Özet:
The major aim of this study is to investigate the effects of different metals and supports on methane conversion and carbon monoxide selectivity in steam reforming (SR) of methane. The test matrix involves the investigation of 15wt% Ni/δ-Al2O3, 1wt% Pd/δ-Al2O3, 2wt% Pt/δ-Al2O3, 2wt% Rh/δ-Al2O3, 2wt% Ru/δ-Al2O3, 15wt% Ni/TiO2, 1wt% Pd/TiO2, 2wt% Pt/TiO2, 2wt% Rh/TiO2, 2wt% Ru/TiO2, 15wt% Ni/CeO2, 1wt%Pd/CeO2, 2wt% Pt/CeO2, 2wt% Rh/TiO2, 2wt% Ru/TiO2 catalysts, all of which are in particulate form. The catalysts are prepared by the incipient-to-wetness impregnation method and catalytic activity tests were carried out in a continous flow micro-reactor system. During the experiments, reaction temperature and molar steam-to-carbon ratio at the inlet are kept constant at 700 °C and at 2.5, respectively. The catalysts performances are investigated in terms of CH4 conversion and CO selectivity results. It has been observed that CeO2 supported Ni catalyst exhibited the better performance in terms of methane conversion and carbon monoxide selectivity than δ-Al2O3 and TiO2. For precious metals (Pd, Pt, Rh, Ru), however, CeO2 exhibited lower CO selectivity than δ-Al2O3 and TiO2, both of which gave similar selectivities. For all supports, Rh was found to be the most active metal. The catalytic activities are found to follow the decreasing order of Rh = Ni > Pt > Pd > Ru for δ-Al2O3, Rh = Ni > Ru > Pt > Pd for CeO2 and Rh > Ru > Pd > Ni > Pt for TiO2. TiO2 supported catalysts showed more stable behavior than the δ-Al2O3 and CeO2 supported ones.
