Ni-La-B amorphous alloys supported on SiO2 and γ-Al2O3 for selective hydrogenation of benzophenone

The liquid phase selective hydrogenation of benzophenone was studied over Ni-La-B amorphous alloys supported on SiO2 and gamma-Al2O3, respectively, and the effect of the carriers was subject to detailed examination. Based on characterization data, SiO2 was suggested to have a planar structure and gamma-Al2O3 a porous structure, which markedly influenced the activity and stability of the supported catalysts. Use of ultrasound during catalyst preparation was found to make the particle sizes of the samples smaller, leading to the active particles being more dispersed on the carrier and leading to an increase in the conversion of benzophenone. Using ultrasound protocols, a Ni-La-B amorphous alloy supported on SiO2 (Ni-La-B/SiO2-u) initially showed better activity and selectivity than a Ni-La-B amorphous alloy supported on gamma-Al2O3-u (Ni-La-B/gamma-Al2O3-u); whereas Ni-La-B/SiO2-u showed poor stability compared to Ni-La-B/gamma-Al2O3-u. The main reason for the deactivation of Ni-La-B/SiO2-u was ascribed to the adsorption of reactants and products onto the catalyst surface and their coverage of the active Ni sites. (C) 2012 Elsevier B.V. All rights reserved.