EDTA-assisted synthesis of amorphous BiSx nanodots for improving photocatalytic hydrogen-evolution rate of TiO2

Compared with crystalline metal sulfides, amorphous metal sulfides can expose more unsaturated S atoms as hydrogen-production active centers to enhance photocatalytic hydrogen-evolution activity of photo-catalysts. Therefore, it is of great significance to explore simple and mild strategies to fabricate new amorphous metal sulfides for improving H-2-production performance. In this work, the amorphous BiSx nanodots with the size of 0.5-2 nm as a novel and effective H-2-evolution cocatalyst were successfully and homogeneously loaded on TiO2 surface to extremely facilitate the photocatalytic H-2-production perfor-mance. The BiSx/TiO2 photocatalyst was obtained by an EDTA-assisted two-step process, which was in-cluding the adsorption of the Bi(SIC)-EDTA ions on TiO2 and the in-situ formation of amorphous BiSx nanodots. It is found that the BiSx/TiO2(1.0 wt%) photocatalyst achieved the maximum photocatalytic hy-drogen-production performance (803.2 mu mol h(-1) g(-1), AQE=3.86%), which was 83.6 and 1.6 folds of the blank TiO2 and crystalline Bi2S3-modified TiO2 (c-Bi2S3/TiO2), respectively. Importantly, the above amorphous BiSx nanodots can serve as a general cocatalyst to promote the H-2-generation activity of other typical photo-catalysts (g-C3N4 and CdS). The boosted photocatalytic H-2-production performances are attributed to that the amorphous BiSx nanodots can provide more unsaturated active S atoms as the efficient H-2-evolution active sites for promoting H-2-evolution rate. This study provides a new insight for exploiting novel metal sulfide cocatalyst in the field of photocatalytic hydrogen evolution. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Compared with crystalline metal sulfides, amorphous metal sulfides can enhance photocatalytic hydrogen-evolution activity by providing more unsaturated S atoms. In this study, amorphous BiSx nanodots were successfully loaded on TiO2 surface as an efficient H-2-evolution cocatalyst, significantly boosting the photocatalytic H-2-production performance. Additionally, the amorphous BiSx nanodots can also serve as a general cocatalyst to promote the H-2-generation activity of other typical photo-catalysts.