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The design of diatomic catalysts with uniformly dispersed metal atoms is expected to improve catalytic performance, which is conducive to the intensive comprehending of the synergistic mechanism between dual-metal sites for the oxygen evolution reaction (OER) at the atomic level. Herein, we design a strategy to immobilize bimetallic Fe-Co atoms onto nitrogen-doped graphene to obtain a diatomic catalyst (DA-FC-NG) with FeN3-CoN3 configuration. The DA-FC-NG shows excellent OER activity with a low overpotential (η10 = 268 mV), which is superior to commercial iridium dioxide catalysts. Theoretical calculations uncover that the excellent activity of DA-FC-NG is due to the interaction between Fe and Co diatoms, which causes charge rearrangement and induces the adsorption of intermediates on the Fe–O–Co bridge structure, thus improving the catalytic OER performance. This work is of great significance for the design of highly active diatomic catalysts to replace noble metal catalysts for energy-related applications. [ABSTRACT FROM AUTHOR]

Copper is the only metal that can convert CO2 into C2 and C2+ in electrocatalytic carbon dioxide reduction (CO2RR). However, the Faraday efficiency of CO2 conversion to C2 and C2+ products at high current densities is still low, which cannot meet the actual industrial demand. Here, the design methods of single‐atom copper catalysts (including regulating the coordination environment of single‐atom copper, modifying the carbon base surface and constructing diatomic Cu catalysts) are reviewed, and the current limitations and future research directions of copper‐based single‐atom catalysts are proposed, providing directions for the industrial conversion of CO2 into C2 and C2+ products. [ABSTRACT FROM AUTHOR]

Electrochemical carbon dioxide reduction reaction (CO2RR) is an efficient strategy to relieve global environmental and energy issues by converting excess CO2 from the atmosphere to value‐added products. Atomically dispersed metal‐nitrogen‐doped carbon (M‐N‐C) materials are superior catalysts for electrocatalytic CO2RR because of the 100% atomic utilization, unsaturated coordination configuration, relatively uniform active sites, and well‐defined and adjustable structure of active centers. However, the electrochemical CO2RR is a great challenge due to the process involving proton‐coupled multi‐electron transfer with a high energy barrier, which leads to unsatisfactory selectivity to the targeted product, especially for C2 products (e.g., C2H4 and C2H5OH). Here, the authors systematically summarize effective means, including reasonable selection of isolated metal sites, regulation of the coordination environment of isolated metal atoms, and fabrication of dimetallic single‐atom sites for attaining optimal geometric and electronic structures of M‐N‐C materials and further correlate these structures with catalytic selectivity to various C1 (e.g., CO and CH4) and C2 products in the CO2RR. Moreover, constructive strategies to further optimize M‐N‐C materials for electrocatalytic CO2RR are provided. Finally, the challenges and future research directions of the application of M‐N‐C materials for electrocatalytic CO2RR are proposed. [ABSTRACT FROM AUTHOR]

In this work, we synthesized a series of 20% Ni-x% Cu/Al2O3 catalysts containing various Cu loading by the impregnation method and investigated their catalytic performance in the amination of diethylene glycol (DEG) with tertiarybutylamine (TBA) to tertiarybutylaminoethoxyethanol (TBEE). A variety of characterization techniques including XRD, TEM, BET, XPS, H2-TPR, NH3-TPD, CO2-TPD were applied. The promotional influence of Cu on the catalytic performance of Ni/Al2O3 catalyst was studied, and the optimal addition of Cu was obtained. Indeed, we found that Ni–Cu alloy was formed after reduction of the Ni–Cu/Al2O3 catalysts. Due to the strong interaction between Cu and Ni, Cu could improve the reducibility of NiO and the dispersion of Ni species on the catalyst surface, which were critical factors for higher reactivity of the bimetallic Ni–Cu/Al2O3 catalysts. Moreover, the influence of catalyst reduction temperature and reaction temperature were examined. When operating at 230 °C, the 20% Ni-10% Cu/Al2O3 catalyst reduced at 500 °C for 2 h exhibited superior catalytic performance in this reaction. Ni-Cu/Al2O3 catalyst was found to be an effective catalyst for catalytic amination of diethylene glycol with tertiarybutylamine. [ABSTRACT FROM AUTHOR]

The Cu/ZnO/Al2O3 catalysts prepared by co-precipitation method were used for the hydrogenation of methyl benzoate to benzyl alcohol. These catalysts were characterized at various stages of preparation by nitrogen adsorption-desorption, X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The experimental results show that the addition of ZnO to the catalyst greatly improves the selectivity of benzyl alcohol. When the Cu/Zn/Al molar ratio is 2:2:1 and the calcination temperature of the catalyst is 650 °C, the catalyst exhibits very highly catalytic performance. In addition, the effects of reaction temperature, pressure and time were also investigated during the hydrogenation of methyl benzoate to benzyl alcohol. When the methyl benzoate was hydrogenated over this catalyst at 160 °C and 7 MPa of H2 for 10 h, the conversion of methyl benzoate can reach 93.89% and the selectivity of benzyl alcohol is 88%. This effectively catalytic performance can be attributed to the presence of highly dispersed and stable metallic copper nanoparticles, and the weak acidity of the catalyst surface. Besides, the reaction pressure and temperature play a crucial role in the conversion of methyl benzoate and the selectivity of benzyl alcohol.Graphical Abstract: Application of Cu/ZnO/Al2O3 catalyst in hydrogenation of methyl benzoate to benzyl alcohol. [ABSTRACT FROM AUTHOR]

Abstract: For the dehydrogenation of cyclohexanol a series of Cu–ZnO/SiO2 catalysts with various Cu to ZnO molar ratios was prepared using the impregnation method, with the loading of copper fixed at 9.5at.%. The catalysts were characterized by XPS, H2–N2O titration, BET, H2-TPR, NH3-TPD and XRD techniques. The results indicate that the addition of ZnO can improve the dispersion of copper species on reduced Cu–ZnO/SiO2 (CZS) catalysts. Cu0 and Cu+ species were found on the reduced CZS catalysts surface, and the amount of Cu+ increased with the content of ZnO increasing. The addition of ZnO increased the acidity of the CZS catalysts. However, only Cu0 species can be found on the reduced Cu/SiO2 (CS) catalyst surface. According to the reaction results, we found that the selectivity to phenol was related to the amount of Cu+ species, the Cu+ species should be the active sites for the production of phenol, the Cu0 is responsible for cyclohexanol dehydrogenation to cyclohexanone. [Copyright &y& Elsevier]