Search results for "Catalysis"

ChemInform Abstract: Inorganic Materials Acting as Heterogeneous Photocatalysts and Catalysts in the Same Reactions

2016

General considerations on the differences and similarities between heterogeneous photocatalysis and thermal catalysis are presented. Some research papers are reviewed where a reaction has been carried out in the presence of an inorganic material used both as catalyst and photocatalyst. The existing literature often compares catalytic reactions undertaken with the contemporaneous presence of radiation, showing only that photocatalytic reactions can occur under milder experimental conditions and at much lower temperatures. Nevertheless, differences in mechanistic aspects, conversions and selectivities between catalytic and photocatalytic reactions should also be highlighted. These are due to …

Book Review: Ions in Solution: Basic Principles of Chemical Interactions. By J. Burgess

1989

Sacrificial Anodes in the Electrocarboxylation of Organic Chlorides

1984

Chromatography. A Science of Discovery. Edited by Robert L. Wixom and Charles W. Gehrke.

2010

Mild Hydrocracking of Vacuum Gasoil over NiMo-Beta Zeolite Catalysts: The Role of the Location of the NiMo Phases and the Crystallite Size of the Zeo…

1998

Abstract Mild hydrocracking composite catalysts based on NiMo/γ-Al2O3-Beta zeolite have been prepared and the influence of the location of the NiMo phases has been studied. A good hydrocracking activity and the highest HDS conversion was found during the hydrocracking of a vacuum gasoil with the composite catalyst where the NiMo is located on the alumina component and then mixed with the zeolite in a proportion of 1 : 1 by weight. The crystal size of the beta zeolite had a significative influence on the catalytic behaviour, being better the smaller the crystallite size is. The small crystallite beta-based catalyst displayed a higher hydrocracking activity than conventional USY and silica-al…

Electrochemical characterization of solid state reaction kinetics using voltammetry of microparticles. Application to thermal decomposition of iron c…

2011

The voltammetry of microparticles is applied to characterize the electrocatalytic ability of solids towards selected electrochemical processes. The variation of catalytic currents under fixed electrochemical conditions permits to obtain composition/time data to be fitted with solid state kinetic models. This methodology is applied to analyze the thermal decomposition of magnesiochromite ferroan and chlorite chromian standards and a South Africa iron chromite ore on the basis of the significant catalytic effect on the electrochemical oxygen evolution reaction (OER) in aqueous alkaline media at mineral-modified graphite electrodes. Measurement of the time variation of catalytic current for OE…

Study of solid state kinetics using voltammetry of immobilized particles. Application to tetragonal to monoclinic transition in nanoparticulate zirco…

2012

Abstract The voltammetry of immobilized particles methodology is applied to study solid state reaction kinetics on the basis of the electrocatalytic ability of solids toward selected electrochemical processes. Measurement of the time variation of catalytic current for oxygen evolution reaction in aqueous alkaline media provides a direct estimate of fractional conversion of the reactant in the course of the reaction for testing different reaction kinetic models. This methodology is applied to analyze the formation of monoclinic zirconia and praseodymia-doped zirconia from tetragonal precursors. Discrimination between competing and successive reactions mechanisms is obtained for reactions inv…

The influence of water and of alkali promotor on the carbon number distribution of fischer-tropsch products formed over iron catalysts

1987

The carbon number distribution of Fischer-Tropsch products formed over an alkalized precipitated iron catalyst has been studied as a function of the water vapor pressure of the synthesis gas. The carbon number distribution of formed hydrocarbons is characterized by a bimodal Schulz-Flory distribution of growth probabilities P1 ≈ 0.6 and P2 ≈ 0.87 attributed to unpromoted and promoted (alkalized) sites on the catalyst surface. Promoted sites are more stable with respect to oxidation (deactivation) by water than unpromoted sites. The growth probability of unpromoted sites decreases with increasing ratio P/P — Studies using Mossbauer spectroscopy have shown that iron foils treated with water c…

Solving Chemical Problems with a Mixture of Quantum-Mechanical and Molecular Mechanics Calculations: Nobel Prize in Chemistry 2013

2013

2020 Roadmap on two-dimensional nanomaterials for environmental catalysis

2019

Abstract Environmental catalysis has drawn a great deal of attention due to its clean ways to produce useful chemicals or carry out some chemical processes. Photocatalysis and electrocatalysis play important roles in these fields. They can decompose and remove organic pollutants from the aqueous environment, and prepare some fine chemicals. Moreover, they also can carry out some important reactions, such as O2 reduction reaction (ORR), O2 evolution reaction (OER), H2 evolution reaction (HER), CO2 reduction reaction (CO2RR), and N2 fixation (NRR). For catalytic reactions, it is the key to develop high-performance catalysts to meet the demand for targeted reactions. In recent years, two-dimen…