Short communicationAn efficient novel regeneration method for Ca-poisoning V2O5-WO3/TiO2 catalyst

- Deactivation mechanism of CaO on V2O5-WO3/TiO2 catalysts are studied.
- CaO can passivate bulk tungsten species and surface acid sites of fresh catalyst.
- CaWO4 formation occurs after the high content of CaO is introduced.
- HEDP regeneration shows excellent removal rate of CaO but low V2O5 loss.

Ca poisoning and regeneration on V2O5-WO3/TiO2 catalysts for selective catalytic reduction of NOx was investigated based on the changes of activity, structure, reducibility, acidity and reaction details. It is found that high contents of CaO can lead to CaWO4 formation and thus passivate bulk tungsten species and surface acid sites of fresh catalyst. Additionally, reactable surface oxygen species and reducibility are also greatly suppressed by CaO species. However, unlike previous regeneration method, HEDP showed exclusive and excellent removal rate of CaO without large active ingredients loss, which had a better prospect of industrial application.