Manipulating adsorbed hydrogen on lanthanum-modified CuOx: Industrial-current-density CO2 electroreduction to C2+ products or CH4

The selective electrochemical CO2 reduction reaction (CO2RR) yields valuable C2+ and C-1 products, yet the influence of adsorbed hydrogen (*H) on product distribution remains inadequately understood. This study explores this effect by developing bimetallic copper-based electrocatalysts with varied lanthanum (La) doping ratios. The oxide-derived (OD)-La-0.10-CuOx catalyst exhibits a Faradaic efficiency (FE) over 80% for C2+ products at 300 mA cm(-2), whereas OD-La-0.40-CuOx achieves a 61.4% FECH4 at 400 mA cm (-)2. Kinetic isotope experiments reveal distinct dependencies of the rate-determining steps on *H transfer for CO2RR in OD-La-0.10-CuOx and OD-La-0.40-CuOx. In situ ATR-SEIRAS and DFT calculations demonstrate that the moderate H2O dissociation capability of OD-La-0.10-CuOx lowers the energy barrier for *CHO -> *OCCHO conversion, thus increasing the FEC2+. Conversely, OD-La-0.40-CuOx, with its strong H2O dissociation capability, favors *CHO -> *CH2O, thereby promoting CO2RR-to-CH4. These findings advance the understanding of the role of *H in CO2 electroreduction at industrial current densities and present avenues for tailored CO2RR products via doping engineering.