Inorganic Chemicals Industry ›› 2021, Vol. 53 ›› Issue (4): 95-100.doi: 10.11962/1006-4990.2020-0265

• Catalytic Materials • Previous Articles     Next Articles

Effect of calcination temperature on physicochemical properties and catalytic performance of MnZnOx

Xiao Yihan1,2,3,Cao Jianxin1,2,3(),Liu Fei1,2,3(),Yi Yun1,2,3   

  1. 1. School of Chemistry and Chemical Engineering,Guizhou University,Guiyang 550025,China
    2. Guizhou Key Laboratory for Green Chemical and Clean Energy Technology
    3. Guizhou Engineering Research Center of Efficient Utilization for Industrial Waste
  • Received:2020-10-15 Online:2021-04-10 Published:2021-04-23
  • Contact: Liu Fei E-mail:jxcao@gzu.edu.cn;ce.feiliu@gzu.edu.cn

Abstract:

The rapid development of global industry had aggravated a large amount of greenhouse gas (CO2)emissions.It is of great significance to convert CO2 to methanol by reduction and activation of high energy hydrogen molecules.Wet chemical co-precipitation strategy was employed to fabricate the MnZnOx solid solution catalyst which realized the hydrogenation of CO2 to methanol and the influence of calcination temperature on physicochemical properties and catalytic performance of the catalysts were fully investigated in this paper.X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),N2 adsorptiondesorption,CO2-TPD and H2-TPR techniques were used to characterize the physicochemical properties of the catalysts calcined at various temperature.The results showed that the calcination temperature had significant impact on the crystalline phase compositions,pore structure properties,CO2 adsorption characteristics and surface oxygen vacancy concentrations of MnZnOx.Although the homogeneous solid solution structure could be formed at lower temperature,the crystallinity of the main crystal phase ZnO was inferior.Too high calcination temperature made the solute component MnxOy crystallize in the form of Mn3O4 and the mixed crystal phase of Mn3O4 and ZnO was formed in the structure,resulting in the decrease of specific surface area and mesoporous pore volume.MnZnOx catalyst calcinated at 500 ℃ had a solid solution structure with abundant surface oxygen vacancy,large CO2 adsorption and mesoporous pore volume and uniform dispersion of solute components.Under the conditions as follows:reaction pressure of 3.0 MPa,reaction space velocity(GHSV) of 14 400 mL/(g·h) and V(H2)∶V(CO2)∶V(N2)=72∶24∶4,the MnZnOx at 380 ℃ exhibited excellent catalytic performance with methanol selectivity of 86.1%,CO2 conversion of 16.0% and methanol STY of 0.68 g MeOH/(h·gcat).

Key words: MnZnOx, solid solution structure, calcining temperature, oxygen vacancy, CO2 hydrogenation

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