Upgrading V2O5-WO3/TiO2 deNOx Catalyst with TiO2-SiO2 Support Prepared from Ti-Bearing Blast Furnace Slag

The study is devoted to developing a rather high-efficiency NH3-SCR (selective catalytic reduction) catalyst for NOx removal using TiO2-SiO2 support made from blast furnace slag. Through adjusting hydrolytic pH value of TiOSO4 solution obtained from acidolysis of slag with 70 wt. % H2SO4, a series of TiO2-SiO2 mixed oxides was prepared to have different mass ratios of TiO2 to SiO2. The supports are further impregnated with V2O5 and WO3 to make the SCR catalysts for NOx removal. Characterizing the catalysts show that silica and unavoidable impurities in support prepared from slag were responsible for maintaining their mesoporous structure and the enhancements in the acidity and reducible form of active species on the catalyst surface, which thus rendered the catalysts to have higher NOx reduction capability than catalyst using commercial TiO2. Furthermore, the low-cost catalyst prepared from slag-based TiO2 support possesses good stability, and strong resistance to SO2 and H2O poisoning, which are beneficial to practical deNO(x) applications.