Piezocatalytic H₂O₂ Production from Pure Water over a TiO₂/ZnO Heterojunction through a Dual-Channel Pathway

Piezocatalytic H2O2 generation has emerged as a promising alternative for sustainable H2O2 synthesis, yet its development is hindered by unsatisfactory energy conversion efficiency. Herein, a TiO2/ZnO piezocatalyst was developed by dispersing ZnO nanorods within a TiO2 nanosheet substrate, enabling efficient H2O2 generation in pure water. By constructing a heterostructure, we developed an effective strategy to enhance charge carrier separation and migration through a built-in electric-field-induced piezoelectric effect, thereby demonstrating the superior piezocatalytic performance of the TiO2/ZnO composite. Compared to pure TiO2 and ZnO, the TiO2/ZnO heterojunction exhibited significantly enhanced piezocatalytic H2O2 production, achieving a yield of 2078.14 μmol·g–1·h–1 in pure water, surpassing most reported piezocatalysts. Reactive species analysis revealed a dual-channel H2O2 generation mechanism, featuring an oxygen reduction reaction (ORR)-dominated pathway with a minor contribution from the water oxidation reaction (WOR). Furthermore, TiO2/ZnO exhibits excellent piezocatalytic performance in degrading various pollutants. This work provides valuable insights into piezocatalytic H2O2 generation and offers a potential pathway for the green and sustainable synthesis of H2O2.