Crystal Engineering of BiVO4 for Photochemical Sensing of H2S Gas at Ultra-low Concentration

We report a photochemical bismuth vanadate (BiVO₄) sensing material, which possesses a large proportion of (110) and (011) facets combined with the additional (111) facets, for the selective detection of ultra-low concentration hydrogen sulfide (H₂S) driven by visible light. Specifically, the obtained octadecahedron BiVO₄ (Octa-BiVO₄) performs a high response value (67) and short response time (47.4 s) to 100 ppm H₂S with good stability for nearly 100 days, as well as undisturbedness by moist air. With the combination of experimental and theoretical calculation results, the adsorption and carrier transfer behaviors of H₂S molecules on the Octa-BiVO₄ crystal surface are investigated. By adjusting the ratio of different crystal facets and controlling the facets with characteristic adsorption, we achieve improved anisotropic photoinduced carrier separation and high selectivity for a specific gas. Furthermore, this facial facet engineering can be extended to the synthesis of other sensing materials, offering huge opportunities for fundamental research and technological applications.