Zr-based metal-organic frameworks (MOFs) have been shown to be excellent catalyst supports in heterogeneous catalysis due to their exceptional stability. Additionally, their crystalline nature affords the opportunity for molecular level characterization of both the support and the catalytically active site, facilitating mechanistic investigations of the catalytic process. We describe herein the...

The alkylation of isobutane with light alkenes plays an essential role in modern petrochemical processes for the production of high-octane gasoline. In this study we have employed periodic DFT calculations combined with microkinetic simulations to investigate the complex reaction mechanism of isobutane-propene alkylation catalyzed by zeolitic solid acids. Particular emphasis was given to addres...

Supported gold nanoparticles are highly selective catalysts for a range of both liquid-phase and gas-phase hydrogenation reactions. However, little is known about their stability during gas-phase catalysis and the influence of the support thereon. We report on the activity, selectivity, and stability of 2-4 nm Au nanoparticulate catalysts, supported on either TiO2 or SiO2, for the hydrogenation...

The structure and surface composition of binary oxides consisting of CrO(x) and VO(x) dispersed on alumina and their effects on the rate and selectivity of oxidative dehydrogenation (ODH) of propane were examined and compared with those for CrO(x) and VO(x) dispersed on alumina. VO(x) deposition on an equivalent CrO(x) monolayer on alumina and deposition of CrO(x) on an equivalent monolayer of ...

In situ X-ray absorption spectroscopy (XAS) under reaction conditions of selective propene oxidation was employed to elucidate the local structure of as-prepared and activated molybdenum oxide supported on hollow vapor-grown carbon nanofibers (VGCNF). The local structure of asprepared MoxOy-VGCNF was very similar to that of hexagonal MoO3. During heat treatment in propeneand oxygen-containing a...

Alkene monooxygenase (AMO) from Rhodococcus rhodochrous B-276 is a 3-component enzyme system encoded by the 4-gene operon amoABCD, which catalyzes the stereoselective epoxidation of aliphatic alkenes yielding primarily the R enantiomer. With propene as the substrate, wild-type AMO yields R-epoxypropane with an enantiomeric excess (e.e.) of 83%. The presumed site of alkene oxidation is a dinucle...

Graphene oxides (GOs) may offer extraordinary potential in the design of novel catalytic systems due to the presence of various oxygen functional groups and their unique electronic and structural properties. Using first-principles calculations, we explore the plausible mechanisms for the oxidative dehydrogenation (ODH) of propane to propene by GOs and the diffusion of the surface oxygen-contain...

Photochemical decomposition of 3,3-dimethyldiazirine (DMD) has been computationally investigated by using high-level ab initio calculations in conjunction with the 6-31G and cc-pvdz basis sets. The geometries of minima and transition states, as well as conical intersection points in the seam of crossing of two surfaces, have been optimized with the complete active space self-consistent field (C...

Field measurements were conducted to determine the characteristics of non-methane hydrocarbons (NMHCs) emitted from open burning of wheat straw and maize stover, two major agricultural residues in China. The headfire ignition technique was used with sampling downwind from the agricultural fire. Fifty-two NMHC species were quantified using gas chromatography/mass spectrometry. A carbon mass bala...

Mixed metal bi-component oxide catalysts, including Fe/Mo, U/Mo, U/W, Fe/U, U/V and U/Sb have been prepared, characterised evaluated for gas phase selective toluene oxidation. Selective oxidation activity to form benzaldehyde was exhibited by U/Mo U/W mixed catalysts. The Fe/Mo catalyst produced the highest yield. Catalysts that formed also a range of by-products, these were other partial coupl...