Cu- and Ce-promoted nano-heterostructures on vanadate catalysts for low-temperature NH3-SCR activity with improved SO2 and water resistance

Abstract

The objective of this study was to demonstrate a facile strategy for vanadate-based catalysts having high NOx conversion efficiency (similar to 96% @ 220 degrees C) and improved SO2 resistance by impregnating highly-dispersed CuO-CeO2 nano-heterostructures to V2O5-CeO2-WO3/TiO2 catalysts. The key design of catalysts was based on the maximization of interface chemistry towards synergetic effects of catalytic and redox reactions between Cu and Ce species. The impregnation of 0.1 wt% CuO-CeO2 possessed more surface acid sites and enhanced redox ability at low temperatures (180-220 degrees C). Based on Gibbs energy calculation and XPS results, thermodynamically favorable reaction of Cu2+ + Ce3+ -> Cu+ + Ce4+ made it a perfect candidate for an excellent redox system with V4+/V5+ charge imbalance proportion through electron migration at the adjacent interface. The strong redox interaction and facile electron transfer could also restrain the formation of surface sulfate species and showed an excellent SO2 and water tolerance.