Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (7): 1325-1331.doi: 10.3866/PKU.WHXB201405042

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Effect of CO2 Pretreatment Operation Conditions on the Catalytic Performance and Structure of Ni-Co Bimetallic Catalyst

ZHAO Jian1,2, ZHOU Wei2,3, MA Jian-Xin1,2,3   

  1. 1. School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China;
    2. Clean Energy Automotive Engineering Center, Tongji University, Shanghai 201804, P. R. China;
    3. School of Automotive Studies, Tongji University, Shanghai 201804, P. R. China
  • Received:2014-02-06 Revised:2014-05-04 Published:2014-06-30
  • Contact: MA Jian-Xin E-mail:jxma@tongji.edu.cn
  • Supported by:

    The project was supported by the Ministry of Science and Technology International Cooperation Program, China (2010DFA64080) and National High Technology Research and Development Program of China (863) (2011AA11A275).

PDF

1239

Like

Abstract:

The performance of the Ni-Co bimetallic catalyst was significantly improved by a novel H2 and CO2 (HCD) pretreatment in the dry reforming of methane compared with traditional H2 pretreatment. The effects of the HCD pretreatment operating conditions, such as pretreatment time, temperature, gas feeding ratio, and gas flow rate, on the catalytic performance of Ni-Co bimetallic catalyst were investigated. The optimal pretreatment time, temperature, gas feeding ratio (CH4/CO2), and gas flow rate were 0.5-1 h, 780-800 ℃, 0:10, and 175-200 mL·min-1, respectively. Biogas was simulated with CH4 and CO2 in a volume ratio of 1 and without any other diluted gas. The catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetry (TG) coupled to differential scanning calorimetry (DSC). In a 511 h stability test under the optimized operating conditions, the catalyst pretreated with both H2 and CO2 exhibited excellent stability. The average conversions of CH4 and CO2, selectivities for H2 and CO, and volume ratio of H2/CO were 96%, 97%, 98%, 99%, and 0.98, respectively. The average carbon deposition rate over the Ni-Co bimetallic catalyst was only about 0.2 mg·g-1·h-1. The characterization results revealed that the sintering speed of the metal greatly decreased with testing time, and the metal particle will not greatly sinter with further testing time. The amount of deposited carbon on the catalyst gradually decreased and growth of filamentous carbon over the surface of the catalyst could be inhibited. The performance of the Ni-Co bimetallic catalyst was significantly improved by a novel H2 and CO2 (HCD) pretreatment in the dry reforming of methane compared with traditional H2 pretreatment. The effects of the HCD pretreatment operating conditions, such as pretreatment time, temperature, gas feeding ratio, and gas flow rate, on the catalytic performance of Ni-Co bimetallic catalyst were investigated. The optimal pretreatment time, temperature, gas feeding ratio (CH4/CO2), and gas flow rate were 0.5-1 h, 780-800 ℃, 0:10, and 175-200 mL·min-1, respectively. Biogas was simulated with CH4 and CO2 in a volume ratio of 1 and without any other diluted gas. The catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetry (TG) coupled to differential scanning calorimetry (DSC). In a 511 h stability test under the optimized operating conditions, the catalyst pretreated with both H2 and CO2 exhibited excellent stability. The average conversions of CH4 and CO2, selectivities for H2 and CO, and volume ratio of H2/CO were 96%, 97%, 98%, 99%, and 0.98, respectively. The average carbon deposition rate over the Ni-Co bimetallic catalyst was only about 0.2 mg·g-1·h-1. The characterization results revealed that the sintering speed of the metal greatly decreased with testing time, and the metal particle will not greatly sinter with further testing time. The amount of deposited carbon on the catalyst gradually decreased and growth of filamentous carbon over the surface of the catalyst could be inhibited. Thereby, great catalytic activity and stability could be obtained during the dry reforming of methane reaction.

Key words: Biogas reforming, Hydrogen production, Ni-Co catalyst, Pretreatment, Operation condition