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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]

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]

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 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 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]

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]

Due to inefficient charge separation and low surface catalytic conversion efficiencies, cocatalysts are required for achieving photocatalytic hydrogen evolution. Being a noble‐metal‐free cocatalyst, metallic 1T‐WS2 with excellent conductivity can function for this reaction. Herein, 1T‐WS2/Zn0.5Cd0.5S is constructed via a simple and feasible grinding approach. The composite containing 7.5 % 1T‐WS2 in 1T‐WS2/Zn0.5Cd0.5S achieves a hydrogen evolution rate of 61.65 mmol g−1 h−1 and an external quantum efficiency of 8.04 % at 420 nm, which is 37 times that of bare Zn0.5Cd0.5S (1.67 mmol g−1 h−1). The electrical conductivity of metallic 1T‐WS2 reduces the transfer impedance at the interface and thus accelerates the non‐radiative energy transfer and electron transport rate. The different Fermi levels of 1T‐WS2 and Zn0.5Cd0.5S form a Schottky junction, which promotes the transfer of photogenerated electrons from Zn0.5Cd0.5S to 1T‐WS2. More importantly, the close interface contact between 1T‐WS2 and Zn0.5Cd0.5S results in strong electron interactions, which is conducive to the spatial separation of photogenerated electrons and holes. This work will further expand the application of 1T‐WS2 in the photocatalytic hydrogen evolution process. [ABSTRACT FROM AUTHOR]

The thermal degradation and conversion of waste polyethylene (PE) using a two‐step process including hydrothermal oxidation (HO) and aqueous phase reforming (APR) were investigated. The objective of this study was to achieve efficient disposal of waste PE and generate H2 in a mild and green way. The effects of various HO conditions on both HO and APR processes were studied. A high H2O2 concentration caused overoxidation of PE resulting in more CO2. Decreasing the H2O2 concentration weakened the overoxidation. The process using diluted H2O2 exhibited the highest selectivity for acetic acid among the produced carboxylic acids. When the HO temperature exceeded 200 °C, there was an increase in the CO2 yield during the HO process and a decrease in the H2 yield during the APR process. In addition, the effects of various monometallic and bimetallic catalysts on the reforming of the aqueous phase from the HO of PE were discussed. The highest H2 mole fraction (51.52 %) in gaseous products from the APR process was obtained with Ru/mesoporous carbon. Nevertheless, Ru−Ni exhibited a higher stability than the monometallic Ru catalyst. [ABSTRACT FROM AUTHOR]

The strong desire for a circular economy makes obtaining fuels and chemicals via plastic degradation an important research topic in the 21st century. Here, the first example of the H2‐free polyethylene terephthalate (PET) conversion to BTX (benzene, toluene and xylene) was achieved by unlocking hidden hydrogen in the ethylene glycol part over Ru/Nb2O5 catalyst. Among the whole process (hydrolysis, reforming and hydrogenolysis/decarboxylation), the parallel hydrogenolysis and decarboxylation were competing and the rate‐determining step. Ru/Nb2O5 exhibited superior hydrogenolysis and poorer decarboxylation performance in direct comparison with Ru/NiAl2O4, accordingly contributing to the distinct selectivity to alkyl aromatics among BTX. Ru species on Nb2O5, unlike those on NiAl2O4, showed more Ruδ+ species owing to the strong interaction between Ru and Nb2O5, restricting the undesired decarboxylation. Along with NbOx species for C−O bond activation, excellent reactivity towards the H2‐free conversion of PET back to BTX with alkyl aromatics as dominant species was achieved. This H2‐free system was also capable of converting common real PET plastics back to BTX, adding new options in the circular economy of PET. [ABSTRACT FROM AUTHOR]

One‐dimensional materials exhibit fascinating properties in electrocatalytic applications but their fabrication faces the challenge of tedious and complicated operations. We have developed a bottom‐up strategy to construct a 1D metal carbide catalyst (Mo2C@NC) consisting of ultrafine Mo2C nanoparticles embedded within nitrogen‐doped carbon layers by simply calcining a mixture of ammonium molybdate, urea and melamine. Experimental results and thermodynamic calculations demonstrate that the retainable pyrolysis‐generated self‐supporting atmosphere plays a crucial role in the crystalline phase and morphology of materials. When functioned as an electrocatalyst for the hydrogen evolution reaction (HER), the achieved Mo2C@NC presents an excellent catalytic activity as well as outstanding stability. This work could shed fresh light onto the facile synthesis of effective HER catalysts with 1D nanostructure. [ABSTRACT FROM AUTHOR]

Molecular ruthenium cyclopentadienone complexes were employed for the first time as pre‐catalysts in the homogeneously catalysed Aqueous Phase Reforming (APR) of glucose. Shvo's complex resulted the best pre‐catalyst (loading 2 mol %) with H2 yields up to 28.9 % at 150 °C. Studies of the final mixture allowed to identify the catalyst's resting state as a mononuclear dicarbonyl complex in the extracted organic fraction. In situ NMR experiments and HPLC analyses on the aqueous fraction gave awareness of the presence of sorbitol, fructose, 5‐hydroxymethylfurfural and furfural as final fate or intermediates in the transformations under APR conditions. These results were summarized in a proposed mechanism, with particular emphasis on the steps where hydrogen was obtained as the product. Benzoquinone positively affected the catalyst activation when employed as an equimolar additive. [ABSTRACT FROM AUTHOR]

Gas sponges capable of absorbing, storing, and releasing ions in a reversible manner are in high demand for advanced electronics, energy devices, and sensors. Here, it is shown that brownmillerite BaInO2.5 epitaxial films exhibit the capability to act as solid‐state catalytic hydrogen sponges at a remarkably low temperature (≈100 °C). Compared to sintered pellets with random crystallographic orientations and many defects, BaInO2.5 epitaxial films give three orders of magnitude higher conductivity of hydrogen ions, which can be linked to the presence of well‐ordered 1D channels and lack of grain boundaries and other defects. Using scanning transmission electron microscopy, it is shown that hydrogen ions can be stored near InO4 tetrahedral layers of brownmillerite without destroying the parent framework. The high performance and reproducibility of the BaInO2.5 epitaxial films coupled with ultralow power consumption make them ideal candidates for neuromorphic devices and beyond. [ABSTRACT FROM AUTHOR]

Preferential oxidation of CO (CO‐PROX) in the hydrogen‐rich stream has been carried out over Pt‐NaY catalysts containing various Pt loadings along with Fe, Co, and Au. Catalysts have been characterized with inductively coupled plasma‐atomic emission spectroscopy, Brunauer, Emmett, and Teller surface area, X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, temperature programmed reduction, and Pt dispersion. CO‐PROX activities and CO oxidation selectivities are observed to increase with an increase in Pt content. Pt‐NaY catalyst with 0.75 wt.% Pt loading shows maximum CO‐PROX activity at low temperatures. An increase in space velocity decreases the CO and O2 conversions, but CO oxidation selectivity increases. A decrease in activity is observed when reformat gas contains around 20% H2O. During the stability test, no change in CO and O2 conversions is observed, but a small increase in the CO oxidation selectivity is noticed after 10 h indicating that the Pt‐NaY catalyst is a promising candidate for CO‐PROX reaction in a hydrogen‐rich stream. The Pt‐Fe‐NaY catalyst shows better activity than the Pt‐NaY catalyst but starts deactivating after 10 h. However, activity is observed to decrease over Pt‐Co‐NaY and Pt‐Au‐NaY catalysts. Pt‐Fe‐NaY catalyst with 0.75 and 0.35 wt.% Pt and Fe, respectively, shows better CO‐PROX activity at a temperature of 75°C. [ABSTRACT FROM AUTHOR]

The interaction of molecular hydrogen with ceria is of important relevance for heterogeneous catalysis related to green chemistry and renewable energy. Here, the complex structural transformations of a well-defined cerium oxide model catalyst are followed in situ and in real time when exposed to a reactive H2 environment. By using electron spectromicroscopy and diffraction with chemical and structural sensitivities, it is demonstrated that the transition from CeO2 to crystalline Ce2O3 occurs through a mixture of transient, coexisting phases on the nanoscale. The findings establish a clear relationship between structure and functionality for hydrogen dissociation over ceria(111), bearing profound implications on the nature of the reduction (Ce4+ → Ce3+) and mechanism for H2 scission. [ABSTRACT FROM AUTHOR]

A Crabtree-type IrI complex tagged with a fluorescent dye (bodipy) was synthesized. The oxidative addition of H2 converts the weakly fluorescent IrI complex ( Φ=0.038) into a highly fluorescent IrIII species ( Φ=0.51). This fluorogenic reaction can be utilized for the detection of H2 and to probe the oxidative addition step in the catalytic hydrogenation of olefins. [ABSTRACT FROM AUTHOR]

A fundamental problem of catalytic hydrogenation is the activation of H2, which is usually believed to occur through the interactions between H2 and the active center of a catalyst. In the present study, we show that H2 can be activated by chemisorbed C2H2 acting as a substrate molecule. This mechanism can occur when it is unfavorable for H2 to approach the metal‐center of the catalyst, which is caused by relatively strong adsorption C2H2. We demonstrate the proposed mechanism on various single/dual atom catalysts to establish a linear scaling relation generalizing the trend of H2 activation by C2H2. We also show that Ir‐doped graphene is a promising catalyst for the semi‐hydrogenation of C2H2 where H2 is preferably activated by the chemisorbed C2H2. The calculated turnover frequency reaches 0.076/s at 423 K and the selectivity to C2H4 approaches 100 %. The present study sheds light on mechanistic study of heterogeneous hydrogenation catalysts. [ABSTRACT FROM AUTHOR]

A novel Zn−Fe flow battery featuring an Fe3+ reduction reaction (Fe3+RR)‐coupled zinc oxidation, and an Fe2+ oxidation reaction (Fe2+OR)‐coupled hydrogen evolution reaction (HER) system as well, was established. This battery is capable of driving two Fe2+OR‐coupled HER systems in series based on the above Fe2+/Fe3+ cycling, for efficient self‐powered hydrogen evolution. Meanwhile, this Fe2+/Fe3+ cycling enables the preparation of a multifunctional catalyst, Pt‐3@SXNS (siloxene nanosheet), by the Fe2+OR‐promoted dispersion of Pt nanoparticles on SXNS; alternatively, this support could be obtained by Fe3+RR‐assisted exfoliation using Fe3+ from the anolyte of Fe2+OR‐coupled HER. The Pt‐3@SXNS catalyst exhibits excellent catalytic activities toward Fe3+RR in the Zn−Fe flow battery, HER, and Fe2+OR in the electrolyzer, which is attributed to the strong electronic interaction between Pt and Si. This work offers a new strategy for energy storage and low‐cost hydrogen production from acidic wastewater. [ABSTRACT FROM AUTHOR]

Eight-membered cyclic functional bisphosphines, namely 1,5-di-aryl-3,7-di(2-pyridyl)-1,5-diaza-3,7-diphosphacyclooctanes (aryl=2-pyridyl, m-tolyl, p-tolyl, diphenylmethyl, benzyl, ( R)-(+)-(α-methyl)benzyl), with 2-pyridyl substituents on the phosphorus atoms have been synthesized by condensation of 2-pyridylphosphine, formaldehyde, and the corresponding primary amine. The structures of some of these bisphosphines have been investigated by X-ray crystallography. The bisphosphines readily form neutral P,P-chelate complexes [(κ2-P,P-L)MCl2], cationic bis-P,P-chelate complexes [(κ2-P,P-L)2M]2+, or a five-coordinate complex [(κ2-P,P-L)2NiBr]Br. The electrochemical behavior of two of the nickel complexes, and their catalytic activities in electrochemical hydrogen evolution and hydrogen oxidation, including the fuel-cell test, have been studied. [ABSTRACT FROM AUTHOR]

Electrochemical hydrogen production is considered as one of the most significant ways to develop clean energy in the future. Herein, the self‐supporting electrocatalyst of MoS2@Ni(Mn)VOX is fabricated on 3D nickel foam (NF) by a facile two‐step electrodeposition approach. The optimal MoS2@Ni(Mn)VOX electrode shows an ultralow overpotential of 61 mV to achieve a current density of 10 mA cm−2 and a Tafel slope of 35.1 mV dec−1 in 1 m KOH, which is superior to NF, MoS2@NF, NiVOX, Ni(Mn)VOX, or MoS2@NiVOX. The uniformly dispersed coral‐shaped heterostructure exposes more active sites and makes the charge transfer rate faster. The outstanding synergistic effect of MoS2 and transition metal oxides of Ni, Mn, and V also contribute to the enhanced activity of the catalyst. Benefiting from these, MoS2@Ni(Mn)VOX shows superior alkaline hydrogen evolution reaction activity and long‐term stability. Herein, a novel catalyst for highly efficient hydrogen evolution in alkaline media is provided. [ABSTRACT FROM AUTHOR]

The article presents abstracts on topics included in the periodical which include names and information about the editors, mechanism of activation of carbon dioxide and the use of catalysts in the oxidation of hydrogen.

TiO2 with a disc‐like morphology was prepared by direct pyrolysis of a titanium metal–organic framework [MIL‐125(Ti)] in air. Highly dispersed bimetallic AgPd nanoparticles were then anchored on TiO2 and their catalytic performance in the dehydrogenation of formic acid was systematically investigated. The Ag/Pd ratio had a significant effect on the catalyst activity, with Ag2Pd8/TiO2 exhibiting the highest total turnover frequency value of 2579 h−1 at 60 °C under an ambient atmosphere. This excellent performance was attributed to the low‐crystallinity anatase phase structure and large specific surface area of the TiO2 carrier, the alloying effect of the AgPd nanoparticles, and abundant electron transfer between the carrier and metal alloy nanoparticles. [ABSTRACT FROM AUTHOR]

One consistent challenge of both computational and empirical catalyst screening is ensuring that the variables chosen for the screen are driving the performance analyzed. Here, we compare photocatalytic hydrogen evolution from in situ formed Au and Au/Cu nanoparticles to nanoparticles of the same composition synthesized prior to being used as catalysts, as well as compare them to in situ formed Au and Au/Cu nanoparticles in the presence of exogeneous ligand. For all experiments, we observed that ligand‐terminated nanoparticles performed better than un‐stabilized in situ formed nanoparticles. We tested the generality of this result by studying Co, Ni, and Pd in the same system and also observed that the introduction of nanoparticle ligand leads to enhanced catalytic activity. Taken together, these results suggest 1) nanoparticle ligands can be beneficial, and even necessary, to produce catalysts with sustained activity 2) For computational prediction of these catalysts, factors relating to particle formation and stability need to be considered when both generating predictions as well as interpreting experimental results based on those predictions. [ABSTRACT FROM AUTHOR]

The mechanistic uniqueness and versatility of borrowing hydrogen catalysis provides an opportunity to investigate the controllability of a cascade reaction, and more importantly, to realize either one or both of chiral recognition and chiral induction simultaneously. Here we report that, in a borrowing hydrogen cascade starting from racemic allylic alcohols, one of the enantiomers could be kinetically resolved, while the other enantiomer could be purposely converted to various targeted products, including α,β‐unsaturated ketones, β‐functionalized ketones and γ‐functionalized alcohols. By employing a robust Ru‐catalyst, both kinetic resolution and asymmetric induction were achieved with remarkable levels of efficiency and enantioselectivity. Density functional theory (DFT) calculations suggest that corresponding catalyst–substrate π–π interactions are pivotal to realize the observed stereochemical diversity. [ABSTRACT FROM AUTHOR]

The acceptorless dehydrogenation of methanol to carbon monoxide and hydrogen was investigated using homogeneous molecular complexes. Complexes of ruthenium and manganese comprising the MACHO ligand framework showed promising activities for this reaction. The molecular ruthenium complex [RuH(CO)(BH4)(HN(C2H4PPh2)2)] (Ru‐MACHO‐BH) achieved up to 3150 turnovers for carbon monoxide and 9230 turnovers for hydrogen formation at 150 °C reaching pressures up to 12 bar when the decomposition was carried out in a closed vessel. Control experiments affirmed that the metal complex mediates the initial fast dehydrogenation of methanol to formaldehyde and methyl formate followed by subsequent slow decarbonylation. Depending on the catalyst and reaction conditions, the CO/H2 ratio in the gas mixture thus varies over a broad range from almost pure hydrogen to the stoichiometric limit of 1:2. [ABSTRACT FROM AUTHOR]

Using photocatalysis to produce hydrogen is a promising research area in the immediate future. This article intends to design photocatalysts of crystalline (amorphous) TiO2/two‐dimensional MoS2 sandwich structure supporting singleatoms (SAs). After the effective mass, electrostatic potential, light absorption spectrum and other related properties were calculated, the analysis shows that catalysts with amorphous sandwich structure has excellent electron‐hole separation ability, and precious metal SAs can adsord onto the amorphous sandwich structure stably. Except for the Pt@Amorphousr‐TiO2/MoS2 sandwich structure single‐atom catalysts (SACs), which is only active towards oxygen evolution, all the other interlayer catalysts are active for both photocatalytic hydrogen evolution and oxygen evolution. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: The efficient production and utilization of hydrogen play an important role in the closed loop of energy conversion. It is an urgent need to find low‐cost and high‐performance replacements for platinum‐based catalysts towards hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER). Herein, bifunctional RuNi alloy nanoparticles embedded in oxygen‐doped carbon were prepared via simple annealing of Ru‐doped Ni‐BTC, the limiting current density of which could reach 2.46 mA/cm2 (close to Pt) in 0.1 mol/L KOH for HOR. And the low overpotentials of only 29 mV in 1 mol/L KOH and 62 mV in 0.5 mol/L H2SO4 were needed to reach the current density of 10 mA/cm2 for HER. The effect of alloying and oxygen‐doped graphene contributed to the excellent activity and stability during hydrogen electrocatalysis. This work provides new ideas for the development of novel types of hydrogen electrocatalysts and enriches the application of MOFs in HOR. [ABSTRACT FROM AUTHOR]

We have studied the gas phase H2 production by methanol thermo‐photoreforming using Cu‐modified TiO2. Metal co‐catalyst has been deposited by means of photodeposition method. The concentration of methanol in the steam was also considered. It appears that H2 production is notably higher as temperature increases. Moreover, the optimum H2 yield is achieved using methanol concentration of 10 % v/v. CO and CO2 were monitored as side products of the overall reaction. It has been stated that CO evolution is significant at lower temperatures. As temperature increases, CO evolution is hindered and H2 appeared boosted. We have demonstrated that other reactions such water‐gas‐shift or formate dehydration would participate in the overall process. On this basis, optimal operational condition for H2 production is attained for thermo‐photocatalytic reforming of methanol solution 10 % v/v at 200 °C. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: In this work, we screened three Grubbs catalysts and two Hoveyda‐Grubbs catalysts for the production of H2 by dehydrogenation of formic acid (FA). The best results were achieved with the use of a first‐generation Hoveyda‐Grubbs catalyst. With a catalyst loading of mere 0.5 μmol, a maximum TON of 36356 was obtained within 3 h. Two key intermediates were identified by using 1H NMR and high‐resolution electrospray ionization mass spectroscopy (HRESI‐MS), based on which a mechanism possibly responsible for the observed catalysis was proposed. [ABSTRACT FROM AUTHOR]

The instability and expense of anodes for water electrolyzers with acidic electrolytes can be overcome through the implementation of a cobalt‐iron‐lead oxide electrocatalyst, [Co–Fe–Pb]Ox, that is self‐healing in the presence of dissolved metal precursors. However, the latter requirement is pernicious for the membrane and especially the cathode half‐reaction since Pb2+ and Fe3+ precursors poison the state‐of‐the‐art platinum H2 evolving catalyst. To address this, we demonstrate the invariably stable operation of [Co–Fe–Pb]Ox in acidic solutions through a cobalt‐selective self‐healing mechanism without the addition of Pb2+ and Fe3+ and investigate the kinetics of the process. Soft X‐ray absorption spectroscopy reveals that low concentrations of Co2+ in the solution stabilize the catalytically active Co(Fe) sites. The highly promising performance of this system is showcased by steady water electrooxidation at 80±1 °C and 10 mA cm−2, using a flat electrode, at an overpotential of 0.56±0.01 V on a one‐week timescale. [ABSTRACT FROM AUTHOR]

The benchmarking of the performance for H2 evolution of cobalt diimine‐dioxime catalysts is provided based on a comprehensive study of their catalytic mechanism. The latter follows an ECE'CC pathway with intermediate formation of a Co(II)‐hydride intermediate and second protonation possibly at a basic site of the ligand, acting as a proton relay. This suggests an intramolecular coupling between the hydride and protonated ligand as the proton concentration‐independent rate‐determining step controlling the turnover frequency for H2 evolution. [ABSTRACT FROM AUTHOR]

An aldehyde with a cyclohexa‐2,5‐dienyl group in the α‐position is introduced as a storable surrogate of highly reactive acetaldehyde. The cyclohexa‐2,5‐dienyl unit is compatible with an enantioselective Michael addition to nitroalkenes promoted by a Hayashi–Jørgensen catalyst and can be removed by a boron Lewis acid mediated C−C bond cleavage. The robust two‐step sequence does not require a large excess of the aldehyde component that is typically needed when directly using acetaldehyde. [ABSTRACT FROM AUTHOR]

Front Cover: Investigation on the Growth Mechanism of Cu2MoS4 Nanotube, Nanoplate and its use as a Catalyst for Hydrogen Evolution in Water (Chem. Keywords: Inorganic nanotube; metal chalcogenide; mechanism; Kirkendall effect; water splitting EN Inorganic nanotube metal chalcogenide mechanism Kirkendall effect water splitting 1758 1758 1 06/25/20 20200617 NES 200617 B It is about Nanomagics b . Inorganic nanotube, metal chalcogenide, mechanism, Kirkendall effect, water splitting. [Extracted from the article]

A dinuclear copper(II) complex, [CuII2(L)2] is afforded by the reaction of CuCl2·2H2O with a triazenido ligand, 1‐[(2‐carboxymethyl) benzene]‐3‐[2‐carboxybenzene] triazene (H2L). Structural investigation shows that the copper‐copper distance [2.3985(7) Å] is significantly shorter than the sum of the van der Waals radii of Cu (1.40 Å), suggesting that there are metal‐metal bonds in [CuII2(L)2]. In solid, there is a strong antiferromagnetic interaction between copper(II) ions (J = –135.6 cm–1). In homogeneous environment, [CuII2(L)2] shows electrocatalytic activities for hydrogen generation both from acetic acid with a turnover frequency (TOF) of 32 mol of hydrogen per mole of catalyst per hour [mol(H2)·mol–1(catalyst)·h–1] at an overpotential (OP) of 941.6 mV, and neutral buffer with a TOF of 512 mol(H2)·mol–1(catalyst)·h–1 at an OP of 836.7 mV. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of CO2 is an attractive strategy towards the mitigation of environmental pollution and production of bulk chemicals as well as fuels by renewables. The bimetallic sulfide Fe4.5Ni4.5S8 (pentlandite) was recently reported as a cheap and robust catalyst for electrochemical water splitting, as well as for CO2 reduction with a solvent‐dependent product selectivity. Inspired by numerous reports on monometallic sulfoselenides and selenides revealing higher catalytic activity for the CO2 reduction reaction (CO2RR) than their sulfide counterparts, the authors investigated the influence of stepwise S/Se exchange in seleno‐pentlandites Fe4.5Ni4.5S8‐YSeY (Y=1–5) and their ability to act as CO2 reducing catalysts. It is demonstrated that the incorporation of higher equivalents of selenium favors the CO2RR with Fe4.5Ni4.5S4Se4 revealing the highest activity for CO formation. Under galvanostatic conditions in acetonitrile, Fe4.5Ni4.5S4Se4 generates CO with a Faradaic Efficiency close to 100 % at applied current densities of −50 mA cm−2 and −100 mA cm−2. This work offers insight into the tunability of the pentlandite based electrocatalysts for the CO2 reduction reaction. [ABSTRACT FROM AUTHOR]

Fischer‐Tropsch synthesis of the CO2 in biogas aims at producing light hydrocarbons and increasing its calorific value for feeding into the grid. Fe catalysts with Mn and K as promoters are supposed to yield high amounts of light hydrocarbons. Using a Fe‐Mn‐K/MgO catalyst, a parameter screening and long‐term experiments were carried out. The catalyst shows, within the examined range, the highest selectivity to C2–C4 hydrocarbons at 450 °C, 8 bar(a), and a gas hourly space velocity of 350 h−1. Calcination of the catalyst resulted in a significant drop of activity and an almost complete loss of selectivity to hydrocarbons. Admixture of steam to the reactant gas lowers the tendency to carbon deposition but also promotes the water‐gas shift reaction and results in lower yields of hydrocarbons. [ABSTRACT FROM AUTHOR]

Here we describe a new conceptual approach for the design of a heterogeneous metal‐organic framework (MOF) catalyst based on UiO‐67 for the selective decarboxylation of formic acid, a reaction with important applications in hydrogen storage and in situ generation of H2. Models for the {CuH} reactive catalytic site at the organic linker are assessed. In the first model system, gas‐phase mass spectrometry experiments and DFT calculations on a fixed charge bathophen ligated copper hydride complex, [(phen*)Cu(H)]2−, were used to demonstrate that it acts as a catalyst for the selective decomposition of formic acid into H2 and CO2 via a two‐step catalytic cycle. In the first step liberation of H2 to form the carboxylate complex, [(phen*)Cu(O2CH)]2− occurs, which in the second step selectively decomposes via CO2 extrusion to regenerate the hydride complex. DFT calculations on four other model systems showed that changing the catalyst to neutral [(LCu(H)] complexes or embedding it within a MOF results in mechanisms which are essentially identical. Thus catalytic active sites located on the organic linker of a MOF appear to be close to a gas‐phase environment, thereby benefitting from the favorable characteristics of gas‐phase reactions and validating the use of gas‐phase models to design new MOF based catalysts. [ABSTRACT FROM AUTHOR]

Abstract: High impact polypropylene (hiPP) powders are made in a 2.5 L semi‐batch gas‐phase reactor using a Ziegler–Natta catalyst and two sequential polymerization steps. The amount of copolymer, reactor temperature and pressure, the relative amounts of ethylene and propylene, and the presence of hydrogen are varied systematically to understand their impact on the copolymerization kinetics, hiPP properties, and on rubber distribution. Examples of discoveries are that the presence of hydrogen can reduce copolymerization activity, depending on the catalyst system, and that the fraction of crystalline copolymer decreases with 1) copolymer content in hiPP; and 2) copolymerization activity. The last implies a resistance to mass transfer of ethylene during copolymerization. To understand this phenomenon, atomic force microscopy analyses of hiPP samples with distinct morphology of the polypropylene matrix (isotactic polypropylene, iPP) and copolymer ethylene/propylene ratios are performed after microtoming. It is found that mesoparticles are the determining structure for the copolymer distribution, and that powders with more ethylene in the copolymer or an iPP matrix better suited for mass transfer had more rubber in the center of the mesoparticles. This indicates that the length scales of the mesoparticles that control transfer limitations for ethylene also impact the properties of the final impact copolymer. [ABSTRACT FROM AUTHOR]

Invited for this month′s cover is the group of Prof. Fokko M. Mulder at the Delft University of Technology. The image on the cover shows how in the NH3 synthesis via hydrogen‐permeable electrode the N, H species on the catalyst surface can be controlled, using the analogy of a traffic controller. The Research Article itself is available at 10.1002/cssc.202300460. [ABSTRACT FROM AUTHOR]

A series of [OsII(NN)(CO)2Cl2] complexes where NN is a 2,2′-bipyridine ligand substituted in the 4,4′ positions by H ( C1), CH3 ( C2), C(CH3)3 ( C3), or C(O)OCH(CH3)2 ( C4) has been studied as catalysts for the reduction of CO2. Electrocatalysis shows that the selectivity of the reaction can be switched toward the production of CO or HCOO− with an electron-donating ( C2, C3) or -withdrawing ( C4) substituent, respectively. The electrocatalytic process is a result of the formation of an Os0-bonded polymer, which was characterized by electrochemistry, UV/Visible and EPR spectroscopies. Photolysis of the complexes under CO2 in DMF+TEOA produces CO as a major product with a remarkably stable turnover frequency during 14 h of irradiation. Our results suggest that electrocatalysis and photocatalysis occur through two distinct processes, starting mainly from an OsI dimer precatalyst if the reduction is performed by an electrode and an OsI mononuclear species in case of a photoreduction process. [ABSTRACT FROM AUTHOR]

A general concept for the covalent linkage of coordination compounds to bipyridine-functionalized polyoxometalates is presented. The new route is used to link an iridium photosensitizer to an Anderson-type hydrogen-evolution catalyst. This covalent dyad catalyzes the visible-light-driven hydrogen evolution reaction (HER) and shows superior HER activity compared with the non-covalent reference. Hydrogen evolution is observed over periods >1 week. Spectroscopic, photophysical, and electrochemical analyses give initial insight into the stability, electronic structure, and reactivity of the dyad. The results demonstrate that the proposed linkage concept allows synergistic covalent interactions between functional coordination compounds and reactive molecular metal oxides. [ABSTRACT FROM AUTHOR]

Development of catalysts with high activity and durability is essential for the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) of water splitting. Three-dimensional catalysts have large surface areas and good mechanical and antipoisoning properties and can directly act as working electrodes; these are especially important factors from the point of view of practical applications. Here we review recent significant progress in the field of three-dimensional catalysts for water splitting. Various three-dimensional catalysts that can be applied in electrocatalytic water splitting are presented. The fabricating methods, electrocatalytic performances, and the catalytic mechanisms of these catalysts are introduced. Lastly, the major challenges in this particular field and their prospective solutions are also discussed. [ABSTRACT FROM AUTHOR]

For hydrogen production, by steam reforming, porous ceramics are broadly used as catalyst support, due to their stability and ease in shaping. Catalyst supports in the form of tablets are conventionally produced by powder pressing and subsequent sintering. However, if the process is not done properly, cracks may arise and propagate during the sintering of the tablets. This can lead to weak sintered tablets that get rejected in the quality control. For this work, crack-containing samples of rejected tabletized support were provided. The formation, growth and closure of internal cracks during sintering of the rejected tabletized support material are studied by 3D X-ray tomography. This is a powerful technique, which due to its nondestructive nature is suitable to study the development of internal cracks in the tablets during sintering. Cracks could be identified in the green tablet (before sintering), which may indicate an uneven compaction of the powder, leading to an uneven spring-back after compaction. During sintering, some of the initial cracks were observed to close, while others were observed to open. Furthermore new cracks were also observed to arise during sintering. The different cracks locations and developments were analyzed in relationship to the surrounding microstructural features in an attempt to understand the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Electrocatalytic hydrogen evolution has been regarded as a promising strategy to realize efficient hydrogen production to face the energy crisis in the future. Hence, the design of hydrogen-evolving catalysts with high activity and low cost is imperative. In this Minireview article, state-of-the-art electrocatalysts for the hydrogen evolution reaction (HER) are overviewed, and the strategies for constructing ordered and disordered HER electrocatalysts are summarized in detail. By means of facet engineering, nanoscale, polymorph engineering accompanied by interface engineering, HER catalysts with an ordered structure could be optimized. For designing disordered catalysts, defect engineering, amorphization, elemental doping, and surface modification, as well as constructingan alloyed structure, could be effective to realize the beneficial modulation of active sites and electronic structure. This Minireview provides a structural perspective for the design of efficient HER electrocatalysts in the future. [ABSTRACT FROM AUTHOR]

Highly dispersed PdCu alloy nanoparticles have been successfully prepared within a macroreticular basic resin bearing N(CH3)2 functional groups. This previously unappreciated combination of alloy is first proven to be responsible for the efficient production of high-purity H2 from formic acid (HCOOH) dehydrogenation for chemical hydrogen storage. By the addition of Cu, the electronically promoted Pd sites show significantly higher catalytic activity as well as a better tolerance towards CO poisoning as compared to their monometallic Pd counterparts. Experimental and DFT calculation studies revealed not only the synergic alloying effect but also cooperative action by the N(CH3)2 groups within the resin play crucial roles in achieving exceptional catalytic performances. In addition to the advantages such as, facile preparation method, free of additives, recyclable without leaching of active component, and suppression of unfavorable CO formation less than 3 ppm, the present catalytic system is cost-effective because of the superior catalytic activity compared with that of well-established precious PdAg or PdAu catalysts. The present catalytic system is particularly desirable for an ideal hydrogen vector in terms of potential industrial application for fuel cells. [ABSTRACT FROM AUTHOR]

A highly effective and operationally simple method for the deuteration of phenols using NaOH as a catalyst and D2O as the deuterium source is presented. A high regioselectivity for the ortho and/or para hydrogens relative to the oxygen atom was achieved, as well as a high degree of deuterium incorporation. The method also has a high functional-group tolerance, and allowed the deuteration of complex pharmaceutically interesting substrates. [ABSTRACT FROM AUTHOR]

Hydrogen production through the use of renewable raw materials and renewable energy is crucial for advancing its applications as an energy carrier. In this study, we fabricated a solid oxide solution of Cu and Ni within a confined pore space, followed by a partial reduction, to produce a highly efficient catalyst for ethanol steam reforming (ESR). At 300 °C, EtOH is completely converted, a H2 yield of approximately 5 mol per mol is achieved, and CO2 is the main carbon-containing product. This demonstrates that H2 production from bioethanol is an efficient and sustainable approach. Such a highly efficient ESR catalyst is attributed to the ability of the metal-oxide interface to facilitate the transformation of CH x adspecies from acetaldehyde decomposition into methoxy-like adspecies, which are reformed readily to produce H2 and consequently reduce CH4 formation. [ABSTRACT FROM AUTHOR]

Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]-hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale-up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its β-FeOOH NA/Ti precursor through a low-temperature phosphidation reaction. When applied as self-supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm2, respectively. The excellent electrocatalytic performance is promising for applications as non-noble-metal HER catalyst with a high performance-price ratio in electrochemical water splitting for large-scale hydrogen fuel production. [ABSTRACT FROM AUTHOR]