Manipulating adsorbed hydrogen on lanthanum-modified CuOx: Industrial-current-density CO2 electroreduction to C2+ products or CH4
Zeyu Guo, Huiwen Zhu, Zijun Yan, Lei Lei, Degao Wang, Zhenfeng Xi, Yirui Lian, Jiahui Yu, Kam Loon Fow, Hainam Do, Jonathan D. Hirst, Tao Wu, Mengxia Xu
Abstract
The selective electrochemical CO 2 reduction reaction (CO 2 RR) yields valuable C 2+ 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 -CuO x catalyst exhibits a Faradaic efficiency (FE) over 80% for C 2+ products at 300 mA cm −2 , whereas OD-La 0.40 -CuO x achieves a 61.4% FE CH4 at 400 mA cm −2 . Kinetic isotope experiments reveal distinct dependencies of the rate-determining steps on *H transfer for CO 2 RR in OD-La 0.10 -CuO x and OD-La 0.40 -CuO x . In situ ATR-SEIRAS and DFT calculations demonstrate that the moderate H 2 O dissociation capability of OD-La 0.10 -CuO x lowers the energy barrier for *CHO → *OCCHO conversion, thus increasing the FE C2+ . Conversely, OD-La 0.40 -CuO x , with its strong H 2 O dissociation capability, favors *CHO → *CH 2 O, thereby promoting CO 2 RR-to-CH 4 . These findings advance the understanding of the role of *H in CO 2 electroreduction at industrial current densities and present avenues for tailored CO 2 RR products via doping engineering. Tuneable electrochemical CO 2 dimerization to C 2+ products or hydrogenation to CH 4 is achieved by adjusting the adsorbed hydrogen on La-CuO x catalysts with different La-doping ratio. • Selective CO 2 RR to C 2+ or CH 4 is achieved by tuning La doping in La-CuO x catalysts. • La doping enhances H 2 O dissociation capacity, increasing surface-adsorbed hydrogen. • Adsorbed hydrogen manipulates *CHO dimerization to C 2+ and hydrogenation to CH 4 . • OD-La 0.10 -CuO x achieves FE > 80% for C 2+ through enhanced *CHO dimerization to *OCCHO. • OD-La 0.40 -CuO x achieves FE > 60% for CH 4 through enhanced *CHO hydrogenation to *CH 2 O.