scholarly journals Conversion of Methanol on Rutile TiO2 (110) and Tungsten Oxide Clusters: 1. Population of Defect-Dependent Thermal Reaction Pathways

2021 ◽  
Author(s):  
Lars Mohrhusen ◽  
Katharina Al-Shamery
Keyword(s):  
Tungsten Oxide ◽  
Single Crystals ◽  
Model System ◽  
Thermal Reaction ◽  
Reaction Pathways ◽  
Bifunctional Catalysts ◽  
Rutile Tio2 ◽  
Reaction Routes ◽  
And Tungsten

Tungsten oxide clusters deposited on rutile TiO2 (110) single crystals were used as a model system for heterogenous oxide-oxide bifunctional catalysts. The population of different thermal reaction routes in methanol...

scholarly journals Phase-selective active sites on ordered/disordered titanium dioxide enable exceptional photocatalytic ammonia synthesis

2021 ◽  
Author(s):  
Jinsun Lee ◽  
Xinghui Liu ◽  
Ashwani Kumar ◽  
Yosep Hwang ◽  
Eunji Lee ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Active Sites ◽  
Rational Design ◽  
Ammonia Synthesis ◽  
Reduction Reaction ◽  
Band Structures ◽  
Electronic Band ◽  
Defect Sites ◽  
Electronic Band Structures ◽  
Reaction Routes

This work highlights the importance of a rational design for more energetically suitable nitrogen reduction reaction routes and mechanisms by regulating the electronic band structures with phase-selective defect sites.

scholarly journals A Study on the Effect of Alumina on the Morphology and Reduction Behavior of Sinter by In Situ Observation

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 740
Author(s):  
Sang Gyun Shin ◽  
Wan Ho Kim ◽  
Dong Joon Min
Keyword(s):  
Reduction Rate ◽  
Al2o3 Content ◽  
Confocal Laser ◽  
In Situ Observation ◽  
Sintering Process ◽  
Reduction Behavior ◽  
Reducing Gas ◽  
Interfacial Chemical Reaction ◽  
Reaction Routes

The effects of Al2O3 content on the morphology and reducibility of sinter were respectively investigated using confocal laser microscopy and thermogravimetric analysis at 1273 K under CO gas. To understand the effects of the sintering process, separate samples were prepared via the equilibrium and metastable reaction routes. In the equilibrium samples, the addition of Al2O3 led to the formation of the silico-ferrite of calcium and alumino phase and a decrease in the reduction rate due to the lowered reactivity of iron oxide. In contrast, in the metastable samples, the reduction rate increased after the addition of 2.5 mass% Al2O3. The addition of Al2O3 decreased the fraction of the liquid phase and increased the fraction of pores in the sample. As a result, the reduction rate is proportional to the Al2O3 content owing to the changes in the sinter morphology. In determining the reduction rate of the sinter, the influence of the microstructure on the diffusion of the reducing gas is more significant than that of the interfacial chemical reaction due to the formation of the SFCA phase. The microstructure changes of the sinter with the addition of Al2O3 and the corresponding reduction behaviors are further discussed.

Thermochemical Evaluation of Hydroxyl and Peroxyl Radical Precursors in the Formation of Tropospheric Ozone Reactions

2010 ◽  
Vol 3 ◽  
pp. 74-83
Author(s):  
G.O. Umosekhaimhe ◽  
S.E. Umukoro
Keyword(s):  
Particulate Matter ◽  
Tropospheric Ozone ◽  
Chemical Species ◽  
Basis Set ◽  
Enthalpies Of Formation ◽  
Ozone Formation ◽  
Complete Basis Set ◽  
Equilibrium Analyses ◽  
No2 Formation ◽  
Reaction Routes

The thermochemical properties of varieties of species needed to assess the most prominent pathways of tropospheric ozone transformation have been established. In the troposphere, ozone which is a secondary pollution produced by photochemical induced transformation, acts as an oxidizing agent to numerous atmospheric reactions leading to the formation of particulate matter. Based on the climate related problems resulting from the precursor of particulate matter, it is adequate to establish the feasible routes of ozone formation. In this study, the electronic structure methods which approximate the Schrödinger equation to compute Gibbs free energies and enthalpies of formation of the various chemical species participating in the reactions were used. These thermodynamic properties were determined using four computational model chemistry methods integrated in the Gaussian 03 (G03) chemistry package. Five known reaction pathways for the formation of NO2 (the O3 precursor specie), as well as the dominant ozone formation route from NO2 were examined and their energies determined. Of all the computational methods, the complete basis set (CBS-4M) method produced energies for all species of the five reaction routes. Out of the five routes, only the reactions involving radical species were favoured to completion over a temperature range of -100 and +100oC. The most relevant reaction route for the formation of NO2 and subsequently O3 is that involving the peroxyl acetyl nitrate (PAN) and hydroxyl radicals. Chemical equilibrium analyses of the reaction routes also indicated that reduction in temperature encourages NO2 formation while increase in temperature favours O3 production.

scholarly journals Conversion of jet biofuel range hydrocarbons from palm oil over zeolite hybrid catalyst

2021 ◽  
Vol 11 ◽  
pp. 184798042098153
Author(s):  
Norsahika Mohd Basir ◽  
Norkhalizatul Akmal Mohd Jamil ◽  
Halimaton Hamdan
Keyword(s):  
Palm Oil ◽  
Aromatic Hydrocarbons ◽  
Zeolite Y ◽  
Zeolite Catalysts ◽  
Gas Chromatography Mass Spectrometry ◽  
Chemical Compositions ◽  
Hybrid Catalyst ◽  
X Ray Diffraction ◽  
Temperature Programmed ◽  
Reaction Routes

The catalytic conversion of palm oil was carried out over four zeolite catalysts—Y, ZSM-5, Y-ZSM-5 hybrid, and Y/ZSM-5 composite—to produce jet biofuel with high amount of alkanes and low amount of aromatic hydrocarbons. The zeolite Y-ZSM-5 hybrid catalyst was synthesized using crystalline zeolite Y as the seed for the growth of zeolite ZSM-5. Synthesized zeolite catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, and temperature programmed desorption of ammonia, while the chemical compositions of the jet biofuel were analyzed by gas chromatography-mass spectrometry (GC-MS). The conversion of palm oil over zeolite Y resulted in the highest yield (42 wt%) of jet biofuel: a high selectivity of jet range alkanes (51%) and a low selectivity of jet range aromatic hydrocarbons (25%). Zeolite Y-ZSM-5 hybrid catalyst produced a decreased percentage of jet range alkane (30%) and a significant increase in the selectivity of aromatic hydrocarbons (57%). The highest conversion of palm oil to hydrocarbon compounds was achieved by zeolite Y-ZSM-5 hybrid catalyst (99%), followed by zeolite Y/ZSM-5 composite (96%), zeolite Y (91%), and zeolite ZSM-5 (74%). The reaction routes for converting palm oil to jet biofuel involve deoxygenation of fatty acids into C15–C18 alkanes via decarboxylation and decarbonylation, catalytic cracking into C8–C14 alkanes, and cycloalkanes as well as aromatization into aromatic hydrocarbon.

Cobaltacycles in three oxidation states: redox properties and reaction routes

1987 ◽  
Vol 6 (7) ◽  
pp. 1432-1439 ◽  
Author(s):  
Richard S. Kelly ◽  
William E. Geiger
Keyword(s):  
Redox Properties ◽  
Oxidation States ◽  
Reaction Routes

Anodic behaviour of limonene in low aqueous acetonitrile solutions of Cl−

1988 ◽  
Vol 66 (7) ◽  
pp. 1757-1762 ◽  
Author(s):  
J. A. Caram ◽  
M. E. Martins ◽  
E. G. Gros ◽  
C. M. Marschoff
Keyword(s):  
Water Content ◽  
Aqueous Acetonitrile ◽  
Pt Electrodes ◽  
Acetonitrile Solutions ◽  
Anodic Behaviour ◽  
Derivatives Of ◽  
Reaction Routes

The anodic behaviour of limonene on Pt electrodes was studied in LiCl solutions in acetonitrile with low water content. It was found that cis-6-acetamido-p-menth-1,8-diene is formed with acceptable yields. This compound is of interest as a potential intermediate for obtaining oxidation derivatives of limonene. Other products, among them the new compound 8-acetamido-2,4,8-trimethyl-4-chloromethyl-3-aza-bicyclo[3.3.1]non-2-ene, were identified. Reaction routes are proposed.

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