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Metal carbides with earth-abundant elements are widely regarded as promising alternatives to noble metal catalysts. Although comparable catalytic performances have been observed for metal carbides in several types of reactions, precise control of reaction pathways on them remains a formidable challenge, partially due to strong adsorption of reactants or intermediates. In this study, we show that bimolecular dehydrogenation of methanol to methyl formate and H 2 is kinetically favored on bare α-MoC catalysts, while monomolecular dehydrogenation to CO and H 2 becomes the dominant pathway when α-MoC is decorated with crowding atomic Ni species. Under optimal conditions, excellent selectivities of the target products (>90 %) were achieved in both cases, with unprecedented production rates of methyl formate and H 2 for the former and latter mechanisms, respectively. Kinetic, spectroscopic, and computational assessments were integrated to clarify the mechanism driving this remarkable selectivity inversion. Isolated Ni sites bound to α-MoC exhibit superior dehydrogenation activity, which promotes complete cleavage of C-H bonds in methanol-derived intermediates rather than the C-O coupling between them. Our study offers an effective approach to modulating the selectivity of carbide-based catalysts in alcohol dehydrogenation towards different target products., (© 2024 Wiley-VCH GmbH.)

Molybdenum carbide has been reported as an efficient and stable catalyst for reverse water-gas shift reaction. The convention understanding of the mechanism suggests domination of the surface phenomena, with only surface or subsurface layers partaking in the catalytic cycle. In this study, we presented a highly active MoC catalyst from carburization process, which showed a mass-specific reaction rate over 260 [[EQUATION]] with dynamic carbon flux in the bulk phase of the catalyst. Through Isotopic Temperature-Programmed Reaction (ITPR) analysis and Environmental Transmission Electron Microscopy (ETEM), we discerned dynamic carbon flow circulating between the α-MoC bulk phase and the gas phase reactants under the reverse water-gas shift (RWGS) reaction atmosphere. This circulation, essential to maintaining the structural stability of the metastable α-MoC and its ultra-high reactivity, is accompanied by thorough carbon component exchange among the bulk, the surface and the gas-phase reactants during the reaction process., (© 2024 Wiley‐VCH GmbH.)

As a well-established topic, single-atom catalyst has drawn growing interest for its high utilization of metal. However, researchers prefer to develop various active metals with single-atom form, the intrinsic roles of single-atom promoters are usually underrated, which are significant in boosting reaction activity. In this work, Ba single atoms were in situ prepared in the Co-Ba/Y 2 O 3 catalyst with crystallized BaCO 3 as the precursor under the ammonia decomposition reaction condition. The optimized Co-Ba/Y 2 O 3 catalyst achieves extremely high H 2 production rate of 138.3 mmolH 2  ⋅ g cat -1  ⋅ min -1 at very low temperature (500 °C, GHSV=840,000 mL ⋅ g -1  ⋅ h -1 ) and Co-Ba/Y 2 O 3 exhibits excellent durability during the 350 h test, which realizes the highest activity among all non-noble catalysts, and reaches or even exceeds numerous reported Ru-based catalysts. Both Y 2 O 3 and Co demonstrate positive interactions with Ba, which significantly facilitates the dispersion of Ba species at high temperatures (≥600 °C). Ba single atoms significantly enhance the charge density of Co and form additionally active Co-O-Ba-Y 2 O 3 interfacial sites, which alleviates hydrogen poisoning and decreases the reaction barrier of the N-H bond activation of *NH. The exploration of atomically dispersed promoters is groundbreaking in heterogeneous catalysis, which opens up a whole new domain of catalytic material., (© 2024 Wiley-VCH GmbH.)

The C-C coupling of methane (CH 4 ) and carbon dioxide (CO 2 ) to generate acetic acid (CH 3 COOH) represents a highly atom-efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH 4 and CO 2 present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (⋅OH) and hydrated electrons (e aq - ) produced by water radiolysis can effectively activate CH 4 and CO 2 , yielding methyl radicals (⋅CH 3 ) and carbon dioxide radical anions(⋅CO 2 - ) that facilitate the production of CH 3 COOH at ambient temperature. The introduction of radiation-synthesized CuO-anchored TiO 2 bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol ⋅ L -1 of CH 3 COOH with near-unity selectivity (>95 %). These findings offer valuable insights for catalyst design and implementation in radiation-induced chemical conversion., (© 2024 Wiley-VCH GmbH.)

Liquid organic hydrogen carriers (LOHCs) are attractive platform molecules that play an important role in hydrogen energy storage and utilization. The multi-step hydrogenation of toluene (TOL) to methylcyclohexane (MCH) has been widely studied in the LOCHs systems, due to their relatively low toxicity and reasonable hydrogen storage capacity. Noble metal catalysts such as Ru has exhibited good performance in multi-step hydrogenation reactions, while the application is still hindered by their high cost and low specific activity. Therefore, the primary challenge lies in the development of noble metal catalysts with both robust activity and efficient atomic utilization. In this study, a series of Ru species ranging from single atoms, fully exposed clusters to nanoparticles were fabricated to investigate their structural evolution in the TOL multi-step hydrogenation reaction. The fully exposed and atomically dispersed Ru clusters, composed of an average of 3 Ru atoms, exhibit superior catalytic performance and recycle ability in TOL multi-step hydrogenation. Moreover, it delivers a high turnover frequency of 9850.3 h -1 under the relatively mild reaction (100 °C, 1.5 MPa), compared with those of single atoms and nanoparticles, and shows a notable advantage over catalysts reported in previous studies. From density functional theory (DFT) calculations, the overall barrier of the TOL multi-step hydrogenation reaction over the fully exposed Ru clusters is significantly lower than that of single atoms and nanoparticles, resulting in its higher activity. The present work provides an efficient strategy to regulate the reaction pathway of multi-step complicated catalytic reactions by designing fully exposed metal cluster catalysts., (© 2024 Wiley-VCH GmbH.)

Electrocatalytic oxidation of C-H bonds in hydrocarbons represents an efficient and sustainable strategy for the synthesis of value-added chemicals. Herein, a highly selective and continuous-flow electrochemical oxidation process of toluene to various oxygenated products (benzyl alcohol, benzaldehyde, and benzyl acetate) is developed with the electrocatalytic membrane electrodes (ECMEs). The selectivity of target products can be manipulated via surface and interface engineering of Co 3 O 4 -based electrocatalysts. We achieved a high benzaldehyde selectivity of 90 % at a toluene conversion of 47.6 % using 1D Co 3 O 4 nanoneedles (NNs) loaded on a microfiltration (MF) titanium (Ti) membrane, i.e, Co 3 O 4 NNs/Ti. In contrast, the main product shifted to benzyl alcohol with a selectivity of 90.1 % at a conversion of 32.1 % after modifying MnO 2 nanosheets (NSs) on Co 3 O 4 NNs/Ti (Co 3 O 4 @MnO 2 /Ti) catalyst. Moreover, benzyl acetate product can be obtained with a selectivity of 92 % at a conversion of 58.5 % at high current density (>1.5 mA cm -2 ), demonstrating that the pathway of toluene oxidation is readily maneuvered. DFT results reveal that modifying MnO 2 on Co 3 O 4 optimizes the electron structure of Co 3 O 4 @MnO 2 /Ti and modulates the adsorption behavior of intermediate species. This work demonstrates a sustainable, efficient, and continuous-flow process for precise control over the production selectivity of value-added oxygenated derivatives in the electrochemical oxidation of aromatic hydrocarbons., (© 2024 Wiley-VCH GmbH.)

Direct conversion of methane into value-added chemicals, such as methanol under mild conditions, is a promising route for industrial applications. In this work, atomically dispersed Rh on TiO 2 suspended in an aqueous solution was used for the oxidation of methane to methanol. Promoted by copper cations (as co-catalyst) in solution, the catalysts exhibited high activity and selectivity for the production of methanol using molecular oxygen with the presence of carbon monoxide at 150 °C with a reaction pressure of 31 bar. Millimole level yields of methanol were reached with the selectivity higher than 99 % using the Rh/TiO 2 catalysts with the promotion of the copper cation. CO was the reductive agent to generate H 2 from H 2 O, which led to the formation of H 2 O 2 through the reaction of H 2 and O 2 . Atomically dispersed Rh activated the C-H bond in CH 4 and catalyzed the oxidation using H 2 O 2 . Copper cations maintained the low-valence state of Rh. Moreover, copper acted as a scavenger for suppressing the overoxidation, thus leading to the high selectivity of methanol., (© 2022 Wiley-VCH GmbH.)

Catalytic combustion is promising in removing trace amounts of CH 4 to address serious environmental concerns. Supported Pd-based catalysts are most effective but often suffer from low stability in applications owing to the water-vapor-induced sintering. Herein, we develop a universal strategy to prepare irreducible-oxide-modified Pd/MgAl 2 O 4 catalysts which show high activity and excellent stability against both hydrothemal aging at elevated temperatures and deactivation in long-term reaction under wet conditions. The addition of irreducible oxides inhibited the deep oxidation of Pd in the oxygen-rich conditions, which preserved not only the epitaxial structure but also a suitable active phase of Pd-PdO x on MgAl 2 O 4 , thus promoting both activity and stability. This work provides new insights into the effect of metal-oxide interaction on CH 4 combustion and offers an avenue to design hydrothermally stable and active combustion catalysts for industrial applications., (© 2020 Wiley-VCH GmbH.)

The development of highly efficient metal-free carbon electrocatalysts for the oxygen reduction reaction (ORR) is one very promising strategy for the exploitation and commercialization of renewable and clean energy, but this still remains a significant challenge. Herein, we demonstrate a facile approach to prepare three-dimensional (3D) N-doped carbon with a sp 3 /sp 2 carbon interface derived from ionic liquids via a simple pyrolysis process. The tunable hybrid sp 3 and sp 2 carbon composition and pore structures stem from the transformation of ionic liquids to polymerized organics and introduction of a Co metal salt. Through tuning both composition and pores, the 3D N-doped nanocarbon with a high sp 3 /sp 2 carbon ratio on the surface exhibits a superior electrocatalytic performance for the ORR compared to that of the commercial Pt/C in Zn-air batteries. Density functional theory calculations suggest that the improved ORR performance can be ascribed to the existence of N dopants at the sp 3 /sp 2 carbon interface, which can lower the theoretical overpotential of the ORR., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)