Silica-supported Au@hollow-SiO₂ particles with outstanding catalytic activity prepared via block copolymer template approach

Catalytically active Au@hollow-SiO2 particles embedded in porous silica support (Au@hollow-SiO2@PSS) were prepared by using spherical micelles from poly(styrene)-block-poly(4-vinyl pyridine) block copolymer as a sacrificial template. Drastic increase of the shell porosity was observed after pyrolytic removal of polymeric template because the stretched poly(4-vinyl pyridine) chains interpenetrating with silica shell acted as an effective porogen. The embedding of Au@hollow-SiO2 particles in porous silica support prevented their fusion during pyrolysis. The catalytic activity of Au@hollow-SiO2@PSS was investigated using a model reaction of catalytic reduction of 4-nitrophenol and reductive degradation of Congo redazo-dye. Significantly, to the best of our knowledge, Au@hollow-SiO2@PSS catalyst shows the highest activity among analogous systems reported till now in literature. Such high activity was attributed to the presence of multiple pores within silica shell of Au@hollow-SiO2 particles and easy accessibility of reagents to the catalytically active sites of the ligand-free gold surface through the porous silica support. (C) 2016 Elsevier Inc. All rights reserved

La₆Pd₁₃Cd₄ and Ce₆Pd₁₃Cd₄ with palladium-centred rare earth octahedra: synthesis, structure, and chemical bonding

he palladium-rich cadmium compounds La6Pd13Cd4 and Ce6Pd13Cd4 were synthesized by induction melting the elements in sealed tantalum ampoules and subsequent annealing. They were characterized by X-ray powder and single-crystal diffraction: Na16Ba6N type, ...

A One-Pot Approach to Mesoporous Metal Oxide Ultrathin Film Electrodes Bearing One Metal Nanoparticle per Pore with Enhanced Electrocatalytic Properties

The controlled incorporation of single metal nanoparticles within the pores of mesostructured conducting metal oxide ultrathin films is demonstrated, taking advantage of the controlled metal precursor loading capacities of PS-b-P4VP inverse micellar templates. The presented one-pot approach denoted as Evaporation-Induced Hydrophobic Nanoreactor Templating (EIHNT) unusually involves the nanostructuration of the metal oxide via the hydrophobic shell of the micellar template, while the concomitant nanostructuration of the metal is achieved via its confinement in the hydrophilic micellar core. This approach is applied to tin-rich ITO and gold, to yield unique mesoporous tin-rich ITO ultrathin film electrodes remarkably loaded with one size-controlled gold nanoparticle per pore. Interestingly, the resulting tin-rich ITO-supported gold nanoparticles exhibit improved catalytic activity and durability in electrocatalytic CO oxidation compared to similarly sized gold nanoparticles supported on conventional ITO coatings