含铈钒基SCR催化剂脱硝性能及SO_2失活机理研究  

Activity and SO_2 deactivation mechanism of vanadium series catalyst containing cerium

作　　者：杨剑[1] 林凡[1] 陈奎[1] 孔明[1] 赵冬[1] 孟飞[1] 

机构地区：[1]重庆大学材料科学与工程学院重庆市能源环境工程研究中心,重庆400044

出　　处：《燃料化学学报》2016年第11期1394-1400,共7页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(51204220;51274263);重庆市自然科学基金(cstc2013jjB0035)资助~~

摘　　要：掺杂Ce到V_2O_5-WO_3/TiO_2催化剂中,并研究其NH_3-SCR脱硝性能及SO_2失活机理。结果表明,V_1W_5Ce_6 Ti表现出更好的脱硝活性。采用XRD、BET、FT-IR、TG-DSC、XPS等手段表征分析Ce对催化剂性能的影响,并提出V_1W_5Ce_6Ti硫失活机理。结果表明,Ce、V、W都能在催化剂中很好的分散,当Ce的掺杂量达到8%时,有明显的CeO_2特征峰出现。在250℃时,V_1W_5Ti(U)表面会有NH4HSO4和(NH_4)_2SO_4生成。掺杂Ce后,V1W5Ce6Ti催化剂的Brnste酸位和表面化学吸附氧都增加。Ce与烟气中的SO_2和H_2O结合生成硫酸铈盐,从而抑制硫酸铵盐的生成。同时也阻断了Ce^(3+)与Ce^(4+)氧化还原循环,破坏V-O-Ce结构,造成催化剂活性下降。The promotion effect of Ce modification on V_2O_5-WO_3/TiO_2 for the selective catalytic reduction(SCR) of NOx with NH_3 and the SO_2 deactivation mechanism were investigated. Compared with V_1W_5 Ti catalyst,the advantage of V1W5Ce6 Ti catalyst shows a good catalytic activity. These catalysts were investigated by means of XRD,BET,FT-IR,TG-DSC and XPS. The results demonstrate that the active components of V and W are well-dispersed,while a small cluster of cubic CeO_2 appears over the V1W5Ce8 Ti catalyst. The sulfation of V1W5 Ti under reactive conditions can generate NH_4HSO_4 and(NH_4)_2SO_4 at 250 ℃. The Ce additive to V1W5 Ti could provide stronger Brnsted acid sites and more chemisorbed oxygen. The deposited ammonium sulfate on V_1W_5Ce_6 Ti catalyst is much smaller than that on V1W5 Ti because the cerium sulfates species on the surface of V_1W_5Ce_6 Ti is formed and the deposition of ammonium sulfate is inhibited,which can disrupt the redox cycle between Ce^(3+) and Ce^(4+) and break the V-O-Ce structure,causing the deactivation of V_1W_5Ce_6 Ti catalyst.

关 键 词：选择性催化还原 V2O5-WO3/TIO2 铈掺杂 SO:失活 

分 类 号：X703.5[环境科学与工程—环境工程]