Preparation and characterization of amorphous Co-B catalysts with mesoporous structure

Amorphous Co-B alloy catalyst with mesoporous structure was firstly prepared via reduction of cobalt acetate by potassium borohydride in the presence of an organic template hexadecyl-trimethyl-ammonium bromide. The as-prepared mesoporous Co-B was characterized by Fourier transform infrared (FTIR), X-ray powder diffraction (XRD), scanning electron micrograph (SEM), inductively coupled plasma (ICP), X-ray photo-electron spectroscopy (XPS), cyclic voltammetry (CV) measurement, N-2 adsorption-desorption, CO temperature-programmed desorption (TPD), and magnetic performance test. Investigations demonstrated that such mesoporous structure has a pronounced influence on the magnetic properties of Co-B alloy and the enhanced magnetic performance enables the as-prepared mesoporous Co-B to be recycled by magnetic method in the liquid-phase cinnamaldehyde (CMA) hydrogenation. During the hydrogenation, the as-prepared mesoporous Co-B exhibited higher cinnamaldehyde conversion and cinnamyl alcohol (CMO) selectivity than the regular Co-B obtained without using organic template, which is attributed to the larger specific surface area and the stronger affinity to C=O. After 11 cycles, the conversion of cinnamaldehyde over the mesoporous Co-B was 85.2%, which is higher than that of the fresh regular Co-B. The good cycle performance is attributed to its preserved mesoporous structure in spite of the collapse of some mesopores during cycling. In addition, the increase of selectivity for cinnamyl alcohol after several cycles is attributed to the growth of particle size. (c) 2007 Elsevier B.V. All rights reserved.