n-Dodecane steam reforming catalyzed by Ni-Ce-Pr catalysts. Part 1: Catalyst preparation and Pr doping

摘要

Catalytic steam reforming of long-chain hydrocarbons has drawn great attention for hydrogen production, which can be used for on-board/on-site fuel cell. In this study, various ceria (or Pr-doped ceria) supported Ni catalysts have been prepared by two different methods (impregnation method and sol-gel method), which are denoted as 10Ni/Ce1-xPrxO2and 10Ni-Ce1-xPrxO2(x?=?0 or 0.2) respectively. Steam reforming ofn-dodecane has been carried out to evaluate catalytic performance of the obtained catalysts at high LHSV (15?ml/gcat?h), low temperature (600?°C) and low mole ratio of water-to-carbon (2) in a fixed-bed tubular reactor. Results show that both the formation of nickel-ceria strong metal support interaction and Pr doping increase its catalytic performance. 10Ni-Ce0.8Pr0.2O2prepared by sol-gel method exhibits the highest activity (100% conversion ofn-dodecane) and stability of hydrogen production (5917.1?μmol/min) together with lowest coke deposition (0.0251?g/gcat?h). Various techniques including XRD, nitrogen adsorption-desorption, H2-TPR, TEM/STEM, SEM-EDS, XPS, TG/DTG and Raman spectra have been employed to characterize the fresh and spent catalysts. The evaluated activity and stability of ceria supported Ni catalyst is ascribed to the strong interaction between metal and support. In addition, the oxidation of deposited coke on metal is enhanced by the doping of Pr due to its high oxygen storage-release capability.