Tuning of Surface Wettability and Interfacial Electron Transfer in Cupric Oxide Nanosheets for Highly Efficient Hydrogen Peroxide Production and Electro-Fenton Catalysis

Hydrogen peroxide (H 2 O 2 ), as a versatile and environmentally friendly oxidant, has drawn increasing attention in energy and environmental applications. Aiming at boosting the in situ electrocatalytic H 2 O 2 production and activation toward water purification, we developed a two-dimensional (2D) CuO nanosheet-modified activated carbon fiber (CuO NSs/ACF) bifunctional free-standing hybrid composite electrode. The introduction of 2D CuO NSs well modulated the electronic structure and surface wettability of hybrid electrodes, promoting the two-electron oxygen reduction reaction (ORR) for H 2 O 2 generation and the following CuO-catalyzed Fenton efficiency. Taking bisphenol A (BPA) as the target pollutant, the BPA degradation and TOC removal could reach 99.45 and 74.04%, respectively, after 30 min electrolysis. We identified the reactive oxygen species ( • OH and • O 2 – ) produced in the CuO NSs/ACF system and further discussed the tuning mechanisms. This work provided a promising 2D material modification strategy for boosting in situ electrochemical H 2 O 2 production and electro-Fenton activity and facilitating its application for water purification.