Abstract:
A series of Ni/Al₂O₃ and modified Ni-M/Al₂O₃ (M= La, Na, K, Ca and Ba ) catalysts have been prepared and characterized by XRD, BET, XPS, TGA, TEM and SEM. The performance of these catalysts for simultaneous oxidative conversion and CO₂ reforming of methane to syngas was evaluated using a fixed-bed reactor. The results indicated that the catalytic activity of Ni/Al₂O₃ increased with Ni loading, and reached maximum at 12% Ni loading. The La-modified Ni/Al₂O₃ exhibited an excellent catalytic activity and stability within 20 h as compared with unmodified and Na-modified ones. It was found that the addition of La decreased the particle size of nickel, thus increased the Ni dispersion accordingly as indicated by the characterization data. The catalytic activity of Na-modified Ni/Al₂O₃decreased obviously only after 6 h of reaction due to aggregation of metallic Ni particles. Hence, it was suggested that the sintering of Ni particles dominated the catalyst deactivation during the catalytic reaction process.
