Improved H2O2 photogeneration on KBr doped-polymeric carbon nitride via optimize the oxygen reduction path

The photosynthesis of hydrogen peroxide (H2O2) from oxygen (O2) represents a promising catalytic pathway, the limited efficiency of the oxygen reduction constitutes a primary barrier to enhancing production. In this content, alkali metal potassium (K+) and Br-doped g-C3N4 photocatalysts (K-CN) were successfully constructed by one-pot method. The introduction of K+ is not only beneficial to the transmission of space charge and the separation efficiency of photogenerated carriers, but also promotes the efficient production of H2O2 by 2e- oxygen reduction reaction. The introduction of Br- promotes O2 converted to triplet state and triggers energy transfer process to increase 1O2 production, O2 adsorption was facilitated through regulating the oxygen evolution (O2→1O2), which is beneficial to the subsequent oxygen reduction process. The results showed that the H2O2 yield of 0.05 K-CN catalyst reached 26.0 mmol g-1 h-1, which was more than 5 times that of pure g-C3N4.