Fragmented Polymetric Carbon Nitride with Rich Defects for Boosting Electrochemical Synthesis of Hydrogen Peroxide in Alkaline and Neutral Media.

Electrocatalytic oxygen reduction reaction via 2e^- pathway is a safe and friendly route for hydrogen peroxide (H₂O₂) synthesis. In order to achieve efficient synthesis of H₂O₂, it is essential to accurately control the active sites. Here, fragmented polymetric carbon nitride with rich defects (DCN) is designed for H₂O₂ electrosynthesis. The multi-type defects, including the sodium atom doping in six-fold cavities, the boron atom doping at N-B-N sites and the cyano groups, are successfully created. Owing to the synergistic effect of these defects, the fragmented DCN achieves a high H₂O₂ production rate of 2.28 mol g_cat. ^-1 h^-1 and a high Faradic efficiency of nearly 90 % in alkaline media at 0.4 V vs. RHE in H-type cell. In neutral media, the H₂O₂ concentration produced by DCN can reach 1815 μM within 6 h at a potential of 0.2 V vs. RHE, and the H₂O₂ production rate of DCN is 0.23 mol g_cat. ^-1 h^-1. In addition, DCN shows excellent long-term durability in alkaline and neutral media. This study provides a new approach for the development of the boron, nitrogen doped carbon-based electrocatalysts for H₂O₂ electrochemical synthesis.