Boosting piezo-photocatalytic activity of BiVO4/BiFeO3 heterojunctions through built-in polarization field tailoring carrier transfer performances

Abstract

The greatest challenge that limits the application of piezo-photocatalytic materials is the low separation efficiency of the generated electron-hole pairs, resulting in poor catalytic activity. Here, the semiconductor n-p heterojunctions BiVO4/BiFeO3 (BVO/BFO) were designed to enhance its piezo-photocatalytic processes. Under the excitation of piezo-vibration and the irradiation of visible light, the BVO/BFO heterojunctions exhibited ultra-high and stable piezo-photocatalytic performance with the degradation rate of Rhodamine B (RhB) solution up to 98 %, and its k value was 6.12 times than that of photocatalysis and 4.36 times than that of piezoelectric catalysis. Thanks to the n-type BVO nanoparticles with good crystallinity were uniformly distributed on the surface of the p-type piezoelectric material BFO, the built-in polarization field was formed and be advantageous to improve the carrier transport performances. A large electron diffusion coefficient (27.44 × 103 cm2·s−1), effective diffusion length (14.49 cm), and long electron lifetime (7.66 × 10-3 s) were achieved in the BVO/BFO heterojunctions, which played important roles to boost the piezo-photocatalytic activity. The preparation of BVO/BFO heterojunctions and their remarkable photo-piezoelectric properties provides a theoretical and practical reference for the development of efficient piezo-photocatalysis to apply in environmental remediation.