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.