Oxidative Coupling of Methanol with Molecularly Adsorbed Oxygen on Au Surface to Methyl Formate.

Supported Au catalysts efficiently catalyze the oxidative coupling of methanol with O to methyl formate, in which the atomic O species (O(a)) formed via O dissociation on the Au surface has been considered as the active oxygen species. Herein we report for the first time that the oxidative coupling of methanol can occur facilely with molecularly adsorbed O species (O(a)) on a Au(997) surface at temperatures as low as around 125 K, while that with O(a) occurs at around 175 K. Both experimental and theoretical calculation results demonstrate a novel reaction mechanism of oxidative coupling of CHOH with (a) via a dioxymethylene (HCO) intermediate, resulting in the production of both HCOOCH and HCOCH.

A new insight into the theoretical design of highly dispersed and stable ceria supported metal nanoparticles.

How to design and develop ceria supported metal nanoparticles (M/CeO) catalysts with high performance and sintering resistance is a great challenge in heterogeneous catalysis and surface science. In the present work, we propose two ways to improve the anti-sintering capability of M/CeO catalysts. One is to introduce Ti atom on CeO (1 1 1) to form monatomically dispersed Ti, TiO or TiO-like species on ceria.

Effects of strong interactions between Ti and ceria on the structures of Ti/CeO.

The effects of strong interactions between Ti and ceria on the structures of Ti/CeO(111) are systematically investigated by density functional theory calculation. To our best knowledge, the adsorption energy of a Ti atom at the hollow site of CeO is the highest value (-7.99 eV) reported in the literature compared with those of Au (-0.

Choosing a proper exchange-correlation functional for the computational catalysis on surface.

To choose a proper functional among the diverse density functional approximations of the electronic exchange-correlation energy for a given system is the basis for obtaining accurate results of theoretical calculations. In this work, we first propose an approach by comparing the calculated ΔE0 with the theoretical reference data based on the corresponding experimental results in a gas phase reaction. With ΔE0 being a criterion, the three most typical and popular exchange-correlation functionals (PW91, PBE and RPBE) were systematically compared in terms of the typical Fischer-Tropsch synthesis reactions in the gas phase.

Hydrogen fluoride adsorption and reaction on the α-Al2O3(0001) surface: a density functional theory study.

The adsorption and reaction behaviors of HF on the α-Al(2)O(3)(0001) surface are systematically investigated using density functional theory method. By increasing the number of HF molecules in a p(2 × 1) α-Al(2)O(3)(0001) slab, we find that HF is chemically dissociated at low coverage; while both physical and dissociative adsorption occurs at a 3/2 monolayer (ML) coverage. At the same coverage (1.

A DFT study of the structures of Au(x) clusters on a CeO2(111) surface.

Studying the structures of metal clusters on oxide supports is challenging due to their various structural possibilities. In the present work, a simple rule in which the number of Au atoms in different layers of Au(x) clusters is changed successively is used to systematically investigate the structures of Au(x) (x=1-10) clusters on stoichiometric and partially reduced CeO(2)(111) surface by DFT calculations. The calculations indicate that the adsorption energy of a single Au atom on the surface, the surface structure, as well as the Au-Au bond strength and arrangement play the key roles in determining Au(x) structures on CeO(2)(111).

Synthesis of functionalized 2,3-dihydroisoxazoles by domino reactions in water and unexpected ring-opening reactions of 2,3-dihydroisoxazoles.

α,α-Dicyanoolefins react with hydroxylamine to afford 2,3-dihydroisoxazoles (2,3-dihydroisoxazoles can be easily isolated by filtration) in excellent yields under mild and environmentally benign conditions. A one-pot reaction in tandem with an unexpected ring-opening of 2,3-dihydroisoxazoles has been developed as well.

A density functional theory study of the CH(2)I(2) reaction on Ag(111): Thermodynamics, kinetics, and electronic structures.

Density functional theory calculation was performed to study the adsorption and reaction of CH(2)I(2) on Ag(111). Thermodynamically favorable reactions of CH(2)I(2) on Ag(111) are C-I bond ruptures and CH(2) coupling to form ethylene. The energy barriers for the C-I bond ruptures of chemisorbed CH(2)I(2) on Ag(111) are 0.