Studies of mechanisms and kinetics of methane and ethane steam reforming on nickel catalysts

Methane and ethane adsorption/desorption and reaction on steam-reforming catalysts, Ni(INCO), Ni/ZrO{dollar}sb2{dollar}, and Ni/CaAl{dollar}sb2{dollar}O{dollar}sb4{dollar}, were studied by temperature-programmed desorption (TPD), temperature-programmed surface reaction (TPSR), and thermogravimetric (TGA) techniques.; The data show that only a fraction of the methane adsorbed (determined by TPSR with H{dollar}sb2{dollar}) on nickel catalysts is desorbed during TPD experiments. The results of TPD indicate supports and promoters affect the adsorption of methane and ethane, and transformation of adsorbed carbon species.; Several carbon types formed during methane and ethane adsorptions including {dollar}alpha{dollar}, {dollar}beta{dollar}, {dollar}gamma{dollar}, vermicular (v), and graphitic (c) carbon can be identified by TPSR. These data indicate that the distribution of these carbon forms is also strongly a function of adsorption temperature and catalyst.; The results show that there are significant quantities of CH{dollar}sb4{dollar}, CO, and CO{dollar}sb2{dollar} desorbed during TPSR reaction of H{dollar}sb2{dollar}O with preadsorbed CH{dollar}sb4{dollar}, CD{dollar}sb4{dollar} and C{dollar}sb2{dollar}H{dollar}sb6{dollar}. The agreement between previously reported steady-state and the unsteady-state steam reforming rates of this study indicates that the steam-reforming kinetic data can be quantitatively measured by TPSR experiments.