An Innovative Approach to Precisely Tailor the Composition of Syngas in CO2 Electroreduction

Syngas production through CO2 electrochemical reduction reaction (CO2RR) has attracted numerous attention for reducing carbon emissions and increasing chemical feedstocks. However, the precise regulation of H2/CO molar ratio in syngas remains a challenge, especially through simple and feasible methodologies. In this work, a novel composite electrocatalyst, copper-indium/black phosphorus (CuIn/BP) is developed, using a simple one-step co-reduction method for efficient CO2RR. It is found for the first time that there is a linear relationship between BP content in CuIn/BP and the H2/CO molar ratio in syngas. Consequently, the H2/CO molar ratio in syngas can be precisely tailored by simply adjusting the BP content in CuIn/BP. A total faradaic efficiency (FE) of CO and H2 reached ≈ 100% along with a current density of 135.2 mA cm-2. Mechanistic studies suggest that the CuIn phase and Cu3P species are in situ generated in CuIn/BP, where the CuIn phases mainly contribute to CO generation, while the Cu3P species promote H2 formation. The variation in BP content modulates the proportion of the CuIn phase and Cu3P species, leading to the variations in H2/CO molar ratios. Thus, this study provides an efficient and simple strategy to tailor the H2/CO molar ratio in syngas for various industrial applications.