Photocatalytic Gas-Phase Hydrogen Sulfide Removal Using Mo Cocatalyst: Implementation of Counter-Poisoning Photocycle.

Hydrogen sulfide is a toxic gas known for its foul odor and health risks, even at significantly low concentrations. Although its decomposition at high concentrations is common in industrial processes, decomposing it at low concentrations is difficult. One of the difficulties is that sulfate ions generated during the reaction would poison the catalyst and reduce efficiency. Here, we show the gas-phase decomposition of low-concentration hydrogen sulfide using a high-activity photocatalyst, and to counter the poisoning problem, molybdenum is introduced through a novel photosupporting method that utilizes the characteristics of photocatalysts. In this study, we demonstrate a novel molybdenum-loaded catalyst for gas-phase photocatalytic hydrogen sulfide decomposition and its high performance: zero-out of 10 ppm of hydrogen sulfide. Moreover, the catalyst can be regenerated through photocatalytic reduction, keeping decomposing hydrogen sulfide to nearly odorless levels. The study provides a simple and sustainable photocatalytic process for removing low-concentration hydrogen sulfide, effectively preventing catalyst poisoning and enabling catalyst regeneration; thus, this suggests enhancing air quality and reducing health risks associated with this toxic gas in industrial and urban environments.