NOx reduction over catalysts with inborn resistance to multipoisons

Abstract

Selective catalytic reduction (SCR) of NH3 is a widely used technology for eliminating NOx, but alkali metals, heavy metals, SO2, and other flue gas contaminants can drastically reduce the service life of catalysts and increase the cost of environmental protection. This study demonstrates that the TiOSO4/CeO2 catalyst exhibits natural resistance to multipoisons for NOx reduction. Despite being poisoned with 1 wt% K2O and 3 wt% PbO, the catalyst retained a NOx conversion rate of over 95% across a wide temperature range of 225–450 °C and showed excellent tolerance to SO2. The catalyst's interfacial structure is composed of cross-linked TiO6-SO4-Ce-O units. When K&Pb were deposited on the TiOSO4/CeO2 catalyst, the SO42- ions distributed on the catalyst surface preferentially combined with K&Pb to protect the Ce active sites. Additionally, the cross-linked TiO6 layer structure on the catalyst surface effectively blocked the adsorption of SO2. This anti-poison strategy enhances NOx reduction and resistance by modifying intrinsic active sites, rather than constructing additional sacrificial sites traditionally. These findings have significant implications for the development of effective NOx reduction catalysts with excellent resistance to multipoisons for practical applications.