Supercritical CO2-Tailored 2D Oxygen-doped Amorphous Carbon Nitride for Enhanced Photocatalytic Activity

Abstract

Simultaneously adjusting the surface, crystallographic and electronic structures of nanomaterials provide a new avenue for rational design of advanced photocatalyst yet it is challenging. In this work, a surface and structural engineering strategy is developed to simultaneously realize the 2D amorphous structure and oxygen (O)-doping in graphitic carbon nitride (g–C3N4) via the assistance of supercritical carbon dioxide (SC CO2). The 2D O-doped amorphous g–C3N4 nanosheets display greatly enhanced photocatalytic CO2 reduction and methylene blue degradation performances. The synthesis method as well as the mechanism of the enhanced photocatalytic activity was investigated, wherein the introduction of 2D amorphous structure and O dopant in the g–C3N4 contributes to the increased surface area, abundant active sites, wider visible-light absorption range and efficient charge separation property, and thus the outstanding photocatalytic activities can be obtained. Its photocatalytic CH4 evolution rate and MB degradation rete are 5.1 and 7.0 times enhancement over bulk crystalline g–C3N4, respectively. This work presents a great promising way for designing and developing advanced photocatalysts.