In situ reconstruction of Bi nanoparticles confined within 3D nanoporous Cu to boost CO2 electroreduction

Due to the low efficiency of a single metal Bi in the CO2 reduction reaction (CO2RR) to formates, enhancing the conductivity and yield through surface engineered composites is an alluring approach. In this study, we reconstruct Bi nanoparticles in situ growth in 3D nanoporous copper structures. Benefiting from the 3D nanoporous conductive network and the strong interaction between Cu and Bi, the Fermi level becomes shifted upward and the resulting Bi@np-Cu displays a surprising CO2RR performance. Bi@np-Cu demonstrates a formate faradaic efficiency of 97.7% at a potential of −0.97 V vs. reversible hydrogen electrode with a remarkable current density of 82 mA cm−2. Importantly, this catalyst also has a faradaic efficiency of more than 90% for a continuous CO2RR of 40 h. Density function theory calculations reveal that np-Cu effectively modulates the electronic states of Bi, optimizing the intermediate adsorption energy and leading to increased intrinsic activity of Bi. This study provides a novel perspective on the applications of nanoporous metals in catalysis.