Property influence and poisoning mechanism of HgCl2 on V2O5-WO3/TiO2 SCR-DeNOx catalysts

• V2O5-WO3/TiO2 SCR catalysts were deactivated with the addition of HgCl2.
• New NH3 adsorption sites were generated after HgCl2 addition.
• HgCl2-poisoning mechanism over V2O5-WO3/TiO2 SCR catalysts was proposed.

In this paper, HgCl2 was loaded by impregnation method to study its property influence and poisoning mechanism on V2O5-WO3/TiO2 SCR-DeNOx catalyst. For HgCl2-containing catalysts, deactivation was observed in simulated gas stream, and its catalytic activity declined with the increase of HgCl2 loadings. Brønsted acid sites (VOH) and VO bond were affected evidently by HgCl2, new NH3 adsorption site ClVOH was generated after HgCl2 addition. Interactions between HgCl2 and V2O5 resulted in the loss of SCR active sites, and –HgCl existed as the stable form on the bridge site. Finally, the probable schematic diagram of HgCl2 poisoning mechanism was also proposed.

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