Highly dispersed palladium nanoclusters incorporated on amino-functionalized silica sphere surfaces (Pd/SiO₂-NH₂) were fabricated by a simple one-pot synthesis utilizing 3-(2-aminoethylamino)propyltrimethoxysilane (AAPTS) as coordinating agent. Uniform palladium nanoclusters with an average size of 1.1 nm can be obtained during the co-condensation of tetraethyl orthosilicate and AAPTS owing to the strong interaction between palladium species and amino groups in AAPTS. The palladium particle size can be controlled by addition of AAPTS and plays a significant role in the catalytic performance. The Pd/SiO₂-NH₂ catalyst exhibits high catalytic activity for succinic acid hydrogenation with 100% conversion and 94% selectivity towards γ-butyrolactone using 1,4-dioxane as solvent at 240°C and 60 bar for 4 h. Moreover, the Pd/SiO₂-NH₂ catalyst is robust and readily reusable without loss of its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.

Morphology and crystalline-phase control of titanium dioxide is a crucial issue in the study of photocatalytic activity. Here, we present a facile synthetic path combing the sol–gel method with solvothermal treatment to form hybrid mesoporous and microporous TiO₂. The TiO₂ precursor was obtained by the sol–gel method, and this was self-assembled into mesopores and micropores by NH₄F corrosiveness on the surface of TiO₂ under hydrothermal conditions. Powder X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), X-ray photoelectron spectroscopy (XPS), N₂ adsorption measurements, transmission electron microscopy (TEM) and Raman spectroscopy were used to characterise the titania powders. The results reveal that NH₄F not only improved the formation of the crystallised anatase phase but also served as a corrosive agent modified on the surface of TiO₂ precursors. Defective voids among these nanoparticles formed micropores by hydrothermal reaction of NH₄F and TiO₂ over a long time. When the NH₄F concentration was 1.0 mol L⁻¹, micropores became dominant,and few mesopores were obtained, and this results in a smaller average pore size. Thus, mesoporous and microporous structures were formed. Furthermore, these crystallised mesoporous and microporous anatase titania nanoparticles with uniform structure and high surface area have a higher photocatalytic activity for azo dye degradation under near UV irradiation.