Steam reforming of simulated biogas over plate Ni-Cr catalysts: Influence of pre-oxidation on catalytic activity

Abstract

The activity and stability of Ni-Cr plate catalysts were significantly enhanced by a pretreatment process involving pre-oxidation at >= 600 degrees C with subsequent reduction at 700 degrees C. Analytical techniques including SEM, TEM, and XPS-depth profiling studies revealed that the pretreatment induced surface reconstruction in the bulk Ni-Cr material generating new Ni sites with improved activity. The catalytic activity was highly dependent upon the oxidation temperature. In addition to the creation of novel Ni sites, chromium oxide acted as a structural promoter to suppress sintering of the Ni active sites. Activation of the Ni-Cr plate catalyst via pretreatment at 700 degrees C resulted in improved stability for biogas reforming reactions over a period of 100 h. Moreover, the stability of the reforming catalyst was sustained over 100 h with a steam/CH4 ratio of >= 1.5. The influences of temperature, inlet H2O/CH4 ratio, and CH4/CO2 ratios on the steam reforming of biogas were further studied. (C) 2014 Elsevier B.V. All rights reserved.