Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported onto CO2 Capture Materials

Cu is a unique catalyst for CO₂ electroreduction, since it can catalyze CO₂ reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO₂ is considered to facilitate the activity and selectivity of CO₂ reduction. Herein, a new strategy is presented for CO₂ reduction with improved C₂ H₄ selectivity on a Cu catalyst by using CO₂ capture materials as the support at ambient pressure. N-doped carbon (N_x C) was synthesized through high-temperature carbonization of melamine and l-lysine. We observed that the CO₂ uptake capacity of N_x C depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600-800 °C). The as-prepared CuO/N_x C catalysts exhibit a considerably higher C₂ H₄ faradaic efficiency (36 %) than CuO supported on XC-72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C₂ H₄ faradaic efficiency and CO₂ uptake capacity of the supports for CuO. The local high CO₂ concentration near Cu catalysts, created by CO₂ capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C₂ H₄ . This study demonstrates that pairing Cu catalysts with CO₂ capture supports is a promising approach for designing highly effective CO₂ reduction electrocatalysts.