不同金属负载对Cr/Al2O3-TiO2催化剂结构及氧化NO性能的影响
Effect of Different Metal Loading on the Structures and Catalytic Oxidation NO Performance of Cr/Al2O3-TiO2 Catalysts
作者单位E-mail
魏炜 广州大学化学化工学院, 能源与催化研究所, 广州 510006  
牟一蒙 广州大学化学化工学院, 能源与催化研究所, 广州 510006  
梁红 广州大学化学化工学院, 能源与催化研究所, 广州 510006 lhong@zghu.edu.cn 
李树华 广州大学化学化工学院, 能源与催化研究所, 广州 510006  
乔智威 广州大学化学化工学院, 能源与催化研究所, 广州 510006  
彭峰 广州大学化学化工学院, 能源与催化研究所, 广州 510006 fpeng@zghu.edu.cn 
摘要: 采用溶胶-凝胶法和浸渍法制备Cr/Al2O3-TiO2催化剂,在考察不同Cr负载量的基础上,研究不同金属负载与焙烧温度对Cr/Al2O3-TiO2催化剂结构与性能影响。程序升温氧化(TPO)结果表明,当Cr负载量为10%(w/w)时具有较好的催化活性;不同金属负载Cr/Al2O3-TiO2时,负载Co及在焙烧温度为550℃时催化剂具有较好的活性。通过程序升温还原(H2-TPR)表征发现,Co的负载使催化剂的低温氧化还原能力逐渐提高,表明Co-Cr具有较好的协同催化作用。X射线光电子能谱(XPS)表征表明,Co增加了Cr6+和表面吸附氧(Oβ)含量,随着焙烧温度的升高(450~550℃),晶格氧不断向催化剂表面流动,表面化学吸附氧Oβ比例逐渐增加,导致催化活性不断升高,说明Cr6+和Oβ是催化氧化NO的重要活性物种。
关键词: 负载  Co-Cr/Al2O3-TiO2  焙烧温度  催化氧化  NO
基金项目: 国家自然科学基金(No.21576058),广东省自然科学基金(No.2018A030313516)和广东省发展专项资金(No.201804010449)资助项目。
Abstract: A series of Cr/Al2O3-TiO2 catalysts were successfully synthesized by the combination of sol-gel method and impregnation method for catalytic oxidation of NO. The effects of Cr load, different metal loading and calcination temperature on the physical-chemical properties of Cr/Al2O3-TiO2 catalysts were exhaustively investigated by using different characterization techniques, such as the temperature programmed oxidation (TPO), X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), N2 adsorption-desorption method and X-ray photoelectron spectroscopy (XPS). The TPO results showed that the 10%(w/w) Cr/Al2O3-TiO2 possessed the highest performance. Compared the doping of different metals, Co-Cr/Al2O3-TiO2 obtained excellent catalytic activity and high specific surface area at 550℃ calcination temperature. H2-TPR show that both the Co loading and calcination temperature can significantly improve the low-temperature redox ability of the catalyst, and be beneficial to form more active species of Cr6+, indicating that Co-Cr has good synergistic catalysis. XPS revealed that the Co doping greatly increased the content of Cr6+, surface adsorbed oxygen (Oβ), and oxygen vacancies. Besides, when the calcination temperature increased (450~550℃), the lattice oxygen continuously moved to the surface of catalyst and increased the ratio of Oβ, leading to the further enhancement of catalytic activity of Co-Cr/Al2O3-TiO2. Based the characterization results and catalytic performance of Cr/Al2O3-TiO2, it is proved that both Cr6+ and Oβ are important active species for the catalytic oxidation of NO.
Keywords: loading  Co-Cr/Al2O3-TiO2  calcination temperature  catalytic oxidation  NO
投稿时间:2018-12-17 修订日期:2019-03-14
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魏炜,牟一蒙,梁红,李树华,乔智威,彭峰.不同金属负载对Cr/Al2O3-TiO2催化剂结构及氧化NO性能的影响[J].无机化学学报,2019,35(6):978-986.
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