Construction of Z-scheme Ag2CO3/N-doped graphene photocatalysts with enhanced visible-light photocatalytic activity by tuning the nitrogen species

摘要

Semiconductor-based photocatalysis has great potential in various environmental and energy applications, and Z-scheme photocatalysts have many advantages over single-component photocatalysts. The construction of a highly efficient Z-scheme photocatalytic system depends on the geometric structure arrangement, microscopic and crystalline form of the stoichiometric species, and it has not been elucidated whether the Z-scheme photocatalysts can be designed by tuning the electronic structures of cocatalysts alone. Here, using N-doped graphene (NG) as cocatalyst, we successfully constructed Z-scheme Ag2CO3-NG photocatalysts with enhanced activity for the photooxidative degradation of phenol pollutant. It was found that the pyridinic nitrogen species (N-p) of NG could spontaneously reduce Ag+ to produce plasmonic Ag nanoparticles on Ag2CO3-NG, while the efficiency of the photogenerated charge separation, Z-scheme transfer option, and O-2 adsorption were promoted by the graphitic nitrogen species (Ng). Therefore, the as-designed Z-scheme Ag2CO3-NG photocatalysts showed much higher activity than Ag2CO3 and its composites with graphene oxide (GO) or reduced GO as cocatalysts in the photocatalytic degradation of phenol. Hence, our results provide a new strategy for exploring advanced Z-scheme photocatalysts with NG as cocatalyst by rationally tuning the No and Ng species. (C) 2016 Elsevier B.V. All rights reserved.