摘要: |
采用热重-差热分析(TG-DTA)、元素分析、氢氧滴定(HOT)、扫描电镜能谱分析(SEM-EDS)、透射电镜(TEM)等对Pt-K催化剂可能的失活机制进行研究。结果表明:积碳并非Pt-K催化剂失活的主要原因;脱氢催化剂上铂颗粒的尺寸在运转过程中没有明显的增大,即铂中心烧结也不是催化剂失活的主要原因;Pt-K催化剂在运转过程中铂分散度明显下降而且无法通过再生恢复; Pt-K/Al2O3催化剂的失活极有可能源自催化剂运转过程中钾物种对铂中心的过度覆盖作用。 |
关键词: 催化剂 邻苯基苯酚 脱氢 铂 钾 氧化铝 失活 |
DOI:10.3969/j.issn.1673-5005.2013.01.026 |
分类号::O 623.624 |
基金项目:国家“973”重点基础研究发展计划项目(2010CB226905);教育部创新团队“重质油高效转化的绿色化学与工程”项目;国家自然科学基金项目(21106185) |
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Pt-K/Al2O3 dehydrogenation catalyst for synthesis of o-phenyl phenol(Ⅱ):catalyst deactivation mechanism |
LI Yan-peng1,2, LIU Da-peng2, LIU Chen-guang1,2
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(1.State Key Laboratory of Heavy Oil Processing in China University of Petroleum, Qingdao 266580, China;2.CNPC Key Laboratory of Catalysis in China University of Petroleum, Qingdao 266580, China)
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Abstract: |
The possible deactivation mechanism of Pt-K catalyst was investigated by means of thermogravimetry-differential thermal analysis (TG-DTA), elemental analysis, H2-O2 titration (HOT), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The results show that carbon deposition is not the key factor of catalyst deactivation. The size of Pt particles hardly changes before and after reaction, and the Pt agglomeration may not be the key factor of catalyst deactivation either. For the Pt-K/Al2O3 catalyst, the Pt dispersion clearly reduces after reaction and can not be recovered even after regeneration. The deactivation of Pt-K/Al2O3 catalyst is attributed to the over-coverage effect of potassium species on the Pt active sites during the reaction. |
Key words: catalyst o-phenyl phenol dehydrogenation Pt K Al2O3 deactivation |