Preparation of direct Z-scheme Bi^sub 2^Sn^sub 2^O^sub 7^/g-C^sub 3^N^sub 4^ composite with enhanced photocatalytic performance

In this study, for the first time, BSO/g-C3N4 composite photocatalysts were synthesized by high temperature solid-state reaction method. The influence of systematically varied g-C3N4 contents on the photocatalytic activity was investigated in detail. The photocatalytic activity of the catalysts was evaluated through the degradation of methylene blue (MB) and acid red 18 (AR 18) as target pollutants under visible light irradiation. The results demonstrated the photocatalytic performance of the BSO/g-C3N4 composites was greatly enhanced compared to pure photocatalyst. In addition, the optimized photocatalytic efficiency for MB and AR 18 was achieved when the mass percentage of g-C3N4 in the composite was 60%. And based on our analysis, it is proposed that the BSO/g-C3N4 has the characteristic of direct Z-scheme type photocatalyst. The excellent photocatalytic performance was interpreted in terms of enhanced visible light absorption and efficient separation of electrons and holes. Compared with hydrothermal method, this method only involves sintering in air at a moderately elevated temperature, so it is efficient and more preferred for industrial scale production.