Synergetic regulation of electronic structure of graphitic carbon nitride through phosphorus and carbon co-doping for enhanced photocatalytic CO2 reduction

Abstract

Graphitic carbon nitride (CN) is a promising candidate for visible-light CO2 photoreduction, but suffers severe charge recombination due to its intrinsic π-conjugated skeleton. Herein, exogenous phosphorous (P) and carbon (C) are co-doped into the polymeric structure of CN to modulate the electronic structure. In virtue of the different electronegativity and valence electron structure of the co-dopants, an internal driving force is formed within the π-conjugated framework, which greatly accelerates the charge transfer and separation. The P and C co-doped CN (PCCN) exhibits a significantly improved CH4 evolution rate (41.85 μmol g−1h−1) under visible light irradiation, which is 12.5 times higher than the pristine CN. The P and C co-doping causes enhanced light absorption, promoted CO2 adsorption as well as inbuilt charge centers for efficient charge separation. This work offers new insights into the mutual effect of co-dopants on electronic structure rearrangement of novel photocatalysts for elevated photocatalytic activity.