Photocatalytic and catalytic materials for the oxidation of hydrogen sulfide in air purification systems
Abstract
This research explores the development and characterization of advanced functional materials for the photonic and photocatalytic purification of atmospheric air from toxic hydrogen sulfide (H<sub>2</sub>S). While adsorption methods are common, this study focuses on the catalytic and photocatalytic oxidation of H₂S into elemental sulfur and water, a process enhanced by specific light interactions. We investigated the activity and selectivity of various metal oxide semiconductors, including WO<sub>3</sub>, CuO, Fe<sub>2</sub>O<sub>3</sub>, and MnO<sub>2</sub>, in the oxidative decomposition of H<sub>2</sub>S. The microstructure and morphology of the synthesized nanocrystalline powders were analyzed using transmission electron microscopy (TEM) to correlate their photonic properties with performance. The photocatalytic decomposition kinetics of H<sub>2</sub>S under UV irradiation were determined, revealing a first-order reaction with a rate constant of 0.1609 h<sup>-1</sup>. Furthermore, the study identifies an optimal binary composite, 5% CuO + 95% WO<sub>3</sub>, which demonstrates exceptional catalytic activity and selectivity for H<sub>2</sub>S oxidation at 325–400 °C, achieving near-complete conversion (98-100%) while minimizing the oxidation of co-existing gases like CH<sub>4</sub>, CO, and H<sub>2</sub>. This synergy between copper and tungsten oxides presents a promising material system for designing efficient air purification technologies. The findings highlight the critical role of material chemistry in tailoring photonic and catalytic properties for environmental remediation applications, specifically for the selective detection and removal of hazardous gases using light-enhanced processes.