Single-atom Nb anchored on graphitic carbon nitride for boosting electron transfer towards improved photocatalytic performance

Single-atom Nb anchored on g-C3N4 was prepared by facile thermal polymerization. Compared with pure g-C3N4, optimized Nb-anchoring samples exhibited excellent CO and CH4 yield and higher photocatalytic oxidation efficiency in degrading amoxicillin (AMX). Combining DFT calculations and experimental results, the enhanced photocatalytic performance was attributed to anchored single-atom Nb in terms of Nb-C and the formation of N defects. Anchoring with single-atom Nb contributed to the formation of N defects in g-C3N4, inducing the formation of polarized Nb-C bonds with high conductivity accelerating the directional transfer of photogenerated electrons and holes. Moreover, this restrained the relatively high charge carrier recombination rate of g-C3N4. Additionally, N defects with solitary electrons could enhance the charge density and serve as active centers for a photocatalytic reaction. The present work underlines the importance of the synergistic effect of anchoring Nb and simultaneously generating N defects for developing a new generation of g-C3N4-based photocatalysts.