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Cr^6+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Cr^6+和Oβ是催化氧化NO的重要活性物种。
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 Cr^6+,indicating that Co-Cr has good synergistic catalysis.XPS revealed that the Co doping greatly increased the content of Cr^6+,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 Cr^6+ and Oβ are important active species for the catalytic oxidation of NO.
作者
魏炜
牟一蒙
梁红
李树华
乔智威
彭峰
WEI Wei;MOU Yi-Meng;LIANG Hong;LI Shu-Hua;QIAO Zhi-Wei;PENG Feng(Guangzhou Key Laboratory for New Energy and Green Catalysis,College of Chemistry andChemical Engineering,Guangzhou University,Guangzhou 510006,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2019年第6期978-986,共9页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.21576058)
广东省自然科学基金(No.2018A030313516)
广东省发展专项资金(No.201804010449)资助项目
