氨催化还原NO_x中TiO₂负载过渡金属催化剂的催化行为  

Catalytic Performance of TiO2 Support of Transition Metal Catalysts for NO Reduction by Ammonia

作　　者：骆迪迪 潘华 蓝宁 陈郑辉 王晟康 吴谦 陈雪松[1] 王莉[1] 

机构地区：[1]浙江树人大学生物与环境工程学院,浙江杭州

出　　处：《化学工程与技术》2019年第3期272-281,共10页Hans Journal of Chemical Engineering and Technology

基　　金：浙江省自然科学基金资助项目(LY19E080023);浙江树人大学中青年学术团队项目(XKJ0516205);浙江树人大学科研启动基金资助项目(KXJ0517102);新苗人才计划(2018R421011);浙江树人大学高级别预研项目。

摘　　要：采用溶胶–凝胶法合成了TiO2催化剂载体,并通过浸渍法制备了一系列TiO2负载过渡金属脱硝催化剂。结合N2吸脱附、X射线衍射(XRD)和X射线光电子能谱(XPS)等手段,及催化活性评价研究了过渡金属/TiO2催化剂在氨选择催化还原NOx(NH3-SCR)中的催化行为。研究表明:过渡金属/TiO2催化剂活性为Mn/TiO2 >Fe/TiO2 >Cr/TiO2 >Co/TiO2。Mn/TiO2催化剂的脱硝活性最好,在250℃时最大脱硝效率达到93%。过渡金属/TiO2催化剂的脱硝活性与催化剂的比表面积和孔体积成正相关性。催化剂的活性组分是决定催化剂活性的主要因素,Mn/TiO2、Co/TiO2、Cr/TiO2和Fe/TiO2催化剂中活性组分分别为Mn4+、Co3O4、Cr3+和Fe3+。合适的氧活性物种比值(Olatt/Osurf = 4.7)和高活性的 Mn4+活性位使得Mn/TiO2催化剂具有高催化活性。Support TiO2 was synthesized by sol-gel method,and a series of transition metal/TiO2 catalysts were prepared by impregnation method.Combination of N2 adsorption-desorption,X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)and catalytic behavior of NO reduction with NH3 on transition metal/TiO2 catalysts were carried out by activity test.The results show that the activities of transition metal/TiO2 catalyst decrease in the order of Mn/TiO2>Fe/TiO2>Cr/TiO2>Co/TiO2.Mn/TiO2 catalyst exhibits the highest activity among various catalysts,and the maximum de-NOx efficiency can reach 93%at 250?C.The deNOx activity of transition metal/TiO2 catalysts is positively correlated with the specific surface area and pore volume of the catalysts.The active component of the catalysts is the determining factor for the activity of the catalysts.The active sites of Mn/TiO2,Co/TiO2,Cr/TiO2 and Fe/TiO2 catalysts are Mn4+,Co3O4,Cr3+and FeCr3+,respectively.A suitable ratio of oxygen active species(Olatt/Osurf=4.7)and active sites of Mn4+make the high activity of Mn/TiO2 catalyst.

关 键 词：二氧化钛 过渡金属 催化还原 氮氧化物 催化行为 

分 类 号：O64[理学—物理化学]