Co负载量对Co/TiZrO_(4)催化CO_(2)氧化乙烷脱氢制乙烯反应性能的影响  

Effects of Co loading on the performance of Co/TiZrO_(4) catalysts for CO_(2) oxidative ethane dehydrogenation to ethylene

作　　者：刘欢 王樱 陈铭 叶代启 陈礼敏 LIU Huan;WANG Ying;CHEN Ming;YE Daiqi;CHEN Limin(School of Environment and Energy,South China University of Technology,Guangzhou 510006;National Engineering Laboratory for VOCs Pollution Control Technology and Equipment,Guangzhou 510006;Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control(SCUT),Guangzhou 510006)

机构地区：[1]华南理工大学环境与能源学院,广州510006 [2]挥发性有机物污染治理技术与装备国家工程实验室,广州510006 [3]广东省大气环境与污染控制重点实验室,广州510006

出　　处：《环境科学学报》2023年第2期433-446,共14页Acta Scientiae Circumstantiae

基　　金：广东省自然科学基金(No.2019A1515011849)。

摘　　要：Co基催化剂在低碳烷烃直接脱氢及氧化脱氢制烯烃方面表现出良好的应用潜力.为了探究Co物种的价态对CO_(2)氧化乙烷脱氢制乙烯的影响,以共沉淀法制备的TiZrO_(4)固溶体为载体,采用浸渍法制备了一系列X%Co/TiZrO_(4)(X=0.5、1、3、5和7.5)催化剂.结果表明,0.5%Co/TiZrO_(4)和1%Co/TiZrO_(4)催化剂的催化活性较差,但保持了相当高的C_(2)H_(4)选择性(>90%)和碳平衡(≈100%);3%Co/TiZrO_(4)催化剂在反应过程中表现出良好的C_(2)H_(6)和CO_(2)活化能力,在650℃、质量空速WHSV=9000 mL·g^(-1)·h^(-1)的反应条件下获得了约25%的乙烯收率;而5%Co/TiZrO_(4)和7.5%Co/TiZrO_(4)催化剂则在600℃及以上温度反应时乙烯选择性明显下降并伴随严重的积碳.SEM、XRD、Raman、UV-vis、XPS、H_(2)-TPR和in-situ Raman等研究表明,Co^(2+)-TiZrO_(4)存在金属-载体强相互作用,在反应中具有良好的C_(2)H_(4)选择性,适量的Co^(0)有助于CO_(2)和C_(2)H_(6)的活化,但大量聚集的Co^(0)会促进干重整和积碳反应,使催化剂严重积碳导致失活.Co-based catalysts exhibit great potential in direct dehydrogenation and oxidative dehydrogenation of light alkanes to alkenes.In order to elucidate the effects of the valence state of Co on the catalytic performance of CO_(2)oxidative ethane dehydrogenation to ethylene,a series of X%Co/TiZrO_(4)(X=0.5,1,3,5 and 7.5)catalysts were prepared by impregnation using the TiZrO_(4)solid solution obtained by co-precipitation as support.Among them,0.5%Co/TiZrO_(4)and 1%Co/TiZrO_(4)showed low activity but considerable C_(2)H_(4)selectivity(>90%)and carbon balance(≈100%);3%Co/TiZrO_(4)appeared excellent C_(2)H_(6)and CO_(2)conversion during the whole process and obtained about 25%C_(2)H_(4)yield at 650℃and WHSV of 9000mL·g^(-1)·h^(-1).However,5%Co/TiZrO_(4)and 7.5%Co/TiZrO_(4)exhibited a significant decrease in ethylene selectivity and severe coke deposition when the reaction temperature was higher than 600℃.SEM,XRD,Raman,UV-vis,XPS,H_(2)-TPR and in-situ Raman characterizations indicate that Co^(2+)-TiZrO_(4)possesses high C_(2)H_(4)selectivity due to the strong metal-support interactions.Moderate amount of Co^(0)contributes to the activation of CO_(2)and C_(2)H_(6),while the aggregated bulk Co^(0)nanoparticles promote the dry-reforming reaction and coke deposition,resulting in catalyst deactivation.

关 键 词：CO_(2) 乙烷氧化脱氢 乙烯 Co基催化剂 金属-载体相互作用 

分 类 号：X511[环境科学与工程—环境工程]