A facile approach to synthesize oxygen doped g-C3N4 with enhanced visible light activity under anoxic conditions via oxygen-plasma treatment

Photocatalytic oxidation technology for the anoxic removal of organic pollutants that exist under some oxygen-free conditions is attractive but challenging. In this work, oxygen doped graphitic carbon nitride (g-C3N4) with outstanding visible light activity under anoxic conditions is synthesized via oxygen-plasma treatment for the first time. Oxygen doping does not influence the structure of g-C3N4 but changes its morphology, enhances the S-BET, decreases the band gap energy and increases the separation efficiency of photogenerated electrons and holes, which increase anoxic photocatalytic RhB degradation constants by approximately 6 times. After plasma treatment, doped oxygen not only increases the adsorption ability of g-C3N4 but also captures photogenerated electrons to reserve photogenerated holes for RhB degradation under anoxic conditions. This study provides a new insight into the design and fabrication of oxygen-free photocatalysts.