Design Strategies for Development of SCR Catalyst: Improvement of Alkali Poisoning Resistance and Novel Regeneration Method

Based on the ideas of the additives modification and regeneration method update, two different strategies were designed to deal with the traditional SCR catalyst poisoned by alkali metals. First, ceria doping on the V2O5-WO3/TiO2 catalyst could promote the SCR performance even reducing the V loading, which resulted in the enhancement of the catalyst's alkali poisoning resistance. Then, a novel method, electrophoresis treatment, was employed to regenerate the alkali poisoned V2O5-WO3/TiO2 catalyst. This novel technique could dramatically enhance the SCR activities of the alkali poisoned catalysts by removing approximately 95% K or Na ions from the catalyst and showed less hazardous to the environment. Finally, the deactivation mechanisms by the alkali metals were extensively studied by employing both the experimental and DFT theoretical approaches. Alkali atom mainly influences the active site V species rather than W oxides. The decrease of catalyst surface acidity might directly reduce the catalytic activity, while the reducibility of catalysts could be another important factor.