摘要
本文采用浸渍法制备了Nb改性的V_(2)O_(5)-WO_(3)/TiO_(2)催化剂,研究了脱硝反应中Nb负载量对催化剂SO_(2)氧化活性的影响。结果表明,在350℃下,Nb_(2)O_(5)负载量为2%的Nb_(2)O_(5)-V_(2)O_(5)-WO_(3)/TiO_(2)催化剂上的SO_(2)氧化率最低(0.6%),而同时NO_(x)的转化率仍能达到95%。采用TGA、氮吸附、XRD、H_(2)-TPR、CO_(2)-TPD、XPS和in-situ DRIFTS等对催化剂进行了表征分析,结果显示,Nb改性后V_(2)O_(5)-WO_(3)/TiO_(2)催化剂的晶体结构没有发生明显改变,但是其比表面积小幅度下降,有助于减少对SO_(2)的吸附;同时,改性后催化剂表面的吸附氧含量下降,氧化还原性能也稍微减弱,这有利于降低其对SO_(2)的氧化活性。in-situ DRIFTS结果表明,Nb改性后的Nb-V_(2)O_(5)-WO_(3)/TiO_(2)催化剂反应过程中表面中间产物VOSO4的含量明显下降,从而减少了SO_(3)的生成量。
A series of Nb-modified V_(2)O_(5)-WO_(3)/TiO_(2)catalysts were prepared by the impregnation method and the effect of Nb loading on their SO_(2)oxidation activity during the selective catalytic reduction of NO_(x)was investigated.The results indicate that the Nb_(2)O_(5)-V_(2)O_(5)-WO_(3)/TiO_(2)catalyst with a Nb_(2)O_(5)loading of 2%exhibits the lowest SO_(2)conversion of 0.6%for oxidation at 350°C,whereas the conversion of NO_(x)is still above 95%.The catalysts were characterized by TGA,BET,XRD,H_(2)-TPR,CO_(2)-TPD,XPS and in-situ DRIFTS.The results illustrate that the influence of Nb modification on the crystal structure of V_(2)O_(5)-WO_(3)/TiO_(2)catalyst is rather insignificant;however,the surface area of the Nb_(2)O_(5)-V_(2)O_(5)-WO_(3)/TiO_(2)catalyst decreases slightly after the modification with Nb,conducing to a decrease of SO_(2)adsorption on the catalyst.Meanwhile,the content of oxygen adsorbed on the catalyst surface decreases considerably upon the Nb modification,suggesting a weakened redox performance,which is beneficial to reducing the oxidation of SO_(2).The in-situ DRIFTS results illustrate that the content of the intermediate VOSO4 product on the catalyst surface decreases over the Nb-modified Nb_(2)O_(5)-V_(2)O_(5)-WO_(3)/TiO_(2)catalyst,leading to a decrease of SO_(3)production.
作者
王博
边瑶
封硕
王少奇
沈伯雄
WANG Bo;BIAN Yao;FENG Shuo;WANG Shao-qi;SHEN Bo-xiong(College of Energy and Environmental Engineering,Hebei University of Technology,Key Laboratory of Clean Energy Utilization and Pollutant Control in Tianjin,Tianjin 300401,China;College of chemical engineering,Hebei University of Technology,Tianjin 300401,China)
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2022年第4期503-512,共10页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金(U20A20302)
天津市重点研发项目(19ZXZSN00050,19ZXSZSN00070)
河北省重点研发项目(20373701D)
河北省重大科技攻关项目(21283701Z)资助。
