Dual-pathway self-promoting piezocatalytic H2O2 generation over Bi5Ti3FeO15 nanofibers and the mechanism

Abstract

Piezocatalytic hydrogen peroxide (H₂O₂) generation is a promising synthesis method that has received increasing attention; however, the reaction pathway requires further investigation. Here, Bi₅Ti₃FeO₁₅ nanofibers are used to generate H₂O₂ by harvesting mechanical energy, and the reaction pathways are investigated. The H₂O₂ yield over Bi₅Ti₃FeO₁₅ nanofibers steadily increases from 331 μmol g⁻¹ h⁻¹ in the first cycle to 746 μmol g⁻¹ h⁻¹ in the tenth cycle in pure water without a sacrificial agent. Reliable reaction pathways are revealed by monitoring the pH value changes in the reaction solution during the H₂O₂ generation process. In the H₂O₂ generation process, the water oxidation reaction (WOR) provides a large amount of H⁺ in the reaction solution, which promotes the oxygen reduction reaction (ORR) for H₂O₂ generation. Therefore, an efficient synergistic effect between ORR and WOR achieves dual-pathway H₂O₂ generation, contributing to the excellent piezocatalytic performance of Bi₅Ti₃FeO₁₅ nanofibers. Furthermore, mechanistic studies indicate that the piezocatalytic H₂O₂ generation follows the energy band theory. This work not only demonstrates Bi₅Ti₃FeO₁₅ nanofibers as efficient piezocatalysts for H₂O₂ generation but also provides a simple and effective approach to elucidate reaction pathways. This approach can be applied in photocatalytic, tribocatalytic, and electrocatalytic H₂O₂ generation.