Plasma-Prepared Ni/Al2O3: Preparation, Characterization and Toluene Hydrogenation

Abstract

Nano-nickel particles were prepared using hydrogen arc plasma method and new nano-nickel hydrogenation catalysts were prepared through calcinating mixtures of the plasma-prepared nano-nickel particles and a ?-alumina support. The catalysts were characterized by using SEM, XRD, and TPR. The activities of the catalysts were evaluated through the hydrogenation of toluene in a fixed be microreactor. Catalysts prepared by conventional comulling and impregnation methods were also examined for comparative purposes. The characterization results showed that the nano-nickel catalysts had an egg-shell structure in terms of nickel-alumina distribution, with most of the nickel located at the outer surface of the catalyst particles. The hydrogenation experiments showed that the nano-nickel catalyst provided much higher activities than those co-precipitated and impregnated nickel catalysts with similar nickel contents. However, both types of catalysts followed first-order reaction kinetics and similar activation energies were observed.