Synthesis of Hierarchical Co Micro/Nanocomposites with Hexagonal Plate and Polyhedron Shapes and Their Catalytic Activities in Glycerol Hydrogenolysis

Hierarchical Co micro/nanocomposites with hexagonal plate and polyhedron shapes in micrometer scales are synthesized through polyol reduction. Flower-surfaces Co hexagonal plates (FCHPs) show the edge lengths of the hexagonal plates about 1−2 μm in micrometer scales, and the flower-like surfaces of each individual hexagonal plate is composed of nanodiscs with diameters of about 200−250 nm and thicknesses about 20 nm. Flower-surfaces Co polyhedrons (FCPs) show the twin-hexagonal-frustum-pyramid morphology in micrometer scales with diameters of about 2−3 μm, and the flower-like surfaces of each polyhedron is also composed of nanodiscs with diameters of about 100−150 nm and thicknesses of about 20−30 nm. An oxidation-dissolution and subsequent reduction mechanism is proposed to explain the formation of their flower-like surface structure. Both FCHPs and FCPs exhibit good catalytic activities in glycerol hydrogenolysis.