A Study on Methanation of Carbon Monoxide over Catalysts NiO/TiO2 and NiO/-Al2O3
AbstractThe catalyst 7.5% NiO/TiO2 and seven samples of NiO/ -Al2O3 with NiO content from 7.5% to 60% have been obtained and studied. Physico-chemical characteristics of the catalysts were determined by methods of Adsorption (BET), X-ray Diffraction (XRD), Temperature- Programmed Reduction (TPR) and Hydrogen Pulse Titration. The catalytic properties of the obtained samples were investigated in the reaction of CO methanation at temperatures 180 – 220C and mole ratios hydrogen/carbon monoxide 25-100. It has been found that the optimal regime for catalyst treatment is calcination at 600C and reduction at 400C. The catalyst 7.5% NiO/TiO2 expressed very high activity but in case of NiO/Al2O3 for having high activity it was necessary to raise the content of NiO up to 37.7%. This catalyst has been indicated to be the most active in all the studied conditions. The determining factors for expressing high activity in the catalyst 7.5% NiO/TiO2 are the presence of spinel NiTiO3 and the optimal average size of nickel assemblies but in the catalyst 37.7% NiO/Al2O3 – the optimal size of active centers, big values of specific surface area and content of NiO and the high thermal stability.
điểm / đánh giá