Reversible heterostructure CuI/CuII@BaTiO3 constructed to enhance piezocatalytic activity

Piezocatalysis has wide applications in the field of pollutant treatment. However, the catalytic activity of single piezocatalysts is limited. Constructing heterojunctions can effectively enhance its charge carrier transfer capability. In this work, CuI/CuII@BaTiO3 composites with different CuI/CuII ratios were synthesized. A high reaction rate constant of 0.0886 min−1 in the CuI/CuII@BaTiO3 (1:0.3) is obtained, which is 2.54 times than that of BaTiO3 and superior to other lead-free perovskites-based composites. The multivalent heterogeneous interfaces form different potential gradient regions, which enhance the efficient generation of superoxide radicals (•O2-), reaching approximately 2.01 times the yield of pure BaTiO3. In addition, the CuI/CuII structure serves as an active site for •O2-, facilitating the in-situ generation of hydrogen peroxide (H2O2) and triggering a Fenton-like reaction to produce hydroxyl radicals (•OH). This study provides valuable insights for the design of multi-valent heterostructure piezocatalysts for wastewater treatment applications.