We report the synthesis of a new Au nanocatalyst with increased thermal stability. This catalyst system consisted of gold nanoparticles attached to functionalized TiO2/SiO2 core-shell nanocomposites, together with the encapsulation of mesoporous silica. The synthesis process mainly involved four steps, which included the synthesis of the TiO2/SiO2 core-shell composites, synthesis of the Au/TiO2...

We present a detailed study of the mechanism for oxidative heteroarylation, based on DFT calculations and experimental observations. We propose binuclear Au(II)-Au(II) complexes to be key intermediates in the mechanism for gold catalyzed oxidative heteroarylation. The reaction is thought to proceed via a gold redox cycle involving initial oxidation of Au(I) to binuclear Au(II)-Au(II) complexes ...

2.4. Molecular Beam Epitaxy 366 2.5. Laser Ablation 367 2.6. Silicon Monoxide Evaporation 367 3. Catalyst Materials 368 3.1. Gold as Catalyst 368 3.2. Alternative Catalyst Materials 369 3.2.1. Type-A, Au-like Catalysts 370 3.2.2. Type-B, Low Si Solubility Catalysts 371 3.2.3. Type-C, Silicide Forming Catalysts 371 4. Crystallography 372 5. Heterostructures 373 6. Surface Induced Lowering of the...

This paper remarks the general correlations of the shape and crystallinity of titanium dioxide (TiO₂) support on gold deposition and carbon monoxide (CO) oxidation. It was found that due to the larger rutile TiO₂ particles and thus the pore volume, the deposited gold particles tended to agglomerate, resulting in smaller catalyst surface area and limited gold loading, whilst anatase TiO₂ enabled...

The principal purpose of this study is to present a new design for preparing highly active immobilized gold nanoparticle-based plasmonic photocatalysts. Gold nanoparticles were loaded on rutile TiO2 particles with a mean size of 80 nm (Au/TiO2) by the deposition precipitation method. The surface of SnO2 particles with a mean size of 100 nm was modified by copper(ii) oxide clusters (CuO/SnO2) wi...

A synthetic method to prepare tricyclic bridged heptenones and hexenones from gold(I)-catalyzed double cycloisomerization of 1,11-dien-3,9-diyne benzoates is described. A divergence in product selectivity was achieved by fine-tuning the steric nature of the ligand of the Au(I) catalyst. In the presence of [MeCNAu(JohnPhos)](+)SbF6(-) (JohnPhos = (1,1'-biphenyl-2-yl)-di-tert-butylphosphine) as t...

Changes in a Au/TiO(2) catalyst during the activation process from an as-prepared state, consisting of supported AuO(x)(OH)(4-2x)(-) species, were monitored with X-ray absorption spectroscopy and FTIR spectroscopy, complemented with XPS, microcalorimetry, and TEM characterization. When the catalyst was activated with H(2) pulses at 298 K, there was an induction period when little changes were d...

The deuterium isotope effect in the steady state CO oxidation rate over Au/ -Al2O3 in the presence of H2 or H2O and the effect of pretreatment on an uncalcined catalyst were studied. In a reaction feed containing 1% CO, 0.5% O2, and 40.5% H2 at room temperature, CO oxidation exhibited a deuterium isotope effect (kH/kD) of 1.4 ± 0.2. The rate of D2 oxidation was also slower than the oxidation of...

Research to develop highly versatile, chiral, heterogeneous catalysts for asymmetric organic transformations, without quenching the catalytic reactivity, has met with limited success. While chiral supramolecular structures, connected by weak bonds, are highly active for homogeneous asymmetric catalysis, their application in heterogeneous catalysis is rare. In this work, asymmetric catalyst was ...

We decorated HS-functionalized cellulose nanocrystallite (CNC) films with monodisperse Au nanoparticles (AuNPs) to form a novel nanocomposite catalyst AuNPs@HS-CNC. The uniform, fine AuNPs were made by the reduction of HAuCl4 solution with thiol (HS-) group-functionalized CNC films. The AuNPs@HS-CNC nanocomposites were examined by X-ray photoelectron spectroscopy (XPS), TEM, ATR-IR and solid-st...