V2O5-MoO3/TiO2催化剂脱硝性能的研究

通过挤压成型法制备了一系列蜂窝状V₂O₅-MoO₃/TiO₂催化剂。研究了钒、钼负载量对催化剂脱硝活性的影响，测试了催化剂抗硫和抗碱金属钠中毒的性能。采用X射线衍射、N₂吸附-脱附、扫描电子显微镜等表征手段，对新鲜催化剂和钠中毒催化剂的物理和化学性质进行分析。结果表明：当钒负载量（w）为1.5％～2.5％时，催化剂的脱硝性能随钒负载量的增加而提高；当钒负载量（w）为1.5%、钼负载量（w）为4.0％时，催化剂的脱硝性能最优；SO₂对V₂O₅-MoO₃/TiO₂催化剂的中毒作用是可逆的，可以通过热处理来恢复；当Na₂O负载量（w）为2.0％时，催化剂失活严重，这主要是由于钠盐在催化剂表面附聚而形成不规则的白色颗粒，覆盖了活性位点，导致催化剂的表面积减小，氧化还原性变差。同时，Na掺杂会影响催化剂中元素的化学状态和表面组成，降低V⁵⁺与化学吸附的O_α的比例。

RESEARCH OF DENITRATION PERFORMANCE OF V2O5-MoO3/TiO2 CATALYST

A series of honeycomb V₂O₅-MoO₃/TiO₂catalysts 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/TiO₂catalyst 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).