前驱体调控铬系催化剂活性位点并用于丙烷非氧化脱氢研究  

Control of active sites of chromium-based catalysts by adjusting precursor and application in non-oxidative dehydrogenation of propane

作　　者：张哲玮 杨双 黄子君 何德东 罗永明[1,3,4] 陆继长 ZHANG Zhe-wei;YANG Shuang;HUANG Zi-jun;HE De-dong;LUO Yong-ming;LU Ji-chang(Faculty of Environmental Science and Engineering,Kunming University of Science and Technology,Kunming 650500,China;Faculty of Chemical Engineering,Kunming University of Science and Technology,Kunming 650500,China;Yunnan Provincial Innovation Team for Pollution Control and Reutilization of Volatile Organic Compounds,Kunming 650500,China;The Higher Educational Key Laboratory for Controlling Odorous Volatile Organic Compounds of Yunnan Province,Kunming 650500,China)

机构地区：[1]昆明理工大学环境科学与工程学院,云南昆明650500 [2]昆明理工大学化学工程学院,云南昆明650500 [3]昆明理工大学挥发性有机物污染防治与资源化省创新团队,云南昆明650500 [4]云南省高校恶臭挥发性有机物控制重点实验室,云南昆明650500

出　　处：《现代化工》2021年第3期125-129,共5页Modern Chemical Industry

基　　金：国家自然科学基金(21667016,21666013,21966018);云南省教育厅科学研究基金项目(2020J0060,21666013)。

摘　　要：针对目前丙烷非氧化脱氢中铬系催化剂活性位点存在的问题,通过调控不同铬基前驱体负载在MCM-41上来建立活性位点与催化性能之间的构效关系。利用XPS、H_(2)-TPR、XRD、UV、H_(2)-TPR等表征手段对催化剂的价态、活性物种的存在形式等进行表征。结果表明,制备的3种铬基催化剂都有单体的Cr(Ⅵ)、聚合的Cr(Ⅵ)以及块状的Cr_(2)O_(3)。Cr/MCM-41(H8CrN_(2)O_(4))产生更多Cr(Ⅵ);催化剂所形成的单体的Cr(Ⅵ)促进活性的提升;与之相反,聚合的Cr(Ⅵ)和块状的Cr_(2)O_(3)阻碍催化剂的性能。单体的Cr(Ⅵ)在遇到丙烷迅速被还原成配位不饱和的Cr^(3+)、Cr^(2+),进一步说明单体的Cr(Ⅵ)是铬系催化剂应用于丙烷非氧化脱氢的活性位点的前体。In view of the controversial problem of the active sites of chromium-based catalysts for non-oxidative dehydrogenation of propane,the structure-activity relationship between active sites and catalytic performance is established by adjusting the loading of different chromium-based precursors on MCM-41.XPS,H_(2)-TPR,XRD,UV,in-situ TPR,and other characterization methods are utilized to analyze the valence state of the catalyst and the existence of active species.Results show that the three chromium-based catalysts prepared all have monomeric Cr(Ⅵ),polymerized Cr(Ⅵ),and massive Cr_(2)O_(3).Among them,XPS and H2TPR results show that Cr/MCM-41(H8CrN_(2)O_(4))produces more Cr(Ⅵ);XRD.UV and Raman results prove that the monomer Cr(Ⅵ)formed by the catalyst promotes the improvement of activity.In contrast,polymerized Cr(Ⅵ)and massive Cr_(2)O_(3) hinder the performance of the catalyst.Finally,in-situ TPR proves that monomer Cr(Ⅵ)is rapidly reduced to coordinate unsaturated Cr^(3+) and Cr^(2+) when encountering propane.It is further illustrated that the monomeric Cr(Ⅵ)is the precursor of the active site of the chromium-based catalyst used in the non-oxidative dehydrogenation of propane.

关 键 词：丙烷 丙烯 Cr/MCM-41 活性位点 

分 类 号：O643.38[理学—物理化学]