Elementary reaction

About: Elementary reaction is a research topic. Over the lifetime, 2972 publications have been published within this topic receiving 76110 citations.

A Direct Study of the Reactions of CH2 (X̃ 3B1)-Radicals with Selected Hydrocarbons in the Temperature Range 296 K ≤ T ≤ 705 K

Abstract: The kinetics of the reactions of CH2 (X 3B1)-radicals with five selected organic compounds has been studied in an isothermal discharge flow system in the temperature range 296 K ≤ T ≤ 705 K. Ground state CH2-radicals have been generated via the reaction O + CH2CO and monitored with a far infrared laser magnetic resonance spectrometer. The experimental results are described by the following Arrhenius expressions: Two basic reaction mechanisms, either direct H-atom abstraction by 3CH2 or thermal excitation of 3CH2 to the low lying a 1A1 state followed by consecutive reactions of 1CH2, are of importance. For acetaldehyde, isobutane, and propane direct H-atom abstraction by 3CH2 predominates. After separation of the small contribution attributed to the singlet reaction the following rate constants for the reactions of CH2 (X3B1) with acetaldehyde, isobutane, and propane are obtained: Presuming the reactions of 1CH2 with hydrocarbons are fast the thermal excitation mechanism dominates the reaction system in the cases of methane and ethane. The activation energy of EA (CH4) = 40 ± 8 kJ/mol measured for methane is concluded to he determined by the singlet-triplet energy splitting in CH2.

Motivated surface reaction thermodynamics on the bismuth oxyhalides with lattice strain for enhanced photocatalytic NO oxidation

Abstract: Understanding and establishing a specific relationship between modified structures and photocatalytic reaction process has a profound significance for designing catalysts with preferable activity. In this study, we have favorably synthesized the bismuth oxyhalides (BiOClxBr1-x, 0 ≤ x ≤ 1) photocatalysts by utilizing the ethylene glycol assisted solvothermal method and the calcination procedure for photocatalytic nitric oxide oxidation. By regulating the halogen proportion in anions layer, the lattice strain has been induced in the structure, specifically the tensile strain in c axis. By virtue of in situ DRIFTS and DFT calculation, we found that the optimized surface reaction thermodynamic process should be the main factors response for prominent enhanced photocatalytic activity, rather than the light absorption and separation of carriers. The bismuth oxyhalides with Cl/Br ratios of 3:1 (BiOClxBr1-x-3:1) possess the lowest thermodynamic energy barrier for photocatalytic nitric oxide oxidation reaction, whilst both associative and dissociative reaction process exist in the initial elementary reaction about oxygen reduction. Finally, we develop a feasible strategy to depress thermodynamic energy barriers via tuning the ratio of halogen in anions layer and bringing the lattice strain, as well build relationship between the adjusted structures and surface reaction process.