Anodic Water Oxidation to H₂O₂ on O_v-Rich ZnO Nanoparticles for Degradation of Tetracycline

The electrochemical two-electron water oxidation reaction (2e–WOR) provides a state-of-the-art alternative for the generation of hydrogen peroxide (H2O2). However, previously reported water oxidation catalysts cannot simultaneously achieve both high selectivity and high H2O2 yield, which constitutes a bottleneck for the widespread application of this technology. In this study, a cost-effective pyrolysis technique was used to prepare zinc oxide nanoparticles enriched with oxygen vacancy defects, which were loaded onto the surface of a three-dimensional conductive carbon cloth to prepare an environmentally friendly eco-electrocatalyst. Density functional theory calculations for determining the Ov content on the surface of ZnO(002) indicated a continuous increase in the level of Ov, which played a crucial role in regulating the free energy of adsorption of oxygen intermediates associated with the competitive four-electron water oxidation reaction pathway. Due to the enhanced ZnO selectivity, superior carbon fiber conductivity, promoted active site exposure, and three-dimensional structure mass transfer, the ZnO/CC-450 electrode exhibited preeminent 2e–WOR performances with high selectivity (72.34% at 2.8 V vs RHE), a vigorous H2O2 generation rate (17.32 μmol cm–2 min–1), and robust stability. The work provides a comprehensive insight into an efficient, promising, and cost-effective approach for in situ generation of hydrogen peroxide with simple preparation, facilitating a wide application prospect.