A tale of two pollutants: The mutual promotion mechanism of synergistic catalytic elimination of Hg0 and chlorobenzene on V2O5-WO3/ TiO2 catalyst

The co-benefit of Hg0 or chlorinated volatile organic compounds (CVOCs) oxidation can be achieved by using vanadium-based catalysts in the selective catalytic reduction (SCR) unit. However, there is no research on the synergistic catalytic elimination of Hg0 and chlorobenzene (CB) in vanadium-based catalysts. Herein, the reaction mechanism of catalytic elimination of Hg0 and CB on vanadium-based catalysts was systematically analyzed and discussed for the first time. It is surprisingly observed that there is a synergistic effect between chlorobenzene catalytic oxidation (CBCO) and Hg0 oxidation. That is, CB could enhance Hg0 oxidation by providing active chlorine species, while the presence of Hg0 could also promote CBCO and reduce the formation of polychlorinated byproducts due to the consumption of chlorine species in the Hg0 oxidation reaction according to Le Chatelier's principle. This synergistic effect was conducive to maintaining the physical structure and electronic properties of the catalyst and weakening the deposition of elements chlorine and mercury on the catalyst surface, promoting the re-exposure of active centers. This work provides unique insights for synergistic catalytic elimination of Hg0 and CB, and is expected to guide the prospective application on vanadium-based catalysts for multipollutant control.