Electrochemical Reduction of CO With Good Efficiency on a Nanostructured Cu-Al Catalyst.

Carbon monoxide (CO) and formic acid (HCOOH) are suggested to be the most convenient products from electrochemical reduction of CO according to techno-economic analysis. To date, tremendous advances have been achieved in the development of catalysts and processes, which make this research topic even more interesting to both academic and industrial sectors. In this work, we report nanostructured Cu-Al materials that are able to convert CO to CO and HCOOH with good efficiency. The catalysts are synthesized a green microwave-assisted solvothermal route, and are composed of CuO crystals modified by Al. In KHCO electrolyte, these catalysts can selectively convert CO to HCOOH and syngas with H/CO ratios between 1 and 2 approaching one unit faradaic efficiency in a wide potential range. Good current densities of 67 and 130 mA cm are obtained at -1.0 V and -1.3 V vs. reversible hydrogen electrode (RHE), respectively. When switching the electrolyte to KOH, a significant selectivity up to 20% is observed for CH formation, and the current densities achieve 146 and 222 mA cm at -1.0 V and -1.3 V vs. RHE, respectively. Hence, the choice of electrolyte is critically important as that of catalyst in order to obtain targeted products at industrially relevant current densities.