Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (5): 923-931.doi: 10.3866/PKU.WHXB201403051

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effect of Chromium Doping on the Catalytic Behavior of Cu/ZrO2/CNTs-NH2 for the Synthesis of Methanol from Carbon Dioxide Hydrogenation

WANG Guan-Nan1, CHEN Li-Min1,2, GUO Yuan-Yuan1, FU Ming-Li1, WU Jun-Liang1, HUANG Bi-Chun1,2, YE Dai-Qi1,2   

  1. 1 Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, Guangzhou 510006, P. R. China;
    2 College of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
  • Received:2014-01-08 Revised:2014-03-03 Published:2014-04-25
  • Contact: CHEN Li-Min, YE Dai-Qi E-mail:liminchen@scut.edu.cn;cedqye@scut.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21207039, 51108187, 0978103), Natural Science Foundation of Guangdong Province, China (S2011010000737), Specialized Research Fund for the Doctoral Program of Higher Education, China (20110172120017), and Scientific Research Foundation for Returned Scholars, Ministry of Education of China (2012).

Abstract:

A series of Cu/ZrO2/CNTs-NH2 catalysts with various chromium dopings were prepared using a coprecipitation method for the synthesis of methanol by the hydrogenation of CO2. The impact of the addition of chromium on the catalytic performance of the Cu/ZrO2/CNTs-NH2 catalyst was investigated in a fixed-bed plug flow reactor. When the chromium loading was set to 1% of the total amount of Cu2+ and Zr4+, the methanol yield increased to a maximum of 7.78% (reaction conditions: 3.0 MPa, 260 ℃, V(H2):V(CO2):V(N2)=69:23:8 and gaseous hourly space velocity (GHSV)=3600 mL·h-1·g-1). The catalysts were characterized by N2 physisorption, X-ray diffraction (XRD), temperature-programmed desorption of H2 (H2-TPD), X-ray photoelectron spectroscopy (XPS), temperature- programmed desorption of CO2 (CO2-TPD), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The results of these analyses indicated that the introduction of chromium reduced the size of the Cu nanoparticles, enhanced the dispersion of the Cu species, inhibited the phase transformation and sintering of ZrO2, increased the specific surface area, enhanced the amount of CO2 adsorbed, and promoted the conversion of weakly adsorbed CO2 species to strongly adsorbed CO2 species. Taken together, these factors lead to a high methanol yield. However, when the chromium loading was greater than 1%, the amount Cu and Zr on the surface, as well as the size of the Cu nanoparticle reduced considerably, which led to a significant reduction in the adsorption of CO2 species. This effect also facilitated the formation of strongly adsorbed CO2 species, leading to lower methanol yields.

Key words: CNTs-NH2, Chromium, Copper, Zirconia, Methanol synthesis, Carbon dioxide hydrogenation

MSC2000: 

  • O643