Long chain ionic liquid-assisted synthesis of PS/Pd beads and hierarchical porous Pd-SiO.

Long-chain ionic liquid, 1-hexadecyl-3-methylimidazolium chloride (CmimCl), was firstly used as a linking agent to construct polystyrene (PS)/CmimCl/palladium (Pd) beads. Subsequently, the PS/CmimCl/Pd beads were used as a macroporous templating agent and CmimCl was used as a mesoporous templating agent to prepare Pd-loaded hierarchical porous silica. A systematic study was carried out addressing the influence of the amount of CmimCl and the mass ratios of (Pd)/(PS) on the PS/CmimCl/Pd beads and the Pd-loaded hierarchical porous structures. The samples were characterized by electrophoresis experiments, SEM, TEM, small-angle XRD, and N adsorption-desorption experiments. It was found that the coverage of citrate-coated Pd nanoparticles (Pd NPs) onto the PS beads can be simply tailored by changing the amount of CmimCl and the mass ratios of (Pd)/(PS). The resultant Pd-loaded hierarchical porous silica possessed a 3D ordered macroporous skeleton with a specific surface area of up to 967 m g, ordered mesoporous silica walls (SBA-3 type) and well-dispersed Pd NPs anchored on the inner walls of the spherical macroporous hollow. Importantly, the obtained Pd-loaded hierarchical porous silica exhibited an enhanced catalytic activity for the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by HO.