Catalytic combustion of vinyl chloride emission over a TiO2–MnOx catalyst. (1st September 2017) - Wan, Yiling
TiO2–MnOx catalyst samples with different Ti/(Ti + Mn) molar ratios (2:3, 3:4, 4:5, 5:6, 6:7 and 1) prepared by the citric acid (CA) sol-gel method were studied in the catalytic combustion of vinyl chloride (VC) emission. The effects of preparation conditions and operation parameters on the catalytic performance of TiO2–MnOx were investigated. The catalyst samples were characterised by N2 adsorption, X-ray diffraction (XRD) and H2-temperature programmed reduction (H2-TPR). In the catalytic combustion of VC over TiO2–MnOx, products containing HCl, CO2, and H2O were obtained and there were no by-products such as chlorohydrocarbons and chlorine. The TiO2–MnOx catalyst with the molar ratio of CA/Mn/Ti = 0.30:0.20:0.80 showed the best catalytic performance and had better operating flexibility over the ranges of gas hourly space velocity (GHSV) of 15000–100000 h–1 and VC concentration of 0.05–2.00%. The temperatures at 50% conversion (140 °C) and at 99% conversion (220 °C) were achieved at a VC concentration of 0.1% and GHSV of 15000 h–1. XRD characterisation indicated that only the characteristic diffraction peaks of TiO2 with the anatase structure appeared and no characteristic diffraction peaks of MnOx species appeared for the TiO2–MnOx catalyst. XRD and H2-TPR results indicated that Mn ions were incorporated into the TiO2 lattice to form a Ti–Mn–O solid solution, which enhanced the reactivity of active oxygen species on the catalyst surface and thereby promoted the catalyst activity.