Oxidation of CO and slipped NH3 over a WS2-Loaded Pt/TiO2 catalyst with an extended reaction temperature range

The recent tightening of emission regulations aims to reduce the release of CO and slipped NH3 with industrial flue gas, necessitating the development of improved CO and NH3 oxidation catalysts, as conventional Pt catalysts are easily poisoned by the SO2 present in flue gas. In particular, the reaction temperature range of existing Pt/TiO2 catalysts and their resistance to sulfur poisoning can be improved by enhancing Pt dispersion through modification with WS2. This study examined the ability of WS2-doped Pt/TiO2 catalysts prepared using different WS2 loadings (3.6 and 5 wt%) at various calcination temperatures (300, 400, and 500 °C) to promote the oxidation of CO and NH3 in the absence and presence of SO2. The partial conversion of WS2 to WO3 at high calcination temperatures is found to be of key importance for securing high catalyst performance. The optimal catalyst exhibits high oxidation activity and sulfur resistance at low temperatures, achieving CO and NH3 oxidation efficiencies of ≥85% and 100%, respectively, at an SO2 content of 100 ppm and 280 °C.