宽工作温度烟气脱硝催化剂制备及反应机理研究

被引：18

作者：

郭凤 ^{[1
,2
]}

余剑 ^{[2
]}

牟洋 ^{[2
]}

初茉 ^{[1
]}

许光文 ^{[2
]}

机构：

[1] 中国矿业大学(北京)化学与环境工程学院

[2] 中国科学院过程工程研究所多相复杂系统国家重点实验室

来源：

燃料化学学报 | 2014年 / 42卷 / 01期

关键词：

选择性催化还原; 脱硝; 原位红外光谱; NH3吸附; 反应机理;

D O I：

暂无

中图分类号：

TQ426 [催化剂（触媒）];

学科分类号：

080502 ; 081705 ;

摘要：

以溶胶-凝胶法制备介孔TiO2载体,采用分步浸渍法制备了V2O5-WO3/TiO2催化剂,借助BET、NH3-TPD、H2-TPR、SEM、活性评价、In-situ FT-IR等手段,考察了催化剂的结构、酸性、还原性、脱硝活性及反应机理等。介孔TiO2载体比表面积为158.6 m2/g,制成催化剂后比表面积略有降低,约为136.7 m2/g。针对模拟烟气在φNH3/φNO=0.8的条件下测试催化剂的脱硝活性温度窗口为250～400℃,脱硝转化率达到80%。NH3-TPD和H2-TPR表征结果表明,催化剂在活性温度范围内具有典型的表面酸性位,载体TiO2与V2O5之间存在的相互作用使得V2O5还原温度降低。利用In-situ FT-IR研究NH3和NO在V2O5-WO3/TiO2催化剂表面吸附和氧化的反应过程发现,NH3可同时吸附在L酸位和B酸位,NH3在活性位上氧化脱氢形成NH2物种是SCR脱硝反应的控制步骤。研究NO+O2+NH3反应时发现,吸附NH3的催化剂引入NO和O2后,共价吸附的NH3首先消失。选择性催化还原反应发生在吸附态NH3和气态或弱吸附态的NO之间,该反应遵从Eley-Rideal反应机理。

引用

页码：101 / 109

页数：9

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