Ni/Ce0.95M0.05O2−d (M = Zr, Pr, La) for methane steam reforming at mild conditions

Abstract

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 900 °C), characterized by different techniques (XRD, H2-TPR, TPO, OSC-OSCC, H2-Chemisorption) and evaluated at different feed conditions and temperatures for methane steam reforming. Catalysts calcined at 900 °C were tested at three different reaction temperatures (600, 700 and 800 °C). Higher temperatures favored methane conversion and CO selectivity. For catalysts tested at 600 °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 °C) enhanced nickel-support interaction leading to maximum methane conversion.