Visible-Light-Driven Gas-Phase Hydrogen Sulfide Decomposition using Organic-Inorganic Hybrid Photocatalysts

Hydrogen sulfide (H2S) is a toxic gas generated by chemical and geothermal power plants and has an unpleasant odor. Even low concentrations of H2S can cause odor problems upon release into the atmosphere; therefore, the efficient removal of H2S is required. Photocatalytic H2S decomposition methods have been extensively investigated because they are energy-efficient; however, most methods involve the degradation of a sacrificial reagent after alkaline adsorption and gas-phase decomposition at relatively high concentrations of 100 ppm or more. Although H2S decomposition by TiO2 under low-concentration conditions has been reported, H2S is decomposed by ultraviolet (UV) light irradiation because TiO2 is unresponsive to visible light. In this study, a composite catalyst is synthesized to achieve the gas-phase decomposition of low-concentration hydrogen sulfide under visible light. By combining carbon nitride (g-C3N4) with a cadmium sulfide (CdS) photocatalyst, a g-C3N4/CdS catalyst is obtained, which reduces 10 ppm H2S to less than 1 ppm. This effective and simple photocatalyst is suitable for mitigating the odor issue related to H2S.