International Journal of Hydrogen Energy, Vol.42, No.50, 29735-29744, 2017
Ni/Ce0.95M0.05O2-d (M = Zr, Pr, La) for methane steam reforming at mild conditions
Methane obtained from renewable resources such as biogas or biomass gasification may be reformed to produce hydrogen, an important and environmentally friendly energy vector. In the present work, nickel based catalysts supported on either pure or doped ceria (5 at% of Zr, Pr or La doping) were studied for this purpose. Catalysts were obtained by impregnation of 5 wt% nickel of ceria based supports prepared by coprecipitation by the urea method. Catalysts were calcined at three temperatures (600, 750 or 9ocrq, characterized by different techniques (XRD, H-2-TPR, TPO, OSC-OSCC, H-2-Chemisorption) and evaluated at different feed conditions and temperatures for methane steam reforming. Catalysts calcined at 900 degrees C were tested at three different reaction temperatures (600, 700 and 800 degrees C). Higher temperatures favored methane conversion and CO selectivity. For catalysts tested at 600 degrees C, increasing vapor/methane ratio caused an increase in hydrogen yield and lowered carbon formation. However, high vapor pressure was seen to favor nickel sintering. Intermediate calcination temperature (750 degrees C) enhanced nickel -support interaction leading to maximum methane conversion. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.