Direct low concentration CO2 electroreduction to multicarbon products via rate-determining step tuning

Direct converting low concentration CO 2 in industrial exhaust gases to high-value multi-carbon products via renewable-energy-powered electrochemical catalysis provides a sustainable strategy for CO 2 utilization with minimized CO 2 separation and purification capital and energy cost. Nonetheless, the electrocatalytic conversion of dilute CO 2 into value-added chemicals (C 2+ products, e.g., ethylene) is frequently impeded by low CO 2 conversion rate and weak carbon intermediates’ surface adsorption strength. Here, we fabricate a range of Cu catalysts comprising fine-tuned Cu(111)/Cu 2 O(111) interface boundary density crystal structures aimed at optimizing rate-determining step and decreasing the thermodynamic barriers of intermediates’ adsorption. Utilizing interface boundary engineering, we attain a Faradaic efficiency of (51.9 ± 2.8) % and a partial current density of (34.5 ± 6.4) mA·cm −2 for C 2+ products at a dilute CO 2 feed condition (5% CO 2 v/v), comparing to the state-of-art low concentration CO 2 electrolysis. In contrast to the prevailing belief that the CO 2 activation step ( \({{CO}}_{2}+{e}^{-}+\, * \,\to {}^{ * }{CO}_{2}^{-}\) ) governs the reaction rate, we discover that, under dilute CO 2 feed conditions, the rate-determining step shifts to the generation of *COOH ( \({}^{ * } {{CO}}_{2}^{-}+{H}_{2}O\to {}^{ * } {COOH}+{{OH}}^{-}({aq})\) ) at the Cu 0 /Cu 1+ interface boundary, resulting in a better C 2+ production performance.