Synergistically boosted photocatalytic production of hydrogen peroxide via protonation and oxygen doping on graphitic carbon nitride

Photocatalytic synthesis of hydrogen peroxide (H2O2) using modified graphitic carbon nitride (g-C3N4) has been recognized as a promising green and sustainable process. However, the effect of g-C3N4 modification on the surface properties of photocatalytic surface reactions still needs extended exploration. In this work, we design and synthesize a protonation induced oxygen doping in g-C3N4 (pCN1), which shows uniquely curled nanosheet structures in microscopic level. Under visible light irradiation, the photocatalytic H2O2 production rate of pCN1 reaches 707 μmol g−1 h−1, which is approximately eight times higher than that of primitive g-C3N4. The enhanced photocatalytic performance is attributed to the synergistic effect of protonation and oxygen doping, which not only dramatically facilitates the adsorption of oxygen molecules and the desorption of H2O2 product, but also promotes the charge separation. In addition, more abundant protons supplied via protonation process can combine with the adjacent oxygen atoms on catalyst surface, thus promoting the formation of OOH* intermediate and improving the H2O2 yield. This work provides a facile and effective strategy to prepare highly-efficient modified g-C3N4 photocatalyst for the clean and convenient synthesis of H2O2.