CuO_(x)/SiO_(2)催化剂化学态调控及低温脱硝性能研究  

Chemical States Regulation and Performance on Selective Catalytic Reduction of NO_(x) with NH_(3) at Low-Temperature over CuO_(x)/SiO_(2) Catalysts

作　　者：张柏林 杨泽宇[1] 黄鸣天 张生杨 刘波 张深根 Zhang Bolin;Yang Zeyu;Huang Mingtian;Zhang Shengyang;Liu Bo;Zhang Shengen(Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China;Shunde Innovation School,University of Science and Technology Beijing,Foshan 528399,China)

机构地区：[1]北京科技大学新材料技术研究院,北京100083 [2]北京科技大学顺德创新学院,广东佛山528399

出　　处：《稀有金属》2024年第11期1519-1528,共10页Chinese Journal of Rare Metals

基　　金：国家自然科学基金青年基金项目(52204414);国家节能低碳材料生产应用示范平台项目(TC220H06N);佛山市人民政府科技创新专项资金项目(BK22BE001);中央高校基本科研业务费专项资金项目(FRF-IDRY-20-005)资助

摘　　要：选择性催化还原(SCR)技术以NH_(3)还原氮氧化物(NO_(x))生成N2和H2O,是实现NO_(x)超低排放的主流技术。现有SCR脱硝催化剂一般只适用于200℃以上的烟气脱硝,研发适用200℃以下的低温脱硝催化剂具有显著的节能降碳效益。采用溶胶-凝胶法制备CuO_(x)/SiO_(2)催化剂,通过控制焙烧气氛调节CuO_(x)的化学态,表明随着焙烧气氛中还原性的增强,CuO_(x)/SiO_(2)催化剂中结晶析出的Cu_(2)O物相增多,BET比表面积、孔容、Cu^(2+)/Cu比例逐步下降;在50%(体积分数)的O_(2)气氛中焙烧的CuO_(x)/SiO_(2)-O催化剂表面Cu^(2+)含量高,Cu^(2+)/Cu达到了87.5%(原子分数),在100~125℃的低温区间表现出较高活性;在1.0%(体积分数)的NH_(3)气氛中焙烧的CuO_(x)/SiO_(2)-1.0A催化剂表面则Cu^(+)含量高,Cu^(+)/Cu达到了57.0%(原子分数),在150~200℃的高温区间表现出较高活性,在200℃时NO转化率达到了90.2%;分析表明在低温区间Cu^(2+)发挥着主要作用,Cu^(2+)↔Cu^(+)的循环转变为主要的催化循环过程;在高温区间则可能Cu^(+)发挥着主要作用,而Cu^(2+)可能起次要作用,Cu^(2+)与Cu^(+)组分相互协调,可能同时存在着Cu^(2+)↔Cu^(+)和Cu^(+)↔Cu^(0)的催化循环过程。Selective catalytic reduction(SCR)technology is the primary approach to achieving ultra-low emissions of nitrogen oxides(NO_(x)),using NH_(3) as a reducing agent to convert NO_(x) into N2 and H2O.However,the existing V2O5-WO_(3)(MoO_(3))/TiO_(2) catalysts generally works at high-temperatures typically ranging from 300 to 420℃,which fails to meet the requirement at low-temperature(100~200℃)for numerous non-coal power industries.The development of novel catalysts meeting the deNO_(x) at low-temperature have significant energy consumption and cost advantages due to being free from the reheating of flue gas.In this study,CuO_(x)/SiO_(2) catalysts were prepared using the sol-gel method,with the calcination atmosphere controlling to 50%O_(2)(volume fraction),standard N2,0.1%NH_(3)(volume fraction),0.4%NH_(3)(volume fraction),and 1.0%NH_(3)(volume fraction),resulting in samples denoted as CuO_(x)/SiO_(2)-O,CuO_(x)/SiO_(2)-N,CuO_(x)/SiO_(2)-0.1A,CuO_(x)/SiO_(2)-0.4A and CuO_(x)/SiO_(2)-1.0A,respectively.The phase composition was analyzed using X-ray diffraction(XRD),the morphology was observed through scanning electron microscopy(SEM),the specific surface area and pore structures were analyzed using a fully automated surface area and porosity analyzer(Micromeritics APSP 2460)via N2 adsorption-desorption tests,the surface elemental chemical states were analyzed using X-ray photoelectron spectroscopy(XPS),and the temperature-programmed desorption(NH_(3)-TPD)and temperature-programmed reduction(H2-TPR)tests were conducted using a fully automated temperature-programmed chemisorption analyzer(Micromeritics Autochem II 2920).XRD results indicated that the catalysts were primarily composed of amorphous structures,with the presence of Cu_(2)O in CuO_(x)/SiO_(2)-1.0A,CuO_(x)/SiO_(2)-0.4A,CuO_(x)/SiO_(2)-0.1A and CuO_(x)/SiO_(2)-N catalysts,evidenced by gradually decreasing diffraction peak intensities of Cu_(2)O.Notably,CuO_(x)/SiO_(2)-O catalyst calcined in 50%O_(2)(volume fraction)atmosphere exhibited no Cu_(2)O diffraction

关 键 词：低温脱硝 选择性催化还原(SCR) 铜基催化剂 化学态 氧化还原 

分 类 号：TK91[动力工程及工程热物理]