Selective and Low Overpotential Electrochemical CO2 Reduction to Formate on CuS Decorated CuO Heterostructure

Cu2O/CuO/CuS electrocatalyst was prepared by thermal oxidation of cleaned copper mesh in the air into Cu2O/CuO and CuS was deposited on oxide surface using facile successive ionic layer adsorption and reaction method. The successive fabrication of the electrocatalyst was confirmed using XRD, SEM, Raman and XPS. The catalytic enhancement is believed to be associated with the reduction of copper sulfide. Together with copper oxides, they offer favorable adsorption sites for electrochemical CO2 reduction. The synthesized catalyst offered significantly enhanced activity and selectivity performance for CO2 reduction at lower overpotential. Remarkably, the faradaic efficiency for formate generation reaches 84% at the potential of − 0.7 V versus RHE. It has also provided a high partial current density of − 20 mA cm− 2

Copper and Copper-Based Bimetallic Catalysts for Carbon Dioxide Electroreduction

Among many alternatives, CO2 electroreduction (CO2ER) is an emerging technology to alleviate its level in the atmosphere and simultaneously to produce essential products containing high energy density using various electrocatalysts. Cu-based mono- and bimetallics are electrocatalysts of concerns in this work due to the material's abundance and versatility. Intrinsic factors affecting the CO2ER are first analyzed, whereby understanding and characterizing the surface features of electrocatalysts are addressed. An X-ray absorption spectroscopy-based methodology is discussed to determine electronic and structural properties of electrocatalyst surface which allows the prediction of reaction mechanism and establishing the correlation with reduction products. The selectivity and faradaic efficiency of products highly depend on the quality of surface modification. Preparation and modification of electrocatalyst surfaces through various techniques are critical to increase the number of activity sites and the corresponding site activity. Mechanisms of CO2ER are complicate and thus are discussed in accordance with main products of interests. The authors try to concisely compile the most interesting, recent, and reasonable ideas that are agreeable to experimental results. Finally, this review provides an outlook for designing better Cu and Cu-based bimetallic catalysts to obtain selective products through CO2ER