Bulk polarization fields and interfacial electron sink in MXene-modified iodine-doped Bi4Ti3O12 enhance piezocatalytic H2O2 generation

Abstract Piezocatalytic hydrogen peroxide (H2O2) production holds promise as a sustainable technology, but its practicability is hindered by inadequate polarization fields, sluggish charge transport, and rapid bulk carrier recombination. Herein, we propose a catalyst-design strategy integrating bulk iodine doping with surface MXene cocatalyst coupling in a typical piezoelectric bismuth titanate (Bi4Ti3O12, BTO). This design generates intensified bulk polarization fields that markedly suppress electron-hole recombination, while MXene functions as an efficient interfacial electron sink, significantly reducing surface kinetic barriers by facilitating electron transfer for the oxygen reduction reaction (ORR). The optimized iodine-doped MXene-coupled BTO (MBTO-I) catalyst demonstrates a piezocatalytic H₂O₂ production rate of 5890 µmol g⁻¹ h⁻¹ under ambient conditions without any sacrificial agents. Theoretical calculations and advanced characterization techniques reveal that iodine doping effectively lowers energy barriers for *OH intermediate formation and stabilizes O–H bonds, while MXene coupling significantly improves interfacial charge transfer and accelerates the ORR kinetics. Furthermore, the produced H2O2 was successfully employed for bacterial sterilization and rapid degradation of pollutants. Subsequent chemical analyses and biological assessments confirm a substantial reduction in the toxicity of sulfamethoxazole (SMX) degradation products, highlighting the catalyst’s considerable potential for environmental remediation applications.