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

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.