Tuning the ratio of Bi/Bi2O3 in Bi/PNC nanosheet for high-efficiency electrosynthesis hydrogen peroxide

Electrocatalytic two-electron oxygen reduction reaction (2e− ORR) is a promising method for producing green and sustainable H2O2 but lacks high selectivity and yields electrocatalysts. And it is critical to develop catalysts that meet industrial demands. Herein, we report the different ratios of Bi0/Bi3+ supported on a phosphorus, nitrogen, and carbon nanosheet (Bi/PNC), which can reduce O2 to H2O2 with high selectivity (up to 97.75% at 0.4 VRHE) in 0.1 M KOH electrolyte and retain 97% selectivity even after 100 h electrolysis. Then a homemade flow-cell system was built for electrocatalytic production of H2O2 under an O2 atmosphere using an improved gas diffusion electrode. The Bi/PNC-4 can achieve a high H2O2 yield of 2.76 mol·g catalyst −1 ·h−1 (alkaline), 5.29 mol·g catalyst −1 ·h−1 (neutral), and 3.50 mol·g catalyst −1 ·h−1 (acid) in universal pH conditions. The in-situ generated H2O2 can function as a degradation agent for efficiently degrading pesticides and antibiotics. The outstanding selectivity and activities are attributed to the synergistic effects of Bi0 and Bi3+ that promote proton-coupled reduction of O2 to OOH* (ΔGOOH* = 4.27 eV), and the formation of H2O2. The fast yield of H2O2 on Bi/PNC catalysts in flow-cell provides a promising path of electrocatalytic 2e− ORR for practical H2O2 production.