Harvesting Vibration Energy to Produce Hydrogen Peroxide with Bi₃TiNbO₉ Nanosheets through a Water Oxidation Dominated Dual-Channel Pathway

Developing green, efficient, and sustainable techniques to synthesize hydrogen peroxide has always been the challenge faced by researchers. The rising-star piezocatalysis has been demonstrated to be capable of drive redox reactions based on the piezoelectric effect and therefore may provide novel solutions for H2O2 production through mechanical energy conversion. Herein, the bismuth layered compound Bi3TiNbO9 (BTNO) was utilized to produce H2O2 by harvesting ultrasound vibration in a pure water system for the first time. A yield rate of 407.05 mu mol center dot g-1 center dot h-1 was achieved under ultrasonic conditions (40 kHz, 50 W) without any cocatalysts and scavengers, surpassing the majority of the reported piezocatalysts with similar mechanisms. Furthermore, a satisfied circulation and long-term running stability of piezocatalyst BTNO were proved, and the accumulated concentration of H2O2 could reach 1127 mu M after 5 h of reaction. The satisfied piezoelectric response of BTNO was demonstrated by piezoresponse force microscopy (PFM), electrochemical characterization, and piezodeposition experiments. On the basis of band structure analysis, the possible pathway of generating hydrogen peroxide by piezocatalysis with BTNO was proposed according to the radical-trapping and atmosphere control experiment results. It was found that both the water oxidation reaction (WOR) and oxygen reduction reaction (ORR) contributed to the yield of H2O2, but direct WOR plays an absolute dominant role. In addition, Ar sparging was verified to be able to efficiently enhance the generation of H2O2 due to the enlarged cavitation effect, and piezocatalysis of BTNO was found to be superior to its photocatalysis in synthesizing H2O2. It is hoped that this work can provide deep insights into piezocatalysis for H2O2 generation and offer clues for the green, sustainable synthesis of hydrogen peroxide.