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• 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]

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]

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]

Nowadays, hydrogen is gaining attention as one of the green energy alternatives within transition to a zero-emission economy. Increasing demand for hydrogen and its production has prompted the development of low-carbon strategies and technologies for hydrogen generation from hydrocarbons. This paper provides a thorough analysis of traditional and innovative methods for hydrogen production from fossil feedstock, reviewing the critical aspects and recent advancements in the field. The paper emphasizes the potential of in situ hydrogen generation as the most promising method, taking into account CO2 emission concerns. Additionally, this study explores the use of software packages for modeling hydrogen production, outlining their advantages and disadvantages and proposing the most favorable software for in situ hydrogen generation from hydrocarbons. Subsequent analysis sheds light on the effectiveness, economic viability, environmental impact, and future perspectives of various hydrogen production technologies. • Overview of hydrogen production technologies: conventional and innovative methods. • Key issues and best practices of the latest experimental and numerical studies. • Comparative analysis of various hydrogen production technologies and approaches. • Subsurface hydrogen generation has a great development potential. • There are methods for clean hydrogen production from hydrocarbon feedstock. [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]

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 work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show an improved stability towards the mechanical degradation of the MoSx catalyst. [ABSTRACT FROM AUTHOR]

In this paper, the experimental research on high-efficiency ortho-para (O-P) hydrogen conversion is carried out. By designing and building a low-temperature O-P hydrogen conversion experimental device, the low-temperature catalytic conversion and pressure drop flow characteristics are studied. The experimental data show that under the same conditions, the catalytic performance of iron hydroxide is the best among the three iron-based catalysts, and the hydrogen flow rate is an important factor affecting the conversion efficiency. The pressure drop formula for the porous region filled with catalyst suitable for the experimental device is proposed. This study has reference significance for the design of high-efficiency O-P hydrogen converter and the optimization design of hydrogen liquefaction process. [ABSTRACT FROM AUTHOR]

This work describes a new well-defined, air-stable, phosphine free palladium(II) [Pd(L)Cl] (1) catalyst. This catalyst was utilized for N-alkylation of amines and indole synthesis where H2O was found to be the by-product. A broad range of aromatic amines were alkylated using this homogeneous catalyst with a catalyst loading of 0.1 mol%. Greener aromatic and aliphatic primary alcohols were utilized and a hydrogen auto-transfer strategy via a metal–ligand cooperative approach was investigated. The precursor of the antihistamine-containing drug molecule tripelennamine was synthesized on a gram scale for large-scale applicability of the current synthetic methodology. A number of control experiments were performed to investigate the possible reaction pathway and the outcomes of these experiments indicated the azo-chromophore as a hydrogen reservoir during the catalytic cycle. [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]

The synthesis of a 90% Ni/Al2O3 catalyst via solution combustion synthesis with various fuels was studied in this work. Catalysts with a high content of the active component (i.e., nickel) were obtained as a result of the combustion of Ni(NO3)2·6H2O and Al(NO3)3·9H2O mixtures with fuel. The fuels, such as hexamethylenetetramine, glycine, urea, starch, citric acid, and oxalic acid, were investigated. The synthesis was carried out in a furnace, with the temperature being raised from room temperature to 450 °C at a rate of 1 °C per min. The paper evaluates the efficiency of fuels and their effect on the structure and properties of catalysts, as well as their catalytic activity. The catalyst was used for the synthesis of hydrogen and carbon nanofibers by methane decomposition at 1 bar and 550 °C. The catalysts were tested in a vertical flow reactor without preliminary reduction. The obtained samples of catalysts and carbon nanomaterials were studied by transmission electron microscopy, low-temperature nitrogen adsorption, and X-ray diffraction. The highest activity of the catalyst was obtained when citric acid was used as a fuel. The specific yields of hydrogen and carbon nanofibers were 17.1 mol/gcat and 171.3 g/gcat, respectively. Catalytic decomposition of methane led to the formation of cup-stacked carbon nanofibers. [ABSTRACT FROM AUTHOR]

A new method for the generation of benzyl radicals from terminal aromatic alkynes has been developed, which allows the direct cross coupling with acrylate derivatives. Our additive-free protocol employs air-stable diamino Mo3S4 cubane-type cluster catalysts in the presence of hydrogen. A sulfur-centered cluster catalysis mechanism for benzyl radical formation is proposed based on catalytic and stoichiometric experiments. The process starts with the cluster hydrogen activation to form a bis(hydrosulfido) [Mo3(μ3-S)(μ-S)(μ-SH)2Cl3(dmen)3]+ intermediate. The reaction of various aromatic terminal alkynes containing different functionalities with a series of acrylates affords the corresponding Giese-type radical addition products. [ABSTRACT FROM AUTHOR]

In this paper, the catalyst tube lifetime of a practical steam methane reformer is analyzed numerically. The effect of burner operating mode on the flow development, hydrogen yield, and catalyst tube lifetime is discussed, with the aim of improving the reformer performance. The results of this study reveal that using the periodic boundary conditions, the temperatures and hydrogen yields obtained are much lower than the experimental values and the pressures are much lower than those using the real model. This results in overestimating the catalyst tube lifetime and underestimating the reformer operation risk. The catalyst tubes in the downstream area have longer lifetimes, while those in the upstream area have shorter lifetimes. Turning the upstream burners off is more efficient to the catalyst tube lifetime, while turning off the central groups of burners is less efficient. The main drawback of turning off burners is the decrease of hydrogen yield. [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]

It was the constant pursuit of researchers to explore catalysts with higher catalytic activity, and the use of co-catalysts to modify the performance of photocatalytic materials had a significant effect on charge separation. In this paper, the non-precious metal NiS-modified ZnCo2O4 composite catalytic material prepared by hydrothermal method had high-efficiency catalytic performance. When the weight ratio of NiS to ZnCo2O4 was 12%, the optimal catalytic activity is 3.57 mmol g−1 h−1, which was more than twice that of ZnCo2O4. The presence of NiS not only improved the specific surface area of the catalyst and its ability to respond to light, but the close interface formed by the combination of the two monomer phases accelerated the transfer and the utilization of the photocharge on ZnCo2O4 to NiS, thereby promoting the separation of electron holes and improving the photocatalytic activity of the catalyst. According to the research results, the mechanism of hydrogen production in the photocatalytic system was revealed. In this paper, NiS was used to modify the bimetallic oxide with cubic appearance, which provided a new strategy for the development of new photocatalysts. [ABSTRACT FROM AUTHOR]

One-pot three-component synthesis of α-methylated ketones from secondary and primary alcohols via a triple dehydrogenative method is presented here. This protocol uses a polystyrene-supported catalyst and the catalyst is reused for five runs without any drop in its activity. Detailed mechanistic investigation was carried out with control reactions and deuterium labelling experiments revealed that secondary and primary alcohols act as a hydrogen source in this one-pot synthesis of α-methylated substituted ketones. [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]

The hydrogen evolution reaction (HER) is a complex reaction involving many interdependent physicochemical steps. Highly ordered carbon nitride‐based materials, such as Na‐PHI and K‐PHI, display some of the highest activities for H2 evolution among the carbon nitride‐based materials, due to their electronic properties, but also the presence of cyanimide terminations, which favors the charge transfer for the Pt cocatalyst nanoparticles (NPs). For such highly optimized semiconductor structures, the necessity to control and improve other steps of the photocatalytic process becomes essential, in particular the poor electron transfer from the Pt NPs to the protons in solution over the Helmholtz or Stern layer. Taking highly ordered Na‐PHI as a test material, the influence of water‐dissolved alkali cations on the HER is systematically studied and it is experimentally verified that the electron transfer from the Pt NPs to the protons in solution limits the efficiency of heterogeneous carbon nitride‐based catalysts. This paper explains how hydrated alkali cations influence electron transfer and are able to boost the H2 evolution rate of the same Na‐PHI from 2401 up to 5330 µmol h−1 g−1 with an apparent quantum yield of 13% at 420 nm. [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]

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]

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]

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 work, an innovative route for upgrading biomass-derived phenolic monomers by "hydrogen-free" hydrodeoxygenation (HDO) was proposed and evaluated. The HDO process was integrated with the activation of water and aqueous phase reforming of in situ generated methanol over a nano-porous Ni catalyst and finally the one-pot approach was established achieving high selectivity of bio-phenol. DFT calculations confirmed the crucial role of the Ni catalyst in the activation of water and the following HDO process. The study of the reaction pathway and the mechanism showed that the initial hydrogen source came from water splitting on the surface of the Ni catalyst, which triggered the fracture of the aromatic ether bond to afford phenol and methanol. The subsequent aqueous phase reforming of methanol generated more hydrogen and further accelerated the HDO process. Under the optimized conditions the conversion of guaiacol reached 41.5% and the selectivity of phenol can be 100% at 160 °C. On further increasing the temperature to 190 °C, a high conversion of 96.3% could be achieved while maintaining the selectivity of phenol to 77.9%. After a smart design of methanol release during the reaction, the conversion and selectivity could be further improved to 90.5% and 90.3%, respectively. Overall, the proposed method demonstrates the feasibility of upgrading oxygen-containing biological compounds in a neat water system integrating chemo-splitting of water with using endogenous hydrogen for self-hydrolysis inhibiting external hydrogen supply. [ABSTRACT FROM AUTHOR]

The importance of photocatalytic hydrogen evolution is increasing in energy research and environmental catalysis. Co-MOF, a metal–organic framework compound with a zeolite topological structure, has the advantage of being a semiconductor in photocatalytic applications. The new composite materials constructed by coupling Co-MOF with traditional semiconductors will significantly stimulate the potential of photocatalysis due to the construction of a heterogeneous interface. We accurately controlled the growth of Co-MOF with different morphologies by adjusting the ratio of raw materials. With the increase of dimethylimidazole, hexagonal prism morphology (Co-MOF-H), leaf morphology (Co-MOF-B), and Daisy morphology (Co-MOF-D) were successively synthesized. The experimental results show that H-g-C3N4 has the best catalytic activity when adsorbing hexagonal prism Co-MOF. When the ratio of H-g-C3N4 reached 125 mg, the optimal hydrogen evolution activity reached 1033 μmol g−1 h−1. Various characterization methods were used to explain the influence of morphology regulation on the hydrogen evolution ability of Co-MOF and explore the mechanism of hydrogen evolution of Co-MOF/H-g-C3N4 composite catalysts. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [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, 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]

As a narrow bandgap semiconductor, transition metal selenides are promising as excellent electrocatalysts for hydrogen evolution reactions (HERs). Herein, using an ultra-thin MOF as the precursor, a Co-doped core–shell shaped NiSe2 based catalyst is successfully constructed by a two-step calcination method as an efficient HER catalyst. Experiments and theoretical calculations indicate that the introduction of Co adjusts the electronic structure of Ni and Se, promoting charge transfer and reducing the energy barrier of the rate-limiting step to accelerate the hydrogen precipitation reaction. In addition, the core–shell structure contributes to mass transport, and the outer carbon layer improves the stability of the catalyst. The optimal catalyst (Ni0.75Co0.25Se2@NC) exhibited satisfactory electrocatalytic activity as evidenced by a low overpotential of −143 mV at a current density of −10 mA cm−2 and a small Tafel slope of 37.5 mV dec−1. This work provides a valuable strategy for fabricating efficient NiSe2 based electrocatalysts for the HER. [ABSTRACT FROM AUTHOR]

In this contribution, a simple method for the screening of photocatalytic activity of catalyst materials is presented. The method is based on two steps: the immobilization of the photocatalyst and the subsequent testing of their photocatalytic activity, using the gas evolution at the solid‐liquid interface. Up to four catalysts can be tested under the same conditions. The observed gas evolution for selected photocatalysts is consistent with trends reported in the literature from conventional photocatalytic reactors. [ABSTRACT FROM AUTHOR]

Hydrogen spillover effect has recently garnered a lot of attention in the field of electrocatalytic hydrogen evolution reactions. A new avenue for understanding the dynamic behavior of atomic migration in which hydrogen atoms moving on a catalyst surface was opened up by the setup of the word "hydrogen spillover." However, there is currently a dearth of thorough knowledge regarding the hydrogen spillover effect. Currently, the advancement of sophisticated characterization procedures offers progressively useful information to enhance our grasp of the hydrogen spillover effect. The understanding of material fabrication for hydrogen spillover effect has erupted. Considering these factors, we made an effort to review most of the articles published on the hydrogen spillover effect and carefully analyzed the aspect of material fabrication. All of our attention has been directed toward the molecular pathway that leads to improve hydrogen evolution reactions performance. In addition, we have attempted to elucidate the spillover paths through the utilization of DFT calculations. Furthermore, we provide some preliminary research suggestions and highlight the opportunities and obstacles that are still to be confronted in this study area. [ABSTRACT FROM AUTHOR]

The bulk and surface properties of materials based on nickel and aluminum oxides and hydroxides, as such or after reduction processes, are reviewed and discussed critically. The actual and potential industrial applications of these materials, both in reducing conditions and in oxidizing conditions, are summarized. Mechanisms for reactant molecule activation are also discussed. [ABSTRACT FROM AUTHOR]

The Front Cover shows the reaction pathway of n‐octanol oxidation over supported nanogold catalysts in front green leaves and the outline of chemical plant. In their Full Paper, E. Pakrieva et al. investigated the combined influence of gold content, modifying additives and redox pretreatments on catalytic properties and formation of active sites of Au/TiO2 in the selective oxidation of n‐octanol under mild conditions. They found that the order of catalytic activity depended on the support nature for all treated samples. The catalytic activity increased with the increase of gold loading in the samples with hydrogen pretreatment, while after the oxidative pretreatment of the catalysts the opposite dependence of the activity with the gold content was found. This catalytic behavior was explained by a change in the surface concentration of monovalent gold ions, which seemed to be the active sites. More information can be found in the Full Paper by E. Pakrieva et al. on page 1615 in Issue 6, 2019 (DOI: 10.1002/cctc.201801566). [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]

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]

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Dry reforming is a very interesting process for synthesis gas generation from CH4 and CO2 but suffers from low hydrogen yields due to the reverse water-gas shift reaction (WGS). For this reason, membranes are often used for hydrogen separation, which in turn leads to coke formation at the process temperatures suitable for the membranes. To avoid these problems, this work shows the possibility of using nickel self-supported membranes for hydrogen separation at a temperature of 800 °C. The higher temperature effectively suppresses coke formation. The paper features the analysis of the dry reforming reaction in a nickel membrane reactor without additional catalyst. The measurement campaign targeted coke formation and conversion of the methane feedstock. The nickel approximately 50% without hydrogen separation. The hydrogen removal led to an increase in methane conversion to 60-90%. [ABSTRACT FROM AUTHOR]

The development of efficient and low-cost catalysts is of great significance for the future application of the electrocatalytic hydrogen evolution reaction (HER). Herein, a series of Ni,N co-doped Mo2C nanostructures (Nix–Mo2C/N) with different Ni content levels are fabricated. The phase-directing effect of Ni on Mo2C/N is observed, which is in charge of the phase transformation of Mo2C/N from an α- to a β-phase. At the optimized Ni-doping level, biphase Ni15–Mo2C/N exhibits outstanding HER activity under both acidic and alkaline conditions. In particular, under alkaline conditions, Ni15–Mo2C/N delivers an overpotential of only 105.0 mV, accompanied by a low Tafel slope of 44.96 mV dec−1. The performance is comparable to commercial 20% Pt/C and higher than most state-of-the-art Mo2C-based catalysts as well. [ABSTRACT FROM AUTHOR]

Recently, much attention has been focused on the development of photocatalysts for hydrogen evolution. Up to now, efficient hydrogen generation is still greatly challenging due to the restraints of the surface redox reaction rate, and the introduction of a co-catalyst is one of the keys to this problem. Here, dual non-noble co-catalysts NixP and Mn3O4 were proposed and prepared on a g-C3N4/red phosphorus (CNP) hybrid structure with a high light adsorption capability by a two-step photo-deposition method. The photo-excited charge on the composite catalyst separate and transfer from C3N4 to red phosphorous due to a type I heterojunction structure. NixP and Mn3O4 act as reductive and oxidative co-catalysts, respectively. The hydrogen production rate was 5851.3 μmol g−1 h−1, 12.4 times that of pure CNP. The consistent catalytic activity in an actual 25 mL flask for hydrogen evolution over eight hours accumulated 245.08 μmol H2 under solar simulated irradiation. This work provides practical reference for the development of a novel inexpensive photocatalyst system. [ABSTRACT FROM AUTHOR]

Currently, two-dimensional (2D) layered transition metal chalcogenides (TMCs), especially MoS2, are attracting widespread attention in the field of water electrolysis. Unfortunately, the catalytic activity of MoS2 is limited to a few edge sites and by its low conductivity. Herein, MoS2/NiS heterostructures possessing a flower-like morphology were constructed via an accurate thermal treatment process to realize precise interface modification. As expected, through the adjunction of a certain amount of polyvinylpyrrolidone, NiS grew uniformly on the surface of MoS2 nanosheets, thereby forming a large number of visual lattice fringes with a specific interplanar spacing, which promoted a higher electron-transfer efficiency. The better electron-transfer efficiency resulted in a better hydrogen evolution reaction performance, providing an overpotential of 158 mV at 10 mA cm−1, a Tafel slope of 128.1 mV dec−1, and significantly long-term durability. Moreover, density functional theory calculation also showed that the precise interface modification of MoS2/NiS heterostructure exhibited more occupations at the Fermi level, which improved the electrical conductivity. Additionally, the MoS2/NiS catalysts achieved a moderately lower hydrogen adsorption energy (ΔGH*), indicating that it had better catalytic hydrogen evolution performance. This work can be extended to design other catalytic materials and for understanding reactions in the fields of energy conversion through theoretical calculations. [ABSTRACT FROM AUTHOR]

Highlights: This review systematically summarizes the source of electricity, the key choice of catalyst, and the potentiality of electrolyte for prospective hydrogen generation. Each section provides comprehensive overview, detailed comparison and obvious advantages in these system configurations. The problems of hydrogen generation from electrolytic water splitting and directions of next-generation green hydrogen in the future are discussed and outlooked. Green hydrogen from electrolysis of water has attracted widespread attention as a renewable power source. Among several hydrogen production methods, it has become the most promising technology. However, there is no large-scale renewable hydrogen production system currently that can compete with conventional fossil fuel hydrogen production. Renewable energy electrocatalytic water splitting is an ideal production technology with environmental cleanliness protection and good hydrogen purity, which meet the requirements of future development. This review summarizes and introduces the current status of hydrogen production by water splitting from three aspects: electricity, catalyst and electrolyte. In particular, the present situation and the latest progress of the key sources of power, catalytic materials and electrolyzers for electrocatalytic water splitting are introduced. Finally, the problems of hydrogen generation from electrolytic water splitting and directions of next-generation green hydrogen in the future are discussed and outlooked. It is expected that this review will have an important impact on the field of hydrogen production from water. [ABSTRACT FROM AUTHOR]

In this paper, the 0.1 mol·L−1 FeSO4, NiSO4 mix-solution and 4 mol·L−1 NaOH solution were prepared by FeSO4·7H2O, NiSO4·6H2O and NaOH as raw materials. The Ni-Fe precursor nano-powders were prepared by chemical co-precipitation. The reaction conditions were that dropping speed 50 ml·min−1, pH value of reacting terminal 12, stirring speed 1200 r·min−1, reacting temperature 20°C, and reacting time 40 min. The shape of Ni-Fe precursor nano-powders were nano-stick and nano-ball. Length of Fe50Ni50 precursor nano-stick was 100–150 nm, diameter was 10–30 nm. Diameter of Fe50Ni50 precursor nano-ball was 10–50 nm. The Fe50Ni50 alloy nano-powders were prepared with materials Fe50Ni50 composite oxide by hydrogen co-reduction in closed circular system. The process conditions were that reduction temperature 600°C, reduction time 30 minutes. The Fe50Ni50 alloy nano- powders size was less than 100 nm. [ABSTRACT FROM AUTHOR]

The reduction process of NOx species stored over Pt-Ba/Al2O3 Lean NOx Trap systems is analysed in this paper when H2 is used as a reductant. The effect of different experimental conditions (temperature, reductant concentration, adsorption lengths, etc.) is addressed and discussed in relation to the selectivity and the efficiency of the reduction process. [ABSTRACT FROM AUTHOR]

Benzothiazole‐doped porous organic polymers (POP‐MBTS) were synthesized from a copolymerization reaction of 2‐(6‐(4‐vinylphenyl)pyridin‐2‐yl)benzo[d]thiazole with divinylbenzene. The corresponding POP‐MBTS‐Ir was obtained and fully characterized using SEM, TEM, EDS, TGA, XPS, and N2 sorption isotherms, which disclosed that this catalyst has a high surface area, hierarchical porosity, and thermodynamic stability. Importantly, this catalyst revealed a high catalytic activity for ten different kinds of borrowing hydrogen and dehydrogenation reactions in water with a good recovery performance. Furthermore, mechanistic investigations were conducted for the synthesis of triazine derivatives. [ABSTRACT FROM AUTHOR]

The first Pd2+ containing polyoxoniobate [Pd(cyclam)]5{H3Nb6O19}2 ⋅ 26H2O (I) was prepared at room temperature. In the structure, two hexaniobate clusters are surrounded by a bi‐capped cube formed by Pd2+ centered complexes. This motif is arranged in a layer‐like fashion with crystal water molecules located between cations and anions. Temperature resolved in‐situ X‐ray diffraction experiments demonstrate that successive removal of the crystal water molecules leads to formation of several crystalline intermediate phases. Water sorption investigations show that thermally removed H2O can be successfully reintegrated proceeding via two distinct steps. The catalytic performance for the light‐driven hydrogen evolution reaction (HER) was investigated in a sacrificial system and fluorescein Na+ salt as sensitizer yielding a high value of 90 μmol/h H2. Surprisingly, a composite Pd@Na7[HNb6O19] ⋅ 15H2O is in‐situ formed during the catalytic reaction by cation exchange with simultaneous reduction of Pd2+ nanoparticles decorating the hexaniobate support. The recovered catalyst was even more active producing 157 μmol/h H2 with an apparent quantum efficiency of 1.85 %. Photocatalytic experiments performed with ex‐situ generated Pd nanoparticles deposited on Na7[HNb6O19] ⋅ 15H2O show much lower activities indicating a synergistic effect of the in‐situ generated Pd@Na7[HNb6O19] ⋅ 15H2O catalyst. [ABSTRACT FROM AUTHOR]

A synergistic combination of photoredox and polarity reversal catalysis enabled a hydrogen evolution cross-coupling of silanes with H2O, alcohols, phenols, and silanols, which afforded the corresponding silanols, monosilyl ethers, and disilyl ethers, respectively, in moderate to excellent yields. The dehydrogenative cross-coupling of Si–H and O–H proceeded smoothly with broad substrate scope and good functional group compatibility in the presence of only an organophotocatalyst 4-CzIPN and a thiol HAT catalyst, without the requirement of any metals, external oxidants and proton reductants, which is distinct from the previously reported photocatalytic hydrogen evolution cross-coupling reactions where a proton reduction cocatalyst such as a cobalt complex is generally required. Mechanistically, a silyl cation intermediate is generated to facilitate the cross-coupling reaction, which therefore represents an unprecedented approach for the generation of silyl cation via visible-light photoredox catalysis. [ABSTRACT FROM AUTHOR]