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.