Insight into enhancing the resistance to K, HO and SO over MnVO supported on TiO in NH-SCR denitration reaction.

Alkali metal poisoning remains an essential issue causing the deactivation of vanadate-based catalysts for selective catalytic reduction (SCR) catalysts of NO with NH. In this paper, MnVO was loaded onto TiO (mwt%MnVO/TiO, m = 3, 5, 7) to improve the low-temperature activity and resistance to K poisoning. The activity tests demonstrated that 5 wt%MnVO/TiO catalyst was remarkably resistance to SO and HO, sustaining a NO conversion of over 90 % in the temperature range of 200-340 °C even after K poisoning. The mechanism of 5 wt%MnVO/TiO resistance to K was studied using a variety of characterizations. The findings showed that K tends to interact with TiO, preventing it from damaging the surface structure of MnVO and Mn active sites and therefore sustaining the redox cycle in SCR reaction. Furthermore, loading onto TiO enhanced the specific surface area and acidity of 5 wt%MnVO/TiO catalyst in comparison to MnVO, effectively minimizing the adverse impact of K poisoning on acidity and specific surface area while also assuring NH adsorption and activation. This study introduces a novel method to fabricate catalysts with superior alkali metal resistance.