The oxidation of methanol over highly dispersed vanadia supported on TiO2 (anatase) has been investigated using in situ Fourier transform infrared spectroscopy (FTIR), near ambient pressure X-ray photoelectron spectroscopy (NAP XPS), X-ray absorption near-edge structure (XANES), and a temperature-programmed reaction technique. The data were complemented by kinetic measurements collected in a fl...

The kinetics of methane combustion at low temperatures are consistent with a Mars–van Krevelen redox mechanism involving the activation of methane on site pairs consisting of oxygen atoms and oxygen vacancies on the surface of PdOx crystallites. H2O strongly inhibits methane oxidation rates by titrating surface vacancies in a quasi-equilibrated adsorption–desorption step. Initial activation per...

To probe the nature of metal-catalysed processes and to design better metal-based catalysts, atomic scale understanding of catalytic processes is highly desirable. Here we use aberration-corrected environmental transmission electron microscopy to investigate the atomic scale processes of silver-based nanoparticles, which catalyse the oxidation of multi-wall carbon nanotubes. A direct semi-quant...

Introducing a catalyst for dehydrogenation of ethane (EDH) steam cracking represents promising solution with high feasibility to realize efficient ethylene production. We investigated EDH over transition-metal-doped CeO2 catalysts at 873 K in the presence steam. Ce0.8Co0.2O2 exhibited activity and selectivity (ca. 95%). In absence H2O, catalytic dropped rapidly, indicating promotive effect H2O ...

Single-phase powders of LaMnO3 and LaCoO3, lanthanum-based perovskites, were synthesized using the citric acid combustion method. The surface concentration La in obtained powder was higher LaCoO3 than LaMnO3. These samples decomposed 2-naphthol water dark. decomposition reaction is attributed to Mars–van Krevelen (MvK) mechanism because temperature dependence, activation energy, valence change ...

There has been recent interest in the potential of nitrides, hydrides and carbides as novel heterogeneous catalysts for production ammonia a sustainable manner on local scale. It proposed that some these materials can produce via Mars-van Krevelen based mechanistic pathways. Generally, metal-based catalysts, dissociative nitrogen activation is believed to be rate determining step synthesis. How...

By use of operando spectroscopies under cycling reaction conditions, water is shown to hamper the redox dynamics realistic palladium oxide nanoparticles dispersed onto alumina and hydrophobic zeolite supports thereby lowering activity for total oxidation methane. Water adsorption forms hydroxyl ad-species that block methane oxygen dissociation seem prevent lattice take part in oxidation. The ma...

The kinetics of the transformation metallic Fe to active carbide phase at start Fischer–Tropsch (FT) reaction were studied. diffusion rates C atoms going in or out lattice determined using 13C-labeled synthesis gas combination with measurements transient 12C and 13C contents by temperature-programmed hydrogenation. In initial 20 min, diffuses rapidly into occupying thermodynamically very stable...

Positive matrix factorization (PMF) of highresolution laboratory chamber aerosol mass spectra is applied for the first time, the results of which are consistent with molecular level MOVI-HRToF-CIMS aerosolphase and CIMS gas-phase measurements. Secondary organic aerosol was generated by photooxidation of dodecane under low-NOx conditions in the Caltech environmental chamber. The PMF results exhi...