Sezen, a former Sames group graduate student, who was the lead author of the two retracted papers and a co-author of the third. Susan Brown, Columbia's director of public affairs, says that the university has launched a review of the case, but that she cannot comment on its scope or timing. In an e-mail exchange, Sezen, who is now a Ph.D. candidate in the group of University of Heidelberg molecular biologist Elmar Schiebel, according to the group's Web site, says that the retractions came as a surprise.

This paper is focused on the photocatalytic hydrogen production on Pd/TiO 2 (-WO 3) catalysts from water-methanol and water-glycerol mixtures under UVA and solar irradiation. The photodeposition method for Pd was studied varying conditions such as Pd amount, catalyst concentration and methanol concentration. The catalysts were tested at lab scale under simulated solar light and UVA radiation and also at large scale (25 L) under solar energy using a pilot-scale solar Compound Parabolic Collector (CPC). The catalysts characterization was performed by means of ICP-OES, N 2 adsorption–desorption isotherms, XRD, HR-TEM, XPS and DR–UV–Vis spectroscopy. Hydrogen evolution was monitored by on-line gas chromatography.From results it was found the Pd photodeposition method plays a key role to increase the hydrogen evolution, affecting parameters like the Pd amount deposited, the Pd nanoparticles size and dispersion. The highest quantum efficiency (ϕ) obtained in this study was 11.8% and 41.2% under simulated solar and UVA irradiation, respectively, using Pd(0.24 wt%)/P25 in an aqueous solution of methanol (50 vol%). In the pilot-scale solar CPC, for Pd(0.24 wt%)//P25 catalysts in 5 vol% of methanol or glycerol as sacrificial agents, the quantum yield were 2.1 and 2.2%, respectively. When the concentration of the sacrificial agents decreased to 0.37 vol%, the quantum yields were 1.3 and 2.4% for methanol and glycerol, respectively. Compared to literature, the low noble metal content of these catalysts (0.25 wt%) seems to be a competitive factor considering their high price. • Efficient catalysts for H 2 generation under solar radiation obtained by Pd photodeposition over TiO 2 and WO 3 supports. • Pd photodeposition method plays a key role in the hydrogen evolution, affecting parameters such as the nanoparticles size. • Low H 2 evolution with municipal wastewater demonstrates the challenges to overcome the photocatalytic H 2 generation. [ABSTRACT FROM AUTHOR]

Over the course of a few decades, the concern of environmental damages of fossil fuels, an increase in CO 2 emission and a decrease of hydrogen have been growing more and more. Accordingly, hydrogen production is a crucial issue nowadays. Different polymers are applied to attain the purpose. Among all polymers, biodegradables polymers are the best choices to develop the main aim. Polysaccharides and proteins are biodegradable polymers with unique places and advantages with regards to their ecofriendly properties. There are different techniques to apply and achieve the foremost purpose. It is worthwhile to mention that green and facile methods are always attracting attention in different aspects and fields. The three non-polluting and economical techniques, that is, electrochemical hydrogen evolution reaction (HER), photocatalytic technique, and hydrolysis of hydrides, are reviewed in this paper. This review helps researchers, who are environment supporters, to evaluate and choose the most ecological biopolymers and processes in their work. [Display omitted] • Developments in hydrogen evolution by biopolymer-derived (nano)catalysts have been described. • Summary of synthetic procedures to obtain biopolymer-derived (nano)catalysts. • Future challenges of hydrogen evolution using biopolymer-derived (nano)catalysts have been discussed. [ABSTRACT FROM AUTHOR]

This paper investigates the hot gas temperature effect on enhancing hydrogen generation and minimizing tar yield using zeolite and prepared Ni-based catalysts in rice straw gasification. Results obtained from this work have shown that increasing hot gas temperature and applying catalysts can enhance energy yield efficiency. When zeolite catalyst and hot gas temperature were adjusted from 250 °C to 400 °C, H 2 and CO increased slightly from 7.31% to 14.57%–8.03% and 17.34%, respectively. The tar removal efficiency varies in the 70%–90% range. When the zeolite was replaced with prepared Ni-based catalysts and hot gas cleaning (HGC) operated at 250 °C, H 2 contents were significantly increased from 6.63% to 12.24% resulting in decreasing the hydrocarbon (tar), and methane content. This implied that NiO could promote the water-gas shift reaction and CH 4 reforming reaction. Under other conditions in which the hot gas temperature was 400 °C, deactivated effects on prepared Ni-based catalyst were observed for inhibiting syngas and tar reduction in the HGC system. The prepared Ni-based catalyst worked at 250 °C demonstrate higher stability, catalyst activity, and less coke decomposition in dry reforming. In summary, the optimum catalytic performance in syngas production and tar elimination was achieved when the catalytic temperature was 250 °C in the presence of prepared Ni-based catalysts, producing 5.92 MJ/kg of lower heating value (LHV) and 73.9% tar removal efficiency. Image 1 • Prepared Ni-based catalyst can enhance hydrogen production in biomass gasification. • Zeolite at 400 °C generates more H 2 content comparing to prepared Ni-based catalyst. • Ni-based catalyst at 400 °C is deactivated by sulfur poison and coke decomposition. • Ni-based catalyst is not guaranteed to be effective for trace pollutants removal. [ABSTRACT FROM AUTHOR]

Ketones are of great importance in synthesis, biology, and pharmaceuticals. This paper reports an iridium complexes‐catalyzed cross‐coupling of alcohols via hydrogen borrowing, affording a series of α‐alkylated ketones in high yield (86 %–95 %) and chemoselectivities (>99 : 1). This methodology has the advantages of low catalyst loading (0.1 mol%) and environmentally benign water as the solvent. Studies have shown the amount of base has a great impact on chemoselectivities. Meanwhile, deuteration experiments show water plays an important role in accelerating the reduction of the unsaturated ketones intermediates. Remarkably, a gram‐scale experiment demonstrates this methodology of iridium‐catalyzed cross‐coupling of alcohols has potential application in the practical synthesis of α‐alkylated ketones. [ABSTRACT FROM AUTHOR]

In this paper, the dehydrogenation reaction of NaBH4 was performed in the presence of Co-ion loaded hydrogel catalyst. The reactions took place within 27, 18 and 9 hours at 25, 35 and 45 °C, respectively. In addition, the relation between the initial concentration of NaBH4 and released hydrogen was investigated at 45°C. A linear relationship between initial borohydride concentration and produced H2 was determined. Also, differential method was used to determine reaction rate constants and rate order. Hence, first-order-kinetics was proved by using experimental data. After that, the activation energy was found as 58.26 kJ/mol by means of the slope of the graph of lnk versus 1/T for the dehydrogenation reaction. This value is nearly equal to 50kJ/mol, which was expected in literature for the studies of the catalytic dehydrogenation. As the hydrophilic and macroporous structure of the prepared poly(acrylamide-co-acrylic acid) (p(AAm-co-AAc)-Co) hydrogel catalyst allowed inlet of NaBH4 solution up to its interior and release of produced H2, effect of pore diffusion limitation was neglected. Dehydrogenation index of NaBH4 was calculated as 2526.31 mL H2/g NaBH4 according to the amount of NaBH4 in the aqueous solution. [ABSTRACT FROM AUTHOR]

Recently, hydrogen is utilized by numerous chemical industries as an alternate over non-renewable fuels, and surely it will be considered as an important fuel in the near future. This paper reports a review of various reforming technologies for hydrogen production from butanol produced by fermentation of feedstocks like wheat, sugar beets, sugar cane, etc. with a number of aspects involving selection of an appropriate catalyst to suppress undesirable products as many reforming reactions are dependent on the catalyst properties to enhance the formation of significant fuels which may fulfill the future energy needs. An overview of butanol reforming processes with experimental and theoretical studies in order to grasp possibilities and restrictions of these processes is not comprehensively presented yet. In this paper, an assessment of published articles in brief related to essential parameters to carry out a pertinent research in the future is presented for the advancement of fuel processing technologies. [ABSTRACT FROM AUTHOR]

Chemical hydrogen storage in molecules such as ammonia (>17 wt% H 2) have the unique potential to overcome the current storage and transport limitations of the H 2 economy. However, sustainable on-demand production of hydrogen via ammonia decomposition, requires the development of novel transition metal-based catalysts beyond the current use of highly active but expensive ruthenium to ensure economic feasibility. In this paper, we provide fundamental understanding of the effects of a range of synthetic methods of Co/γ-Al 2 O 3 catalysts on the resulting ammonia decomposition activity. The main activity determining factors are collectively the reducibility of the cobalt species and their particle size. This systematic work demonstrates that decreasing the cobalt particle size enhances the ammonia decomposition catalytic activity. However, a careful balance is required between a strong metal-support interaction leading to small particle sizes (promoted by precipitation methods) and the formation of inactive cobalt aluminate species (encouraged by adsorption methods). In addition, impurities such as boron and chloride remaining from particular synthetic methods were found to have detrimental effects on the activity. Image 1 • High H 2 production from ammonia on cobalt-based catalysts. • Guidance for future cobalt-based catalysts development to replace scarce Ru. • Cobalt particle size plays a key parameter on ammonia decomposition activity. • Cobalt catalyst preparation method affects its size and interaction with support. • Strong-cobalt support interaction leads to formation of unreducible and inactive species. [ABSTRACT FROM AUTHOR]

Synthesis of catalysts with high activity for hydrogen evolution reaction (HER) has been a hot topic in electrocatalysis. In this paper, using MIL-88A(Fe) metal-organic complex, polyoxometalate (POM) and H2PtCl6 as starting materials, hierarchic and low Pt0-loading micro-rods (denoted as Pt-POMFe, i.e. Pt-PW12Fe or Pt-PMo12Fe) have been synthesized, in which the Pt0 nanoparticles can be stabilized by POM. The Pt-PW12Fe micro-rod containing [PW12O40]3- polyoxoanion component (0.30% Pt0-loading) which retains the spindle structure of its parent MIL-88A(Fe) exhibits a low overpotential of 28 mV at current density of 10 mA·cm−2 for HER that is close to the electrocatalytic effect of commercial Pt/C (ca. 20% Pt0-loading). Such high electrocatalytic reactivity is mainly caused by the synergistic effect of the three components of POM, Pt0, and Fe3O4@C. The structure effectively increases the active sites of the catalyst and improves its conductivity and stability. The Pt-POMFe catalyst extends a new family of MOF-POM functional materials and provides a new concept to the design and synthesis of highly-efficient and low-cost electrocatalyst for hydrogen production. [ABSTRACT FROM AUTHOR]

In this paper, we present a solvothermal synthesis of iron phosphide electrocatalysts using a triphenylphosphine (TPP) precursor. The synthetic protocol generates Fe 2 P phase at 300 °C and FeP phase at 350 °C. To enhance the catalytic activities of obtained iron phosphide particles heat-treatments were carried out at elevated temperatures. Annealing at 500 °C under reductive atmosphere induced structural changes in the samples: (i) Fe 2 P provided a pure Fe 3 P phase (Fe 3 P−500 °C) and (ii) FeP transformed into a mixture of iron phosphide phases (Fe 2 P/FeP−500 °C). Pure Fe 2 P films was prepared under argon atmosphere at 450 °C (Fe 2 P−450 °C). The electrocatalytic activities of heat-treated Fe 2 P−450 °C, Fe 3 P−500 °C, and Fe 2 P/FeP−500 °C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M H 2 SO 4. The HER activities of the iron phosphide catalyst were found to be phase dependent. The lowest electrode potential of 110 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2 was achieved with Fe 2 P/FeP−500 °C catalyst. Image 1 • Iron phosphides catalyst were synthesized via a wet-chemistry method. • Spin-coating of iron phosphide particles onto graphite substrates yielded uniform thin films. • Heat treatment of iron phosphides at 500 °C resulted in structural changes. • The iron phosphide films were used as electrocatalysts for efficient hydrogen evolution. [ABSTRACT FROM AUTHOR]

Steam reforming of biomass pyrolysis oil or bio-oil derivatives is one of the attractive approaches for hydrogen production. The current research focused on the development of promising catalysts with favorable catalytic activity and high coke resistance. Noble metal such as Rh has been proven to achieve promising reforming reaction efficiencies. However, Ni has attracted considerable attention owing to its stability, cost effectiveness, and good activity in breaking C–C and C–H bonds. Nevertheless, Ni-based catalysts have serious carbon deposition problems arising from chemical poisoning, metal sintering, and poor metal dispersion. This paper attempted to review the current trends in catalyst development considering the aspects of supports, metals, and promoters as an effort to find possible solutions for the limitations of Ni-based catalysts. The present review also covered the current understanding on the reaction mechanisms as well as the future prospects in the field of steam reforming catalysts. Image 1 • Catalysts efficiency rely on nature of metal, support, and metal-support interface. • Advanced catalyst synthesis is a new direction for achieving promising catalyst. • Mechanism of oxygenates compounds steam reforming is well discussed. • Further studies to elucidate mechanism of bio-oil steam reforming are required. [ABSTRACT FROM AUTHOR]

This paper presents high-performance Ni-YSZ tubular catalysts for CO 2 methanation prepared by the extrusion molding. We fabricated tubular-shaped Ni-YSZ catalysts with various Ni contents (25–100 wt% NiO) and investigated the effect of Ni content on CO 2 methanation performance under various temperatures and gas flow rates. Catalysts with Ni contents >75 wt% showed CH 4 yields >91% above 270 °C with high CH 4 selectivities (>99%). High CH 4 yields were also observed under high GHSVs at 300 °C: 93% and 92% at 8700 and 17,500 h−1, respectively. Investigation of methanation with the catalysts revealed that CO 2 methanation was accelerated by a localized hotspot at the reactor inlet arising from the interaction between reaction kinetics and heat generation. Using a numerical simulation, we considered the optimum arrangement of catalytic activity in the reactor to avoid hotspot generation and realize a stable high CO 2 methanation performance. We can simultaneously achieve high CH 4 production and prevent hotspot formation by properly arranging catalysts with different activities. • Ni content >75% gave CH 4 yields >91% above 270 °C with selectivities >99%. • Inlet hotspot arises from interaction of heat generation and reaction acceleration. • Increasing catalytic activity along reactor length can avoid hotspot formation. [ABSTRACT FROM AUTHOR]

In this paper energy dispersive spectroscopy, X-ray diffraction and Williamson-Hall grain size/strain characterization techniques were used to determine the effect exhaust water electrical conductivity, heating and electrical current had on Proton Exchange Membrane electrocatalyst degradation and the underlying mechanism. Quartz containing polybenzimidazole polymer had 6 nm of platinum sputter-coated and while 50 to 400 cycles of either 0.7 mA or 30 mA current were applied. Results showed between 38% (overall) and 100% (locally) platinum removal using 0.7 mA (400 cycles) or 30 mA (50 cycles) using water with 5 vol% acetic acid. The acetic acid increased the water's electrical conductivity and helped transport quartz to the sample surface to interact with the platinum. This interaction increased quartz's lattice strain to 1.4% and resulted in detached platinum. Furthermore, similar results may occur using membranes formulated with acid side chains, which can leach during thermal decomposition and destroy stack performance. Image 1 • Heating >100 °C using water & acetic acid did not detach catalyst from membrane. • Electrical current, quartz & conductive water detached catalyst from membrane. • Electrically conductive water critical component to remove catalyst from membrane. • Larger electrical current magnitudes removed catalyst at faster detachment rates. • Mechanism involved diffusion of quartz & catalyst increasing quartz lattice strain. [ABSTRACT FROM AUTHOR]

In this paper, the new composite material Co–Mo–S/Ni(OH)2 has high hydrogen evolution ability under photoreaction, the hydrogen evolution of Co–Mo–S/Ni(OH)2 composite material reaches 357 μmol after reaction 3 h, and the catalyst still exhibits high photocatalytic activity after four cycles under light response. It shows that this new catalyst has high activity and stability. The results of XPS, TEM, SEM and XRD indicate that the composite catalyst is successfully synthesized. The results of PL and electrochemical experiments show that Ni(OH)2 attached to Co–Mo–S can increase the transfer of photogenerated electrons and reduce the recombination of electrons and holes. From the UV–visible and BET characterization, the presence of Ni(OH)2 increases the range of response of the Co–Mo–S to sunlight, the pore volume and surface range, which improves the absorption capacity of the catalyst for ErB. Therefore, Co–Mo–S/Ni(OH)2 has excellent application prospect. [ABSTRACT FROM AUTHOR]

In this paper, different methods to prepare a Pt/stainless steel mesh catalyst for catalytic hydrogen combustion are reported. Pt was deposited as a thin layer onto stainless steel mesh as a support matrix. Thermal treatment resulted in the formation of uniformly distributed near nano-sized Pt particles on the support's surface. The catalysts were evaluated for catalytic hydrogen combustion, and temperatures of between 420 and 520 °C were achieved and maintained at hydrogen flow rates of 0.2–0.4 Nl/min. SEM and EDX results indicate that stainless steel support calcination promoted the formation of a native oxide layer. This oxide layer stabilized Pt particles during hydrogen combustion procedures, effectively preventing significant Pt aggregation from occurring. It was also found that the Ni content of stainless steel promoted the catalytic hydrogen combustion reaction. • Pt/stainless steel mesh catalysts were developed and evaluated for catalytic H 2 combustion applications. • High temperatures associated with catalytic H 2 combustion allowed for significant Pt-aggregation. • Catalysts with stabilized Pt achieved H 2 combustion temperatures of 420–520 °C, which were maintained for several hours. • Spontaneous auto ignition occurred on catalysts above 40 °C. • Significant reduction in NO x formation occurs from catalytic combustion compared with naked flame combustion. [ABSTRACT FROM AUTHOR]

Food waste is a kind of wet bio-waste which has been a challenge for the ecological environment and disposal. In this paper, hydrogen production from subcritical water gasification (SbWG) of food waste with and without catalyst loading was systematically investigated. The effects of reaction temperature (300–360 °C), residence time (30–90 min), food waste concentration (10–30 wt%) and catalysts (Ni/γ-Al 2 O 3 , Ni/ZrO 2 , NaOH, KOH, and FeCl 3) were studied within a pressure range of 10.5–20 MPa. The optimal process condition for SbWG of food waste without catalysts loading was determined to be 360 °C and 90 min with 10 wt% food waste. The liquid products and hydrochar were characterized by TOC, TGA/DTG, and SEM. The TOC concentration of liquid products decreased vastly with increasing reaction temperature. The highest H 2 yield (1.88 mol/kg), H 2 mole fraction (35.01%), and H 2 selectivity (53.86%) were achieved at 360 °C for 90 min with 5 wt% loading of KOH. It can be concluded that the performance of the catalysts for improving hydrogen production in SbWG of food waste was in the following order: KOH > NaOH > Ni/γ-Al 2 O 3 > Ni/ZrO 2 > FeCl 3. The catalytic SbWG can be a potential alternative for energy conversion of food waste and hydrogen production. Image 1 • Catalytic subcritical water gasification of food waste was investigated. • Optimal operating condition were found to be 360 °C, 90 min with 10 wt% food waste. • Alkaline metals, Ni-based, and Lewis acid catalysts were comprehensively studied. • Activity of the catalysts was ranked as: KOH > NaOH > Ni/γ-Al 2 O 3 > Ni/ZrO 2 > FeCl 3. [ABSTRACT FROM AUTHOR]

• The predictive ability of ΔG H for TMPs is enhanced by the integrated algorithm. • In terms of data sources, simply combining experimental or calculated data. • Feature importance analysis includes global and local feature importance. Transition metal phosphides (TMPs) are potential substitutes for platinum group metal catalysts in hydrogen evolution reactions (HER) for sustainable energy. In this work, a novel machine learning (ML)-based technique for HER performance prediction of TMPs is presented. ΔG H , which assesses catalytic activity, was utilized as the expected target value and data from sources like collected papers and self-calculated data were also employed. The random forest (RFR) technique produced an R2 of 0.89 on the test set, while non-tree ML algorithms were utilized for learning and feedback. Additionally, TMPs of ΔG H were predicted using an original Ensemble learning technique. The ensemble learning method significantly increased the model's predictive effect and strengthened the model's stability and resilience, resulting in an R2 >0.85 on the test set for the tree algorithm model. The SHAP (SHapley Additive exPlanations) algorithm and RFR showed that the geometric means of atomic volume, first ionization energy, and p-orbital electron number significantly impact free energy performance evaluation by tree ML algorithms. These findings can effectively guide the design and development of new products. In conclusion, this approach offers a useful tool to assess TMPs' performance in HER studies. [Display omitted] [ABSTRACT FROM AUTHOR]

The bifunctional catalyst provided a novel platform for biomass pyrolysis to efficiently and cleanly produce hydrogen, realizing the high-value conversion of biomass. First, the effect of catalyst/biomass ratios on the reaction activity of the Mo 0.5 Ni 1 Ca 7 catalyst was investigated. On this basis, the effects of La 2 O 3 and LaCoO 3 stabilizers on the cycling stability of the Mo 0.5 Ni 1 Ca 7 catalyst were examined. Eventually, the catalytic mechanism and the anti-deactivation model of the Mo 0.5 Ni 1 Ca 7 -LaCoO 3 catalyst were proposed in this paper. The results showed that the LaCoO 3 perovskite-type stabilizer greatly enhanced the cycling stability of the catalyst. In particular, the H 2 yield of the Mo 0.5 Ni 1 Ca 7 -LaCoO 3 catalyst was slightly reduced from 402 mL g biomass − 1 to 392.05 mL g biomass − 1 after ten cycles, with a relative decrease of only 2.47%. After ten regeneration cycles, the Mo 0.5 Ni 1 Ca 7 -LaCoO 3 catalyst maintained high oxygen activity, demonstrating that the catalyst exhibited stable coke resistance. The surface structure of the catalyst was optimized after ten cycles with the formation of more fine particles, which allowed the catalyst to maintain a high activity. The excellent dispersion of the LaCoO 3 stabilizer effectively inhibited the sintering of CaO and NiO. It delayed the aggregation of CaMoO 4 , leading to a stable catalytic ability and adsorption capacity of the catalyst. [Display omitted] • Corn cob pyrolysis for hydrogen-rich gas realizes high value utilization of biomass. • The Mo 0.5 Ni 1 Ca 7 -LaCoO 3 catalyst has the largest NiO/Ni(OH) 2 and lattice oxygen ratio. • The CaMoO 4 alloy enhances the catalytic activity and stability of the catalyst. • The LaCoO 3 perovskite-type stabilizer inhibits active phase particle sintering. • After ten cycles, the H 2 yield is 392.05 ml/g, with a decrease of only 2.47%. [ABSTRACT FROM AUTHOR]

• Al-rich Cu@MFI catalyst was developed for furfuryl alcohol upgrading to pentanediols. • The maximum yield of pentanediols was 91.7%% in a continuous-flow reactor. • The excellent activity was attributed to the proximity of Brønsted acid and metal sites in Cu@HZ40. • The catalyst exhibits excellent anti-sintering performance in a high-temperature hydrogen environment. Bifunctional metal-acid catalysts have been widely used in the process of upgrading the molecules of biomass. As an important bifunctional catalyst, metal @ zeolite exhibits excellent sintering resistance and efficient catalytic performance, which is significant for improving practical applications. While the development of Al-rich zeolite-confined nanocluster catalysts is still a considerable challenge. In this paper, Cu@ZSM-5 (SiO 2 /Al 2 O 3 = 40) catalyst with Al-rich ZSM-5 zeolite-confined copper nanoclusters were designed and synthesized by the in-situ ligand-assisted hydrothermal crystallization method. The average size of the encapsulation metal clusters was only 2.3 nm after treatment at 400°C for 2 h in a hydrogen environment, which exhibits excellent thermal stability. 27Al MAS NMR and Pyridine-adsorbed IR (Py-IR) spectra confirmed that Al was successfully introduced into the zeolite framework. The intimate metal- Brønsted acidic site distribution enables complete conversion of furfuryl alcohol and 92.1 % selectivity of pentanediols. DFT calculations revealed that the high catalytic activity in catalyzing the ring opening of furfuryl alcohol to pentanediols could be attributed to the unique electronic effect in the Al-rich catalyst Cu@ZSM-5 (SiO 2 /Al 2 O 3 = 40). The in-situ ligand-assisted hydrothermal crystallization method will be very attractive regarding the simplicity required for industrial production. The Al-rich Cu@ZSM-5 (SiO 2 /Al 2 O 3 = 40) catalyst was endowed with rich and dense metal-Brønsted acidic sites by a simple in-situ synthesis method, providing a practical and feasible path for the high-value utilization of biomass molecules. Al-rich Cu@MFI catalyst encapsulating copper nanoparticles exhibits significant pentanediols selectivity and high anti-sintering performance in boosting furfuryl alcohol upgrading to pentanediols. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new Ni/Co 9 S 8 non-precious heterostructure electrocatalyst for alkaline hydrogen evolution electrocatalysis was fabricated. • An ultralow overpotentials of 76 mV for HER at 10 mA cm−2 in 1.0 M KOH was achieved on the optimized electrocatalyst. • The Ni/Co 9 S 8 @FP is able to maintain a current density of 100 mA cm−2 at 380 mV (vs. RHE) for 37 h. • The synergistic effect of Ni and Co 9 S 8 lead to the moderate hydrogen adsorption on Ni surface, thus improving the interfacial water dissociation. Hydrogen from electrolysis cell driven by sustainable electricity is one of the most clean and renewable energy sources. The design and synthesis of efficient and robust noble-metal-free electrocatalyst for hydrogen evolution reaction (HER) are of paramount importance in modern society. Herein, we developed a simple two-step strategy to construct a new Ni/Co 9 S 8 heterostructure using carbonised (900 °C) filter paper (FP) as a precious metal-free electrocatalyst for hydrogen evolution reaction (HER) in alkaline media. The optimized electrocatalyst can achieve an ultralow overpotentials of 76 mV for HER at 10 mA cm−2 in 1.0 M KOH. Moreover, it can be maintained a current density of 100 mA cm−2 at 380 mV (vs. RHE) for 37 h. More importantly, experimental and theoretical calculations reveal that the remarkable enhancement of HER activity could be attributed to the synergistic effect of Ni and Co 9 S 8 that lead to the moderate hydrogen adsorption on Ni surface and improve the water dissociation at the interface of Ni/Co 9 S 8. Our work paves a new pathway to design high-efficient electrocatalysts for massive hydrogen production. [Display omitted] [ABSTRACT FROM AUTHOR]

Developing cost‐effective and highly active hydrogen evolution reaction (HER) electrocatalysts is of pivotal importance in the roadmap of hydrogen economy. Increasing active sites and improving conductivity are two effective strategies to optimize the performance of electrocatalyst. In this paper, we report a highly active HER catalyst consisting of ultra‐small molybdenum carbide nanoparticles uniformly entrapped in mesoporous carbon microspheres (Mo2C@MCS) fabricated by in situ synthesis. In 1 M KOH, the catalyst exhibits an excellent HER performance with a pretty low overpotential (134 mV at current density of 10 mA cm−2) and a small Tafel slope (51 mV dec−1), which exceeded the currently reported un‐doped Mo2C catalyst. The excellent HER performance is attributed to the abundant active sites provided by the ultra‐small Mo2C nanoparticles as well as the superior conductivity originated from carbon matrix and the intimate contact between Mo2C nanoparticles and mesoporous carbon wall. [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]

Synthesis gas production is a technology that dates to the 1950s. Recently, the conversion of hydrocarbons to syngas has played an important role in various applications from gas-to-liquid (GTL) processes to fuel cell applications. However, the current industrial production method is only profitable when large quantities of syngas are produced and generates high amounts of CO2 as a by-product. With the growing demands for smaller-scale and mobile syngas production technology, the catalytic partial oxidation of hydrocarbons has become a promising alternative to the conventional methane steam reforming technology. With the infrastructure for production and distribution of many commercial fuels already in place, numerous studies have been done on conversion of these fuels into syngas. This paper reviews the research that has been done in the past decade on the catalytic partial oxidation of conventional fuels and biofuels. The challenges faced in catalyst development are described as well as solutions that have been proposed to address those challenges. Advances in kinetic modelling of catalytic partial oxidation are presented, and techniques used to develop such models have also been highlighted. Finally, research gaps have been identified and recommendations have been given for further investigations to address current challenges. [ABSTRACT FROM AUTHOR]

An effective and safe route is proposed to prepare supported Mo2C-based catalysts from organic–inorganic hybrids, which exhibit high activity and stability for producing H2from methanol catalytic decomposition. [ABSTRACT FROM AUTHOR]

The review paper accumulates the latest information on the analysis of catalyst synthesis for the electrolysis of water in alkaline and partially in acidic media. Literature data on the production of electro-catalysts based on noble, refractory, transition and pure metals, as well as metals doped with molybdenum, phosphorus, and other elements, are presented. Given the different methods of synthesis of electro-catalyst, the advantage of the electrochemical method is emphasized as easy, accessible method enabling to regulate the composition of synthesized electrodes by changing the content of an electrolyte and the conditions of electrolysis, controlling the properties of synthesized materials. [ABSTRACT FROM AUTHOR]

One of the most attractive routes for the production of hydrogen or syngas for use in fuel cell applications is the reforming and partial oxidation of hydrocarbons. The use of hydrocarbons in high temperature fuel cells is achieved through either external or internal reforming. Reforming and partial oxidation catalysis to convert hydrocarbons to hydrogen rich syngas plays an important role in fuel processing technology. The current research in the area of reforming and partial oxidation of methane, methanol and ethanol includes catalysts for reforming and oxidation, methods of catalyst synthesis, and the effective utilization of fuel for both external and internal reforming processes. In this paper the recent progress in these areas of research is reviewed along with the reforming of liquid hydrocarbons, from this an overview of the current best performing catalysts for the reforming and partial oxidizing of hydrocarbons for hydrogen production is summarized. [ABSTRACT FROM AUTHOR]

This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation. Under the same condition for reforming and combustion, the results demonstrate that higher methanol conversion is achievable in cross-U type reactor. However, it is also found in cross-U type reactor that methanol reforming selectivity is the lowest due to the decreased water gas shift reaction under high temperature, thereby carbon monoxide concentration is increased. Furthermore, the reformed gas generated from the reactors is fed into a high temperature proton exchange membrane fuel cell (PEMFC). In the test of discharging for 4 h, the fuel cell fed by cross-U type reactor exhibits the most stable performance. [ABSTRACT FROM AUTHOR]

The management of plastic wastes has become an urgent issue due to the overconsumption of single-use plastic products. As a promising avenue for plastic waste valorization, chemical recycling by converting plastics into value-added products has attracted tremendous attention. In this paper, the Fe-Ni alloy catalysts via in-situ exsolution were employed for the straightforward microwave plasma-initiated decomposition of plastic wastes for high yield H 2 and carbon nanotubes. The partial substitution of Fe by Ni promoted in-situ exsolution of alloy nanoparticles homogeneously. Specifically, characterization results showed that the introduction of Ni modulated metal-support interaction, which further affected the crystalline phase, nanoparticle size and oxygen vacancies. The exsolved Fe-Ni alloy catalyst exhibited the highest catalytic activity, over which 96 % hydrogen of plastic wastes rapidly evolved out in the form of gas products accompanied with high-purity carbon nanotubes. The H 2 yield was 415 mmol·g−1H plastic , which exhibited an over 2 times improvement versus the supported catalyst. Moreover, the successive cycle test displayed the potential for converting plastic wastes into H 2 -rich fuels and high-quality CNTs continuously. Generally, the in-situ exsolution strategy of Fe-Ni alloy catalysts contributed to the sustainable and high-efficient recycling of plastic wastes into H 2 -rich gas products and carbon nanotubes under microwave plasma. [Display omitted] • Partial substitution of Fe by Ni promoted in-situ exsolution of nanoparticles. • 96 % hydrogen was converted into gas fuels with H 2 yield of 415 mmol·g-1H plastic. • H2 yield of Fe 0.7 Ni 0.3 -Al 2 O 3 increased over 2 times versus the supported catalyst. • High quality CNTs were fabricated over exsolved Fe-Ni alloy catalyst continuously. [ABSTRACT FROM AUTHOR]

The liquid fuel gasification to obtain a clean flue gas for power generation and produce chemicals such as methanol is a most promising attempt to reduce the greenhouse gas emissions and air pollutants. In this paper, an equilibrium model of liquid fuel gasification was developed by the method of Gibbs free energy minimization. Two kinds of catalysts: Ni/CeO2/Al2O3and Ni/Al2O3were used to explore the influence of catalysts and operating conditions on hydrogen yield and char conversion. Over the ranges of operating conditions studied, the maximum hydrogen yield reached 52.47 vol%, whereas the char conversion varied between 45.2% and 98.5%. The results indicated that an appropriate reaction temperature is favorable for higher hydrogen production and char conversion. The model was validated with experimental data obtained from a fluidized bed gasifier. [ABSTRACT FROM PUBLISHER]

Molybdenum disulfide (MoS2), as a promising catalyst, has been widely investigated for hydrogen evolution reaction (HER). But the low density and poor reactivity of active sites, poor electrical transport, and inefficient electrical contact to the catalyst, leads to the modest performance. In this work, we demonstrate an effective route to overcome those issues by decorating the conductive LixMoS2 nanoparticles on the three-dimensional carbon fiber paper (CFP) through combining hydrothermal method and lithium intercalation. Thus, the dense LixMoS2 nanoparticles of the surface can provide the large number of exposed active sites, the highly-conductive LixMoS2 nanoparticles and CFP substrate can facilitate the transfer of electron not only between the LixMoS2 nanoparticles and CFP, but also between the whole sample and current collector, and the porous networked structure can enable the diffusion and penetration of electrolyte. Prompted by those advantage, the as-prepared samples exhibit outstanding HER catalytic activity with the small Tafel slope of 62 mv dec−1 and the low overpotential of −115.6 mV vs RHE at an electrocatalytic current density of 10 mA cm−2. Chronoamperometric current test for 10 h confirms the long-term stability of the catalyst. [ABSTRACT FROM AUTHOR]

In this paper, a simple method of NaHCO 3 reduction to CH 3 COOH in water with Al powder as a reductant on a commercially available Pd/C catalyst is described that producing CH 3 COOH with a good yield of 8% from NaHCO 3 on a carbon basis at 300 °C under hydrothermal conditions. A high adsorption enthalpy of C 1 intermediates on the Pd catalyst may act as an important role in the reduction of NaHCO 3 into CH 3 COOH on Pd/C catalyst. This research provides a simple way to convert the CO 2 into a C 2 compound. [ABSTRACT FROM AUTHOR]

Current energy systems have a significant environmental impact and contribute to the climate change. The future energy systems must call upon clean and renewable sources, capable of producing energy with low CO 2 emission, hence partly decarbonizing the energy sector. Producing H 2 by catalytic steam reforming of methanol (CSRM) is gaining interest for its specific applications in fuel cells, in a decentralized H 2 production, or to locally boost the heat content of e.g. natural gas. Supported metal catalysts enhance the endothermic steam-driven methanol conversion. The paper discusses the CSRM manufactures and assesses 2 novel, cheap and efficient catalysts (Co/α-Al 2 O 3 and MnFe 2 O 4). The performance of the Co/α-Al 2 O 3 catalyst is significantly superior to MnFe 2 O 4. The methanol conversion exceeds 95% with high H 2 yields (>2.5 mol H 2 /mol CH 3 OH) and low CO and CO 2 by-product formation. The methanol reaction is very fast and a nearly constant product distribution is achieved for gas-catalyst contact times in excess of 0.3 s. The catalyst maintains its efficiency and selectivity for several days of reaction. The hydrogen productivity of the Co/α-Al 2 O 3 is about 0.9 L H 2 g cat −1 h−1., nearly a fourfold of the MnFe 2 O 4 alternative. The different occurring reactions are combined in a kinetics analysis and demonstrate the high rate of reaction and the predicted product distribution. A catalytic sintered metal fleece reactor is finally developed, mostly in view of its integration with a solid oxide fuel cell (SOFC). The assessed CSRM system clearly merits further pilot plant research. • The catalytic steam reforming of methanol is investigated. • Co/α-Al 2 O 3 and MnFe 2 O 4 were used as catalysts. • The yield is about 2.5 mol H 2 /mol CH 3 OH. CO and CO 2 are by-products. • No catalyst coking is observed. • The reaction rate is very high: complete CH 3 OH conversion is achieved within 0.3 s. [ABSTRACT FROM AUTHOR]

Abstract: The paper deals with fluidized bed gasification of a biomass for producing a syngas with optimized hydrogen yield thanks to in-bed catalysis. Four different bed materials have been adopted: inert quartzite as reference case, olivine and dolomite as natural catalysts, and Ni-alumina as artificial catalyst. The gasification tests have been carried out at steady state in a pilot-scale bubbling fluidized bed, under operating conditions typical for gasification as reported in the paper. The gas analyses have been performed with dedicated instrumentation, like continuous analyzers and gas chromatograph, and adopting a standard protocol for tar sampling and characterization. The influence of the catalytic materials on the concentration of stable gases (e.g. H2, CO2, CO, CH4 and light hydrocarbons) as well as on the efficiency of tar conversion has been studied. In particular the artificial catalyst has the largest effectiveness in enhancing the H2 yield as well as in tar reduction. The catalyst gives rise to an elutriation rate significantly lower than that observed for dolomite at comparable U/U mf ratio, denoting a better mechanical resistance. A stable activity of the nickel–alumina catalyst has been observed for the whole duration of reaction tests suggesting that no deactivation phenomena occurred, due to coke deposition or morphological modifications of the particles. [Copyright &y& Elsevier]

Abstract: This is the third in a series of papers by our team on apparently anomalous Balmer series line broadening in hydrogen containing RF generated, low-pressure () plasmas. In this paper the selective broadening of the atomic hydrogen lines in pure and mixtures in a large general electronics conference (GEC)-type cell (36cm length ID) was mapped as a function of position, ratio, time, power, and pressure. Several observations regarding the selective line broadening were particularly notable as they are unanticipated on the basis of earlier models. First, the anomalous broadening of the Balmer lines was found to exist throughout the plasma, and not just in the region between the electrodes. Second, the broadening was consistently a complex function of the operating parameters, particularly gas composition (highest in pure position, power, and pressure. Clearly, not anticipated by earlier models were the findings that under some conditions the highest concentration of “hot” () hydrogen was found at the gas entry end, and not in the high-field region between the electrodes, and that in other conditions, the hottest H was at the (exit) pump (also grounded electrode) end. Third, excitation and electron temperatures (measured optically) were less than 1eV in all regions of the plasma not directly adjacent () to the electrodes, providing additional evidence that the energy for broadening, contrary to standard models, is not obtained from the electric field. Fourth, in contrast to our earlier studies of hydrogen/helium and water plasmas, we found that in some conditions 98% of the atomic hydrogen was in the “hot” state throughout the GEC-type cell. Virtually every operating parameter studied impacted the character of the hot H atom population. Clearly, second and third order effects exist, indicating a need for experimental design. Some non-field mechanisms for generating hot hydrogen atoms are outlined. [Copyright &y& Elsevier]

Abstract: This paper analyzes the mechanism of deactivation of a new Cu–Al2O3–CuAl2O4 water–gas shift (WGS) catalyst recently developed for small-scale hydrogen generation applications, such as fuel cell-based residential power generators and hydrogen fueling stations. The catalyst has good potential for use in small-scale fuel processors working under essentially steady-state conditions, such as on-site hydrogen generation systems for hydrogen filling stations. However, transient regimes with frequent starts and stops of the fuel processing system, common for the residential fuel cell applications, can result in aging with a decline in activity of this (and most likely of any) copper-based WGS catalyst. The study described in this paper reveals that the aging resulting in deactivation of Cu–Al2O3–CuAl2O4 under start–stop conditions is due to passivation of the catalytically active surface by the dense shell of hydrogen-bonded hydroxides strongly adsorbed over copper oxide crystallites. This deactivation phenomenon, likely to be typical for all copper-based WGS catalysts operating with frequent starts and stops, is a serious issue that will likely prevent use of such catalysts in residential fuel cell applications. However, the deactivated Cu–Al2O3–CuAl2O4 catalyst can be regenerated by calcining in air, with full recovery of the activity. This regeneration, which is impossible for conventional copper–zinc–alumina catalysts, is a significant practical advantage and also supports the conclusion on the role of surface hydroxides in the deactivation mechanism. [Copyright &y& Elsevier]

Abstract: Hydrogen for use in fuel cells is produced in a fuel processor by the catalytic reforming of hydrocarbons. Experimental results from synthetic diesel and JP8 autothermal reforming activity tests performed over a commercial Pt/ceria catalyst was presented in part I of this paper. A reversible–irreversible poisoning phenomenon affected the catalyst''s activity. The objective of this paper is to present the results of characterization studies on these catalysts. Temperature programmed reduction (TPR) studies suggest that the oxidation–reduction properties of ceria are affected by poisoning. Temperature programmed desorption (TPD) and XPS analysis confirmed the formation of chemisorbed sulfur entities (irreversible poisoning). Based on these findings, a global deactivation mechanism is proposed. Experiments confirmed that the poisoning is reversible and is enhanced at higher temperatures in presence of a reducing environment. [Copyright &y& Elsevier]

Abstract: Hydrocracking is widely practiced by the refiners to convert heavy petroleum feedstocks into desired lighter products. There are many process variables and catalyst formulations for optimization of hydrocracker performance with respect to yield pattern, products’ quality and catalyst life. A user-friendly steady state hydrocracker model (HC-MOD) has been developed based on novel continuum theory of lumping approach for simulating hydrocracking kinetics and heat effects in a commercial hydrocracker. The model formulation includes skewed Gaussian type primary yield distribution function to describe yield and selectivity of the hydrocracking components. The model provides excellent prediction of commercial units’ performance, as it incorporates hydrocracking kinetics of paraffins, naphthenes, and aromatics. The capabilities of HC-MOD include prediction of products’ yields and qualities, reactor bed temperature profile, estimation of chemical hydrogen consumption, etc. In the present paper, case studies from operating refineries are presented where HC-MOD has been successfully applied for optimization and troubleshooting, leading to better performance. The cases involve: (i) solving low conversion problem in a two stage hydrocracker, (ii) catalyst selection for maximum middle distillates, and (iii) increase in middle distillates selectivity through optimization of operating conditions. The paper also describes the knowledge-based solutions, which have led to the significant benefits to the operating refineries. [Copyright &y& Elsevier]

• Catalytic cracking of toluene with PDA porous carbon increases hydrogen production. • The concentration of activated steam has a positive influence on the surface area. • More C-O functional groups are more likely to have n-π interaction with toluene. Carbon-based metal catalysts have excellent catalytic performance due to their porous structure and high dispersion of metal particles. In this paper, polydopamine (PDA) microspheres as carbon supports and Fe as the metal phase are used to synthesize carbon-based nano-Fe catalysts for catalytic cracking of toluene. The PDA derived carbon-based metal catalysts has more regular spherical shape when compared with biomass derived catalyst. The effect of activation steam concentration and Fe load on the characteristics of catalyst have been studied. As the concentration of activated steam increases from 7.5% to 15%, the specific surface area of the carbon support increases significantly, and the number of micropores also increases. When the Fe impregnation concentration is less than 5%, the dispersion of the metal particles on the surface of the carbon support is very good, and when the Fe impregnation concentration is greater than 5%, the metal particles on the surface of the carbon support begin to agglomerate. The introduction of this catalyst can significantly increase the removal efficiency of toluene and the hydrogen content of tail gas. The carbon-based metal catalysts before and after the toluene catalytic cracking experiments are characterized and found that the microporous structure played an important role in the removal of toluene, and the C─O functional groups and ─OH groups on the catalyst surface also played an important role in the catalytic process. The addition of Fe species can increase the specific surface area and promote the formation of surface functional groups, and can also strengthen the π-π interaction and electrostatic interaction on the catalyst surface. The lattice oxygen introduced by iron oxide can provide oxygen source for the oxidation reaction of toluene. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the DME ATR reaction with different types of precious metal (Pt, Rh, Ru)-supported CGO catalysts. We also evaluated the reaction characteristics of DME ATR reaction by modifying certain reforming conditions, including the temperature, the amount of air and water, and the flow rate. The Ru-added CGO catalyst showed the best performance in DME ATR. The operating condition that produced the greatest effect on conversion efficiency was temperature; however the amounts of steam and air were also important with regard to conversion efficiency and the reaction heat. In case higher GHSV conditions the methane yields are increased. To maximize conversion efficiency with thermal neutral operating conditions, we suggest an SCR of 1.5, OCR of 0.45, over temperature of 700 °C, and a GHSV of less than 20,000/h. Under harsh conditions, such as low temperature and high GHSV, the methane yield increases. Therefore, the high temperature DME ATR reaction seems to consist of two main steps: the DME decomposition to methane and the methane autothermal reforming reaction. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NO x to nitrogen by hydrogen (H 2 -SCR) does not result in any secondary pollutants and can reduce NO x at the lowest possible temperatures. To achieve this goal, proper catalysts are critical. In this paper, NiFe 2− x Pd x O 4 catalysts were prepared using a sol–gel auto-ignition method for the selective catalytic reduction of NO with hydrogen (H 2 -SCR) in the presence of oxygen at 150–250 °C. The NiFe 2− x Pd x O 4 catalysts exhibited high SCR activity providing 100% NO conversion at 190 °C, and the activity improved as the palladium content increased. NiFe 1.90 Pd 0.10 O 4 exhibited a slightly lower activity in the 180–220 °C range. NiFe 1.93 Pd 0.07 O 4 and NiFe 1.95 Pd 0.05 O 4 exhibited larger acidity, higher level of reducibility and catalytic activity, which was validated through NH 3 -TPR, H 2 -TPR analysis and SCR activity tests. The XRD results indicated that the samples had a spinel cubic structure with good crystallization. The EDS results indicated that the Fe/Ni and Pd/Ni atomic ratio in the samples were consistent with the theoretical molecular formula (i.e., NiFe 2− x Pd x O 4 ). The effects of GHSV, H 2 /NO ratios and O 2 feed concentration on the NO conversion over the NiFe 1.95 Pd 0.05 O 4 catalyst were also investigated. An increase in the O 2 concentration from 0% to 6% and a decrease in the H 2 /NO ratio from 10:1 to 5:1 produced only a slight decrease in the NO conversion. Studies on the effect of 3% and 5% H 2 O on the SCR activity concluded that the slight activity decrease, was due to reversible inhibition and weakly irreversible deactivation, and that the catalysts contained excellent water tolerance. [ABSTRACT FROM AUTHOR]

The preparation, characterization, activity, and stability of a Ni–Al 2 O 3 catalyst derived from reduction of a Ni–Al layered double hydroxide precursor (LDH, Ni 6 Al 2 (OH) 16 (CO 3 ) 0.75 (OH) 0.25 ·4H 2 O) are reported in this paper. In-situ X-ray adsorption spectroscopy shows that reduction of Ni from the LDH precursor to form a highly loaded 80% Ni–Al 2 O 3 catalyst (Ni–Al 2 O 3 –LDH) is faster than reduction of a 10% impregnated Ni–Al 2 O 3 alumina (Ni–Al 2 O 3 –I) catalyst. The reduced Ni–Al 2 O 3 –LDH catalyst exhibits highly dispersed Ni nanoparticles (3–5 nm) distributed on top, partially embedded nanoparticles, and some encapsulated in the Al 2 O 3 matrix. The nanoparticles impregnated on alumina (Ni–Al 2 O 3 –I) are larger (∼7–15 nm) and appear on top of the alumina support. Conversion vs time on stream (TOS) results during ethanol decomposition at 250 °C on Ni–Al 2 O 3 –LDH exhibits only a slight deactivation during 100 h TOS, while the Ni–Al 2 O 3 –I catalyst shows rapid deactivation with no conversion after 2 h TOS. X-ray photoelectron spectroscopy shows that the carbon content increases up to 48% after 100 h TOS on the Ni–Al 2 O 3 –LDH catalyst, while a similar increase occurs after 2 h TOS on the Ni–Al 2 O 3 –I catalyst . TEM shows that after 100 h TOS either a thin layer of amorphous carbon or carbon nanotubes forms on Ni on top of the alumina matrix and on partially embedded Ni nanoparticles on the Ni–Al 2 O 3 –LDH catalyst. Total surface area of the Ni–Al 2 O 3 –LDH catalyst increased during TOS, which may be suplying fresh surface Ni from the encapsulated Ni nanoparticles that sustain the high activity. [ABSTRACT FROM AUTHOR]