Research on cobalt-doping sites in g-C3N4 framework and photocatalytic reduction CO2 mechanism insights

The novel Co-doping combined with mesoporous g-C 3 N 4 -based photocatalyst was constructed, and the Co-CN showed impressive photocatalytic reduction CO 2 activity. Employing the DFT computation, we discussed the possible Co doping sites on g-C 3 N 4 framework, as well as the effects of band gaps, optical properties , and various densities of state (DOS) on photocatalytic activity. The adsorption energy calculation proved that the substitution and interstitial doping Co atoms in g-C 3 N 4 crystal unit cell was the stable configuration. The coexistence substitution and substitution the monolayer g-C 3 N 4 showed serious deformation. It indicated that the introduction of Co atoms leads g-C 3 N 4 molecular orbital redistribution and Co tends to occupy the conduction band, due to its weak electronegativity. Moreover, the DFT and experiment results pointed out that the doped-Co narrowed g-C 3 N 4 bandgap and increased light absorption from 450 to 800 nm, the improved charge carrier separation efficiency was originated from Co atom the unfilled 4 f and the empty 5d orbital act as electron capturing center. This research indicates the availability of transition metal g-C 3 N 4 with conducive photocatalytic activity.