Boosting charge transfer in Au-decorated B/K co-doped CN nanosheets towards enhanced photocatalytic CO2 reduction

Abstract

Graphitic carbon nitride (CN)-based photocatalysts have received widespread attention for photocatalytic CO₂ reduction. However, their activity is still insufficient due to the high recombination rate of photogenerated carriers and limited active sites. Here, we construct an Au nanoparticle modified B/K co-doped CN (Au/BKCN) photocatalyst for photocatalytic CO₂ reduction. The B and K doping can accelerate exciton dissociation and promote the charge transport, thus effectively improving the separation efficiency of photo-induced electrons and holes. The Au nanoparticles not only promote the interfacial charge transfer but also provide more reactive sites for photocatalytic CO₂ reduction, thereby synergistically improving photocatalytic CO₂ activity. Thanks to the synergistic effects of Au loading and B/K co-doping, the optimal 1% Au/BKCN catalyst demonstrates a considerable CO production rate of 11.56 μmol g⁻¹ h⁻¹, which is about 7-fold enhanced compared to that of the bare CN. This work provides a new strategy to enhance the photocatalytic CO₂ reduction activity of CN-based photocatalysts via element doping and cocatalyst decoration.