Highly active Co-B, Co-Mo(W)-B amorphous nanotube catalysts for the selective hydrogenation of cinnamaldehyde

High-quality, noncrystalline alloy Co-B, Co-Mo-B, and Co-W-B nanotubes were prepared by chemical co-reduction in cobalt chloride and ammonium heptam-olybdate (or ammonium metatungstate) containing a liquid crystal system. The nanotubes were characterized by powder X-ray diffraction, inductively coupled plasma spectrometry, N-2 adsorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic performances of the as-prepared materials were carefully investigated for the selective hydrogenation of cinnamaldehyde in the liquid phase under moderate pressure. Higher catalytic activity and selectivity to cinnamylalcohol were exhibited by the nanotubular catalysts in the selective hydrogenation of cinnamaldehyde as compared with those of corresponding nanoparticles. The excellent performance of the nanotubes was correlated to their high specific surface area and tubular morphology. Mo and W effectively promoted the overall rate and yield of unsaturated alcohol. Aside from the higher catalytic activity, the structural stabilities of the nanotubular catalysts were also improved by doping in consecutive catalytic runs.