钾对催化剂选择性催化还原氮氧化物的性能影响特性研究  

Effect of potassium on the selective reduction of NO by NH_3 on V_2O_5 catalysts

作　　者：胡石磊[1] 叶代启[1] 

机构地区：[1]华南理工大学环境科学与工程学院,广东广州510006

出　　处：《环境污染与防治》2008年第7期43-46,共4页Environmental Pollution & Control

摘　　要：试验就碱金属钾对两种催化剂V2O5/TiO2(VT)和V2O5/TiO2-SiO2(VTS)选择性催化还原(SCR)氮氧化物的性能影响作了相关研究,运用BET比表面积、X射线衍射(XRD)谱图、傅立叶变换透射红外光谱(FT-IR)谱图对催化剂进行表征。结果表明,试验制备的TiO2-SiO2比表面积达360m2/g,催化剂表面活性组分高度分散;NH3吸附红外谱图显示催化剂VTS具有丰富的表面酸;催化剂抗钾毒害试验发现,钾易与B酸位结合从而降低对NH3的吸附量和吸附活性,催化剂VTS具有明显优于VT的抗钾毒害性能,归因于部分钾优先与VTS表面酸结合,从而降低对钒活性物种的毒害。此外,失活程度跟钾/钒(K/V)的摩尔比密切相关。催化活性随反应进行不断降低,且24h内难以恢复到原有水平。Abstract： The effectiveness of V2O5/TiO2 （VT） and V2O5/TiO2-SiO2 （VTS） in selective catalytic reduction （SCR） of NO by NH3 was investigated. The TiO2 and TiO2-SiO2 based catalysts were prepared and then characterized by BET, XRD and FT-IR. The base TiO2-SiO2 had a much higher surface area relative to base TiO2 （360 m^2/g vs. 42 m2/g） ; VOx loading （3% by weight） resulted in uniform dispersion of the catalyst and a small reduction in the specific surface areas. The presence of potassium reduced surface acidity resulting in a lower adsorptive capacity for NH3. VTS exhibited much better resistance to potassium poisoning relative to VT, due to its much higher specific surface area and also the reaction of the adsorbed potassium with the acidic sites of its surface. The extent of catalyst deactivation was positively correlated with the molar K/V ratio. The adverse effects of poisoned catalysts continued in the next 24 h of reaction.

关 键 词：选择性催化还原 钾毒害 催化剂失活 B酸 

分 类 号：X701[环境科学与工程—环境工程] O643.36[理学—物理化学]