Effects of mercury oxidation on V2O5–WO3/TiO2 catalyst properties in NH3-SCR process

• Mercury oxidized over V2O5–WO3/TiO2 to prepare mercury exposed catalyst.
• NO conversion of mercury exposed catalyst decreases compared with the fresh one.
• XPS confirmed the transformation of V5 + species into V4 + species.
• Lattice oxygen on the surface of catalyst was consumed after mercury oxidation.
• Results indicated the competitive reaction on the catalyst surface.

The effects of mercury oxidation on V2O5–WO3/TiO2 SCR catalyst's physical and chemical properties have been investigated. Both fresh catalyst and mercury exposed catalyst have been examined by BET, XRD, XPS and catalytic activity measurements. Mercury oxidation promoted the V5 + species transforming to the V4 + species and consumed the lattice oxygen on the surface of catalyst. In addition, the NO conversion of mercury exposed catalyst decreased in the range of 200 °C to 300 °C. It suggested a competitive relationship between gaseous NH3 and adsorbed mercury on the catalyst surface in that temperature range.

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