Nanoparticles are important catalysts for many chemical transformations. However, owing to their structural dispersions, heterogeneous distribution of surface sites and surface restructuring dynamics, nanoparticles are intrinsically heterogeneous and challenging to characterize in ensemble measurements. Using a single-nanoparticle single-turnover approach, we study the redox catalysis of indivi...

The autoignition of the catalytic reaction of hydrogen/air mixtures on thin palladium wires is analyzed in this paper. The reduced heterogeneous kinetics is modeled with a mechanism that includes the dissociative adsorption of both reactants, together with three surface reactions of the Langmuir–Hinshelwood type, and the desorption reaction of the adsorbed product, H2O(s). We show that for the ...

The photocatalytic degradation of phenol in aqueous suspensions of TiO2 under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The ...

Producing a definitive picture of the CO oxidation reaction (CO + O2 ? CO2) on Pt-group metals (Rh, Pd, Pt, and Ru) across the ‘pressure gap’ has proved to be a challenging task. Surface-sensitive techniques amenable to high pressure environments (e.g. PM-IRAS) have sparked a renewed interest in this reaction under realistic pressures. Here, we review recent work in our laboratory examining CO ...

The mechanism of the CO oxidation promoted by a neutral Ag(55) cluster was investigated extensively, using density functional theory calculations. The CO oxidation process catalyzed by anionic and cationic Ag(55) clusters was also studied, to clarify the effects of the charge state. The Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms were discussed in detail. Six reaction pathways wer...

Adsorption of environmentally important aromatic molecules on a water surface is studied by means of classical and ab initio molecular dynamics simulations and by reflection-absorption infrared spectroscopy. Both techniques show strong activity and orientational preference of these molecules at the surface. Benzene and naphthalene, which bind weakly to water surface with a significant contribut...

TiO2-coated porous silica glass tubes containing macropores were fabricated and evaluated for their water-purification capacity using aqueous solutions of methylene blue. From the results of photocatalytic degradation tests at different initial methylene blue concentrations, the equilibrium adsorption constant (K) was determined to be 4.6 × 10−2 L μmol−1, and the Langmuir-Hinshelwood rate const...

Palladium supported Al2O3 and SiO2 catalysts have been synthesized and evaluated for carbon monoxide oxidation in the presence of ozone. The factors affecting the CO oxidation such as Pd loading (wt%), contact time, reaction temperature and O3/CO molar ratio have been studied. The extent of ozone decomposition on Pd catalysts is proportional to the CO oxidation activity. High reaction temperatu...

Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-Al2O3 supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate...

Air pollution by nitrogen oxides represents a serious environmental problem in urban areas where numerous sources of these pollutants are concentrated. One approach to reduce the concentration of these air pollutants is their light-induced oxidation in the presence of molecular oxygen and a photocatalytically active building material which uses titanium dioxide as the photocatalyst. Herein, res...