Anchoring Ag Atom on Carbon Vacancy Enriched Carbon Nitride to Synergistically Promote CO₂ Photoredution with Water

Abstract

Pristine carbon nitride (CN) has low CO2 reduction ability due to its sluggish charge carriers transfer and CO2 activation. Herein, carbon vacancy (CV) and Ag single atoms (SAs) with N2 coordination are simultaneously introduced into CN with the ordered structure for stable and efficient photoreduction of CO2 in the presence of H2O. The optimal sample loaded with 0.053 wt.% Ag evolve 173.0 µmol g−1 CO in 3 h with 89% selectivity, which is 11.7 times higher than that of pristine CN (14.7 µmol g−1). Experiments and theoretical calculations reveal that the CV and Ag–N2 sites promote CO2 adsorption/activation and the generation of *COOH and *CO. KSCN‐assisted calcination induces more ordered arrangement of melon chains, which can accelerate charge transfer/separation and facilitate H2O oxidation, thus accounting for the largely improved CO2 photoreduction performance. This study adopts a new method to prepare Ag SA‐anchored and C‐deficient CN, and provides insights into their synergistic roles in enhancing CO2 reduction.