Nitrate reductase activity from filamentous, heterocyst-forming cyanobacteria showed a biphasic kinetic behavior with respect to nitrate as the variable substrate. Two kinetic components were detected, the first showing a higher affinity for nitrate (K(m), 0.05-0.25 mm) and a lower catalytic activity and the second showing a lower affinity for nitrate (K(m), 5-25 mm) and a higher (3- to 5-fold)...

Methanol is a hydrogen carrier for fuel cells and its chemical transformations are of great current interest. Methanol oxidation by vanadium oxides is well studied, hence, serves as a good measure for catalytic activity. Arrays of VO2 nanowires grown on r-cut sapphire prove to be unique for the in situ catalytic activity tests. Here, we present size and morphology dependent activity of Platinum...

Creation of synthetic catalysts with enzyme-like behavior is challenging despite strong interest in such systems. Extraction of tetrachloroaurate into the hydrophilic core of an interfacially cross-linked reverse micelle (ICRM) produced an artificial "metalloenzyme" with highly unusual catalytic properties. The ICRM pulled the substrate toward the catalytic metal, which converted it efficiently...

This paper presents a mean-value model describing the SCR system of a heavy duty mobile application. The system consists of two catalysts, one for the preoxidation and one for the selective catalytic reduction (SCR) of NOx. The model of the catalytic converter system is one-dimensional. Its core consists of three identical cells that describe the thermal and the chemical behavior of the SCR cat...

A series of water-soluble (NHC)Pt(0)(dvtms) and (NHC)Pt(0)(AE) complexes containing different sulfonated NHC ligands (dvtms = divinyltetramethyldisiloxane and AE = diallyl ether) are reported. The dvtms compounds have been found to be quite robust and to display some conformational rigidity, whereas their AE counterparts are less stable and more flexible. The catalytic evaluation of these compl...

A bifunctional covalent organic framework (COF) has been illustrated in the context of partial metalation of a highly porous and chemically robust pyridine containing COF (COF-TpPa-Py) with Pd species and by taking advantage of the base catalytic behavior of pyridine. The resultant bifunctionalized COF exhibits excellent performance in catalyzing one-pot cascade aerobic oxidation–Knoevenagel co...

Density functional theory (DFT)-based calculations were carried out to predict the geometry, energy and electronic structures of the small bimetallic AumPtn (2 ≤m + n≤ 4) clusters deposited on a single-wall (5,5)-carbon nanotube (CNT). The chemical reactivity of these supported bimetallic clusters towards O2 reduction reaction was also considered. The calculations indicate that Au atoms tend to...

This paper describes a catalytic theory that grounds cognition in biology. An enzyme is a biological catalyst that increases the speed of a molecular reaction; the reaction is thought to occur via a traveling wave, a soliton, whose formation and persistence depend on the structure or invariance of the catalytic environment. Generalizing to cognition, the invariance of perceptual events plays th...

Copper(ii) and palladium(ii) meso-tetraferrocenylporphyrins ( and ) were employed as catalysts for electrochemical proton reduction in DMF using trifluoroacetic acid (TFA) or triethylamine hydrochloride (TEAHCl) as acids. Gas analysis under electrocatalytic conditions at a glassy carbon working electrode confirmed the product as H2. showed catalytic behavior for both TFA and TEAHCl, whereas onl...

background: toluene is a volatile organic compound, one of 189 hazardous air pollutants (hap s ) and the most important pollutant found in most industries and indoor environments; owing to its adverse health, toluene must be treated before being released into the environment. methods : in this research study, a continuous-flow system (including an air compressor, silica gel filters and activate...