Single-atom nickel sites boosting Si nanowires for photoelectrocatalytic CO 2 conversion with nearly 100% selectivity.

It is a challenge to design a photocathode with well-defined active sites for efficient photoelectrocatalytic CO 2 reduction. Herein, single-atom Ni sites are integrated into Si nanowires to develop a novel photocathode, denoted as Ni-NC/Si. The photocathode demonstrates a stable faradaic efficiency for CO production, approaching nearly 100% at -0.6 V vs. RHE. The introduction of single-atom Ni sites provides sufficient active sites for CO 2 reduction, thereby improving the selectivity towards CO formation.