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Catalytic conversion of CO2 to produce fuels and chemicals is of great importance, and the electrocatalytic CO2 reduction reaction (eCO2RR) is considered one of the most attractive pathways. Multi-carbon (C2+) products are more desirable in many cases. To date, Cu-based catalysts, especially Cu+ sites, have been found to be the most efficient for the production of C2+ products. However, the retention of Cu+ sites at high cathodic potentials in the eCO2RR remains a great challenge. In this study, we designed and synthesized CuAl-oxide-derived (CuxAly-OD, x and y are the mass percentages of Cu and Al) catalysts for the eCO2RR to C2+ products. During the eCO2RR process, the predominant Cu species changed to Cu+, and the resulting electrocatalyst showed a high faradaic efficiency (FE) of 81.6% for C2+ products in alkaline aqueous solutions. Experimental studies showed that the presence of a stable amorphous Al2O3 phase stabilized the Cu+ sites by oxidation state control, leading to high selectivity and activity for the production of C2+ products. This work provides a strategy for improving the stability of Cu+ in the catalyst to enhance the performance of the eCO2RR. [ABSTRACT FROM AUTHOR]

Electrochemical reduction of CO2 by renewable electricity offers a promising way to settle excessive greenhouse gases and achieve carbon neutrality under a mild environment. Cu-based catalysts have a unique catalytic activity towards multicarbon (C2+) products in the CO2 electroreduction reaction and are widely studied to promote the corresponding selectivity and activity. Here we report a F-doped Cu (F–Cu) catalyst to improve C2+ products in CO2 electroreduction. A high C2+ product (mainly ethylene and ethanol) faradaic efficiency of 70.4% was achieved on the F–Cu catalyst with a high current density (above 400 mA cm−2) in the flow-cell system. The in situ surface enhanced Raman spectroscopy results and electrochemical performance analysis demonstrated that CO2 could be reduced into CO at low potentials and the adsorption of CO could be strengthened on F–Cu, which is beneficial to the subsequent C–C coupling step and formation of the C2+ products. [ABSTRACT FROM AUTHOR]

Sn4P3/reduced graphene oxide nanocomposites exhibited high selectivity for CO over a wide potential range from −2.2 V to −2.5 V vs. Ag/Ag+. The maximum faradaic efficiency for CO can reach 96.6% with a high current density of 68.0 mA cm−2. The high efficiency and selectivity can be attributed to the modified electronic structure of Sn sites, the small Sn4P3 nanoparticles and their dense packing in a conductive matrix, leading to a high density of active sites for adsorbing CO2 and stabilizing the CO2˙− intermediate. [ABSTRACT FROM AUTHOR]

Cuprous oxide catalysts have attracted much attention because they exhibited high selectivity of C2+ products in CO2 electroreduction, but the effect of the structure of catalysts on the reaction needs to be studied further. Herein, we studied the effect of the coordination number (CN) of Cu–Cu and Cu–O in Cu2O on the catalytic performance of CO2 electrocatalytic reduction to C2H4. It was demonstrated that Cu–Cu CN and Cu–O CN, which could be tuned by changing the crystal surface and size of Cu2O, influenced the current density and faradaic efficiency (FE) of C2H4 significantly. At suitable CNs, the FE of C2H4 could reach 50.6% with a current density of 24.5 mA cm−2. [ABSTRACT FROM AUTHOR]

Cu(OH)2/CuO nanocomposite-derived Cu2O/Cu was highly efficient for CO2 electroreduction to C2 products. The highest faradaic efficiency and current density could reach 64.5% and 26.2 mA cm−2, respectively. By changing the calcination time, moderate grain boundary density and the Cu+/Cu0 ratio in catalysts can be controlled, leading to a large number of active sites and low interfacial charge transfer resistance. [ABSTRACT FROM AUTHOR]

Bi2WO6 nanosheets with plentiful oxygen vacancies were synthesised, and were highly efficient for the electroredution of CO2 to CO. The faradaic efficiency of CO could reach 91% with a high current density of 43 mA cm−2 at low potentials. The oxygen vacancies could enhance the reaction effectively by improving the adsorption and activation of CO2. [ABSTRACT FROM AUTHOR]

MOF-derived In–Cu bimetallic oxides are highly efficient electrocatalysts for the transformation of CO2 into CO in an aqueous electrolyte. By controlling In/Cu ratios, the faradaic efficiency of CO could reach 92.1%. The excellent performance is mainly attributed to stronger CO2 adsorption, higher electrochemical surface area and lower charge transfer resistance. [ABSTRACT FROM AUTHOR]

B-Doped oxide-derived-Cu is a highly efficient electrocatalyst for transformation of CO2 to C2 products. The faradaic efficiency of C2 products could reach 48.2%, with a high current density of 33.4 mA cm−2 at low potentials in 0.1 M KHCO3 electrolyte. The excellent performance of the catalyst is mainly attributed to Cu+ species stabilized by the introduction of B. [ABSTRACT FROM AUTHOR]

We developed a route to prepare nanoporous Cu/Ni oxide composites. It was discovered that the Cu/Ni oxide composites were very efficient electrocatalysts for CO2 reduction to formate in aqueous electrolytes. The excellent performance resulted mainly from the porous structure, synergistic effect of the two oxides, and low charge transfer resistance. [ABSTRACT FROM AUTHOR]

Ethanol is an important bulk chemical and alternative fuel that is currently synthesized by catalytic hydration of ethylene or fermentation of foods. CO2 is a cheap and renewable carbon resource. Transformation of CO2 into useful chemicals is an interesting topic in green chemistry. Production of ethanol using CO2 and H2 is a promising route, but the efficiency of the reaction is not satisfactory. In this paper, we propose a protocol to synthesize ethanol from paraformaldehyde, CO2 and H2. The reaction could be efficiently accelerated by a Ru–Co bimetallic catalyst using LiI as the promoter in 1,3-dimethyl-2-imidazolidinone (DMI) under mild conditions. The selectivity of ethanol in total products reached 50.9 C-mol%, which was obviously higher than that of the reported routes. Furthermore, the TOF of ethanol based on Ru metal was as high as 17.9 h−1. To our knowledge, this is the first report on ethanol synthesis from paraformaldehyde, CO2 and H2. A detailed study indicated that the outstanding results of the reaction originated from the synergy of paraformaldehyde hydrogenation, reverse water gas shift reaction and methanol homologation. [ABSTRACT FROM AUTHOR]

Acetic acid is an important bulk chemical and synthesis of acetic acid via methanol hydrocarboxylation with CO2 and H2 is a very promising route. In this work, we studied the reaction over a number of catalytic systems. It was found that Rh2(CO)4Cl2 with 4-methylimidazole (4-MI) as the ligand was very efficient in the presence of LiCl and LiI. Acetic acid began to form at 150 °C. The TOF was as high as 26.2 h−1 and the yield of acetic acid could reach 81.8% at 180 °C. The catalytic system had obvious advantages, such as simplicity, high activity and selectivity, milder reaction conditions, and less corrosiveness. The excellent cooperation of CO and Cl− in Rh2(CO)4Cl2, suitable basicity and aromaticity of the ligand 4-MI, and the hydrogen bonding ability of Cl− were crucial for the outstanding performance of the catalytic system. The control experiments showed that the reaction did not proceed via the CO pathway. [ABSTRACT FROM AUTHOR]

The highly selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA-oil) under benign and green conditions is still a challenging topic. In this work, V2O5@TiO2 catalysts were prepared by V species deposited on TiO2 (P25) and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and UV-vis diffuse reflectance techniques. The selective aerobic oxidation of cyclohexane was carried out over V2O5@TiO2 catalysts with oxygen as an oxidant under simulated light irradiation. The influences of solvents, metals and mass of V species deposited on TiO2, pressure of oxygen, and reaction time on the reaction were investigated. It was found that the V species deposited on the TiO2 surface was very efficient for the photocatalytic oxidation of cyclohexane under simulated solar light irradiation. More interestingly, the selectivity of the reaction in an acetonitrile/water mixed solvent was much higher than that in other solvents. Under the optimized conditions, the selectivity to KA-oil products could be nearly 100% at a cyclohexane conversion of 18.9%. The possible pathway for the catalytic reaction was proposed. [ABSTRACT FROM AUTHOR]

MOF-derived In–Cu bimetallic oxides are highly efficient electrocatalysts for the transformation of CO2 into CO in an aqueous electrolyte. By controlling In/Cu ratios, the faradaic efficiency of CO could reach 92.1%. The excellent performance is mainly attributed to stronger CO2 adsorption, higher electrochemical surface area and lower charge transfer resistance. [ABSTRACT FROM AUTHOR]

Ethanol is an important bulk chemical and alternative fuel that is currently synthesized by catalytic hydration of ethylene or fermentation of foods. CO2 is a cheap and renewable carbon resource. Transformation of CO2 into useful chemicals is an interesting topic in green chemistry. Production of ethanol using CO2 and H2 is a promising route, but the efficiency of the reaction is not satisfactory. In this paper, we propose a protocol to synthesize ethanol from paraformaldehyde, CO2 and H2. The reaction could be efficiently accelerated by a Ru–Co bimetallic catalyst using LiI as the promoter in 1,3-dimethyl-2-imidazolidinone (DMI) under mild conditions. The selectivity of ethanol in total products reached 50.9 C-mol%, which was obviously higher than that of the reported routes. Furthermore, the TOF of ethanol based on Ru metal was as high as 17.9 h−1. To our knowledge, this is the first report on ethanol synthesis from paraformaldehyde, CO2 and H2. A detailed study indicated that the outstanding results of the reaction originated from the synergy of paraformaldehyde hydrogenation, reverse water gas shift reaction and methanol homologation. [ABSTRACT FROM AUTHOR]