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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]

Electrocatalytic CO2 reduction reaction has been considered as a promising route to realize carbon cyclic utilization and renewable energy storage. Recently, Zn-based catalysts have attracted much attention due to their earth-abundant reserve and low cost, which can meet the demand for commercial applications at a large scale. Herein, ZnO catalyst (ZIF-8-D-ZnO) was synthesized by pyrolysis of ZIF-8 precursor for electrocatalytic reduction of CO2. The ZIF-8-D-ZnO catalyst exhibits an excellent catalytic activity for CO production than rod-like ZnO and Zn foil catalysts, with faradaic efficiency of 86.7 % and geometric current density of 16.1 mA cm−2 at −1.2 V (vs. RHE). Moreover, the overpotential over ZIF-8-D-ZnO is much lower than that of analogous catalysts. The results suggest that the grain boundaries within the porous structure facilitate CO2 electroreduction over ZIF-8-D-ZnO due to the introduction of new catalytically active sites. This work provides experimental evidence for the design of efficient Zn-based materials for CO2 electrocatalytic reduction. ZIF-8-D-ZnO catalyst with porous structure and grain boundaries exhibits much higher CO faradaic efficiency and current density than ZnO-R and Zn foil catalysts. [ABSTRACT FROM AUTHOR]

Cu 2+ -based materials, a class of promising catalysts for the electrocatalytic carbon dioxide reduction reaction (CO 2 RR) to value-added chemicals, usually undergo inevitable and uncontrollable reorganization processes during the reaction, resulting in catalyst deactivation or the new active sites formation and bringing great challenges to exploring their structure-performance relationships. Herein, a facile strategy is reported for constructing Cu 2+ and 3, 4-ethylenedioxythiophene (EDOT) coordination to stabilize Cu 2+ ions to prepare a novel layered coordination polymer (CuPEDOT). CuPEDOT enables selective reduction of CO 2 to CH 4 with 62.7% Faradaic efficiency at the current density of 354 mA cm -2 in a flow cell, and the catalyst is stable for at least 15 h. In situ spectroscopic characterization and theoretical calculations reveal that CuPEDOT catalyst can maintain the Cu 2+ -EDOT coordination structurally stable in CO 2 RR and significantly promote the further hydrogenation of *CO intermediates, favoring the formation of CH 4 instead of dimerization to C 2 products. The strong coordination between EDOT and Cu 2+ prevents the reduction of Cu 2+ ions during CO 2 RR. The finding of this work provides a new perspective on designing molecularly stable, highly active catalysts for CO 2 RR., (© 2023 Wiley-VCH GmbH.)