Heterojunction photocatalyst of cavity shaped Bi2S3/g-C3N4 for bisphenol a degradation: Regulation of internal electric field via assistance of interfacial functional groups

The p-n heterojunction with internal electric field (IEF) is flourishingly developed in photocatalysis. Enlarging the space charge region width can effectively improve the migration/separation of charge carriers. Here, adequate functional groups (–COOH, -N-(C)3, -C-N–H) were generated from graphitic carbon nitride (GCN) decomposition, worked as the dispersant and electric charge contributor in the heterojunction. Bi ions were adsorbed on –COOH to achieve localized nucleation, formed Bi2S3 can be uniformly dispersed on GCN surface to form FGBS/GCN. Additionally, the incorporation of functional groups not only ameliorated the 3D cavity structure and optimized the band structure of functional groups modified Bi2S3 (FGBS) but also widened the space charge region of IEF in FGBS/GCN and resulted in efficient carriers separation. Benefit from functional groups, the initial rate of bisphenol A (BPA) degradation over 2FGBS/GCN was 0.0280 mmol⋅gcat-1⋅h−1. This work provides new insight into the regulation of the space charge region in the p-n heterojunction.