Elevation of piezo-photocatalytic activity and cyclic stability via flexible PVDF@Bi2MoO6/BiOBr composite foams

The direct conversion of solar energy into chemical energy via photocatalysis or photoelectrocatalysis has attracted considerable attention for sustainable energy development and environmental remediation. However, practical implementation remains limited due to low conversion efficiency, primarily caused by severe charge carrier recombination. To overcome this challenge, piezo-photocatalysis has emerged as a promising strategy for enhancing charge separation. In this study, a poly(vinylidene fluoride) (PVDF)@Bi₂MoO₆/BiOBr heterojunction is rationally designed to improve piezo-photocatalytic performance by leveraging the built-in polarization field and promoting efficient carrier transfer. Additionally, a porous foam structure of PVDF@Bi₂MoO₆/BiOBr is fabricated via a liquid-phase method, achieving a remarkable degradation efficiency of 98.91% for basic organic dyes such as Rhodamine B (RhB) within 60 minutes. This rate is 1.67 times and 5.72 times higher than that of piezocatalysis alone (0.06649 min⁻¹) and photocatalysis alone (0.01941 min⁻¹), respectively, as demonstrated in this work. Furthermore, the degradation efficiency for various chemical contaminants consistently exceeds 80%, indicating excellent structural and operational stability. This work presents a new paradigm for the development of high-performance piezo-photocatalytic materials with potential applications in environmental purification and wastewater treatment.