Three-dimensional flower-like OMS-2 supported Ru catalysts for application in the combustion reaction of o-dichlorobenzene†
Three-dimensional flower-like OMS-2 samples with different morphologies were synthesized by K2CrO4 and MnSO4 under acidic conditions. The reactant concentrations of K2CrO4 and MnSO4 could regulate the growth rate and surface energy of crystals, and in turn, affect the formation of complex structures. In the case of a low concentration of reactants, the morphology of the obtained OMS-2 sample was a dendritic structure formed by smooth-surfaced hexagonal prism nano-rods self-assembled along the central axis. As the concentration of the reactants increased, the morphology of the sample transformed to an urchin-like structure composed of rough-surfaced, needle-shaped nano-rods pointing outward from the core. The growth mechanisms of the samples were investigated via TEM, SEM, XRD and Raman spectroscopy. Each nano-rod was generated by the laterally oriented attachment of the primary nano-fibers run mainly in the (200) crystal faces along the axis. The irregular lattice fringes of the fusion interface demonstrate the formation of defects. The morphology, surface roughness and defect content of the samples were dependent on the concentration of the reactants. The as-prepared OMS-2 samples were employed as supports to load 0.8% Ru by a precipitation method. Physicochemical property studies showed that there were abundant defect sites and better Ru4+ dispersion with increasing OMS-2 carrier surface roughness. Ru/OMS-Chig exhibited good catalytic performance in the catalytic combustion of o-dichlorobenzene.