Crucial Effect of Halogen on the Photocatalytic Hydrogen Evolution for Bi₁₉X₃S₂₇ (X = Cl, Br) Nanomaterials

Abstract

Halogen has a significant effect on the photocatalytic performance of bismuth chalcohalide (Bi19X3S27, X = Cl, Br), which is a class of unique material that holds a bright future and is used in hydrogen energy evolution. To systematically research the influence of halogen, the hydrogen evolution of Bi19X3S27, which has not been identified yet, was studied in this work rigorously. The Bi19Br3S27 sample prepared at 200 °C possessed optimal crystallinity and hydrogen evolution rate of 466.7 μmol g–1 h–1, higher than that of samples prepared at other temperatures. It is worth mentioning that with the rising of temperature, both metallic bismuth and sulfur vacancies accepted electrons during the photocatalytic process, thus hindering hydrogen evolution. For Bi19Cl3S27 nanorods, the sample synthesized at 180 °C showed the best activity of 195.1 μmol g–1 h–1; this performance distinction is attributed to the different properties of halogen. Compared with BiOBr on hydrogen evolution ability, Bi19Br3S27 is also far ahead, illustrating the disparity of sulfide and oxide. This study provided a systematic research of restricted and rarely reported Bi19X3S27 materials and opened the door for further thorough and deep exploration of Bi19X3S27.