An optimized heterointerface of BiVO4/C3N4 by Co single atom and F-doping for boosting photoelectrochemical water splitting

Abstract

Inefficient charge separation and surface trapping states are universal challenges for photoelectrochemical water splitting. Herein, we demonstrate an effective strategy by optimizing the band structure of the heterojunction of Co single atom-doped carbon nitride (C₃N₄) and F-doped BiVO₄ to enhance the photoelectrochemical performance of oxygen evolution. The introduction of Co single atoms enhances the surface kinetics of C₃N₄, and Co- and F-doping induces both conduction band and valence band adjustments for C₃N₄ and BiVO₄, which promotes the charge separation of photogenerated electron–hole pairs at the F-doped BiVO₄ and Co-doped C₃N₄ heterojunction. This strategy results in a reduced onset potential and a high current density of 5.89 mA cm⁻² at 1.23 V_RHE. This proof-of-principle work sheds light on rational design and fabrication of integrated photoanodes for robust solar energy conversion photoelectrodes.