Enhanced SO2-Resistance Ability of Ce-Modified TiO2-Wrapped V2O5 Catalyst

Abstract

SO₂-resistance ability is critical for a catalyst since SO₂ usually coexists in polluted gas and results in catalyst deactivation. In this work, structural design and Ce modification methods are utilized to synthesize a Ce-modified TiO₂-wrapped V₂O₅ catalyst, and its performance is verified in the selective catalytic reduction of nitrogen oxide (SCR). As a result, the wrapped structure (Ti/V_S) and Ce modification (CeTi/V_S) not only increase the conversion but also enhance the SO₂-resistance ability. Under the same V amount and catalysis conditions, Ti/V_S reaches a removal rate of 60% at 250 °C, which is higher than that (55%) of the typical V-supported TiO₂ (V/Ti). The conversion of CeTi/V_S is further increased to 72%. After SO₂ deactivation, conversions follow the order of 25% (V/Ti) < 38% (Ti/V_S) < 52% (CeTi/V_S). In addition, SO₂ deactivation is easier to reduce in the two wrapped catalysts under thermal regeneration. After detailed characterizations of surface elements and SCR intermediates, the mechanism for the enhanced SO₂-resistance ability is revealed. In brief, SO₂-derived species on Ti/V_S are replaceable by nitrogen oxide, and Ce-combined SO₂ in CeTi/V_S functions as new sites for SCR. Besides, the two wrapped catalysts have larger specific surface areas than V/Ti. The main result of this work is devoted to understanding the structure–function relationship, which is also in favor of promoting catalyst application.