Selective catalytic reduction (SCR) over V₂O₅/TiO₂-based catalysts is the most efficient technology to remove nitrogen oxides from stationary sources, where H₂S coexists with NO_x under variable combustion conditions. For the first time, the poisoning effect of H₂S was observed to be almost six-fold that of SO₂. Catalyst deactivation under SO₂ was mainly caused by ammonium bisulfate while sulfates, especially polymeric sulfate, were the main contributors to H₂S poisoning. Theoretical calculations showed that the generation of sulfates was much more energetically favorable under H₂S than under SO₂, resulting in massive deposition of sulfates and serious damage to vanadyl (VO). Polymeric sulfate could inhibit the charge transfer between the occupied and unoccupied orbitals of VO and suppress NH₃ activation, thereby significantly restraining SCR activity. Furthermore, unstable sulfur species were shown to be responsible for the temporary deactivation during H₂S poisoning. This work provides crucial information for solving catalyst deactivation.

_{基于 V 2} O ₅ /TiO ₂的催化剂的选择性催化还原 (SCR)是从固定来源去除氮氧化物的最有效技术，其中 H ₂ S在可变燃烧条件下与 NO _x共存。首次观察到 H _{2 S 的中毒作用几乎是 SO 2}的六倍。催化剂在SO _{2下的失活主要由硫酸氢铵引起，而硫酸盐，尤其是聚合硫酸盐，是H 2} S中毒的主要原因。_{理论计算表明，在 H 2}下，硫酸盐的生成在能量上更为有利S 低于 SO ₂，​​导致硫酸盐大量沉积，严重破坏氧钒（VO ）。聚合硫酸盐可以抑制V O占据和未占据轨道之间的电荷转移并抑制NH ₃活化，从而显着抑制SCR活性。此外，不稳定的硫物质被证明是造成 H ₂ S 中毒期间暂时失活的原因。这项工作为解决催化剂失活问题提供了重要信息。