Enhanced H₂O₂ Synthesis by Selective Electrochemical Reduction of Oxygen on Bismuth Phosphate/Oxidized Carbon Nanotube Composites.

The electrochemical two-electron oxygen reduction reaction (2e⁻ ORR) represents a promising on-site approach for the decentralized and green production of hydrogen peroxide (H₂O₂). Nevertheless, the development of efficient catalysts that exhibit high activity and selectivity remains a significant challenge. Herein, bismuth phosphate/oxidized carbon nanotube composites (BPO/CNTs-O) constructed via a simple hydrothermal method were used to generate H₂O₂ in an alkaline environment through electrocatalytic 2e⁻ ORR. With an appropriate BPO content, the BPO/CNT-O-3 catalyst demonstrated a high H₂O₂ selectivity of 91.32% at 0.40 VRHE during the rotating ring-disk electrode test. Density functional theory calculations indicate that the interaction between monoclinic BPO and CNTs-O could regulate the interfacial electronic structure and provide a suitable binding strength of oxygen (O₂) for subsequent hydrogenation to H₂O₂. In a flow-cell setup, the BPO/CNT-O-3-based cathode could provide a H₂O₂ yield of 4.0 mol g⁻ ¹ cat h⁻¹ with Faraday efficiency around 60%, and the on-site accumulated H₂O₂ could rapidly achieve organic dye degradation. This work provides a new perspective on the design and construction of electrocatalytic systems for H₂O₂ production.