Abstract: A series of honeycomb V₂O₅-MoO₃/TiO₂  catalysts was prepared by extrusion molding. The effects of vanadium loading and molybdenum loading on the denitration activity of the catalysts and the performance of the catalysts against sulfur and alkali metal poisoning were tested. The physicochemical properties of fresh catalyst and sodium poisoned catalyst were analyzed by means of XRD, BET, SEM, H₂-TPR and XPS techniques. The results showed that when the vanadium loading (w) was in the range of 1.5%-2.5%, the denitration activity of the catalyst increased with the increase of vanadium loading. When the vanadium loading (w) was 1.5% and the molybdenum loading (w) was 4.0%, the catalyst had the best denitration performance. The poisoning effect of SO₂ on the V₂O₅-MoO₃/TiO₂ catalyst was reversible and could be recovered by heat treatment. When the Na₂O loading (w) was 2.0%, the catalyst was severely deactivated because the sodium salt agglomerated on the surface of the catalyst to form irregular white particles, covering the active site, resulting in a reduction of the catalyst surface area and poor redox performance. In addition, Na doping would affect the chemical state and surface composition of the active elements on the catalyst, reducing the ratio of V⁵⁺ and chemically adsorbed oxygen (O_α).

Key words: V2O5-MoO3/TiO2 catalyst, denitration, selective catalytic reduction, sodium poisoning