Study of the Effect of Bi and Ce Doping on the Performance of the VWTi Catalyst for Reduction of Nitrogen Oxides

Abstract

Ce-doped V₂O₅-WO₃/TiO₂ (CeVWTi) and its subsequent modifications have been recognized as effective catalysts for the selective catalytic reduction of NO. Herein, CeVWTi catalysts doped with varying amounts of bismuth sulfate (Bi₂(SO₄)₃) were synthesized and evaluated for their activity and alkali resistance. These catalysts were characterized using XPS, BET, SEM, H₂-TPR, NH₃-TPD, and XRD techniques. The optimal doping level of Bi₂(SO₄)₃ was 1 wt.%. The NO conversion rate of the catalyst co-doped with Ce and Bi was 71.6% under the reaction conditions of 300 °C, gas hour space velocity (GHSV) = 200,000 h⁻¹ with a gas composition of 550 ppm NO, 550 ppm NH₃, 5.6% O₂, and N₂ as the balance. The NO conversion efficiency of the Bi_0.01CeVWTi catalyst was maintained at 90.7% after the addition of 1 wt.% KCl poisoning under the reaction conditions of 350 °C, GHSV = 200,000 h⁻¹, 550 ppm NO, 550 ppm NH₃, 5.6% O₂, and N₂ as the balance. Characterization showed that, despite the reduction in the specific surface area of the catalyst and some acidic sites due to Bi doping, the redox performance of Bi_0.01CeVWTi was significantly enhanced. The excellent redox performance was maintained even after KCl poisoning.