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

The objective of this study was to demonstrate a facile strategy for vanadate-based catalysts having high NOx conversion efficiency (∼96% @ 220 °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 °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.