In-situ fabrication of Bi2S3/g-C3N4 heterojunctions with boosted H2 production rate under visible light irradiation

The limited response region of visible light and the fast recombination of photo-induced carriers severely confine the photocatalytic behavior of the original g-C3N4. In this work, using thioureas and bismuth citrate as precursors, Bi2S3/g-C3N4 heterojunction photocatalytic materials were successfully in-situ constructed by a one-step solid phase method. Suffering from 4 h visible-light shining, the amount of H2 evolution over 1.5 wt% Bi2S3/g-C3N4 heterojunctions has reached 826.2 μmol·g−1, and the H2 production rate over Bi2S3/g-C3N4 heterojunctions achieves 236.1 μmol·g−1·h−1, which is 7 times as high as that of the pure g-C3N4. Construction of Bi2S3/g-C3N4 not only adjusts the band structures but also improves the visible light response capacity of g-C3N4. The rapid transfer of photogenerated charge pairs between Bi2S3 and g-C3N4 interfaces facilitates the separation of photo-excited charge pairs, sequentially boosting the photocatalytic H2 production rate. Combined with the various characterization and analysis results, the reasonable and possible mechanism for enhancement in the performance of Bi2S3/g-C3N4 heterojunction photocatalytic materials was proposed. This work offers potential insight into the boosted photocatalytic performance of g-C3N4 for H2 production exposure to visible light by constructing the heterojunctions to efficiently separate the photo-induced charge pairs.