Assessing solvated electron uptake in low-temperature plasma-exposed solutions as a pathway to quantifying plasma electrons.

Low-temperature plasma (LTP) is being advanced as an alternative radiation source that offers unique chemical properties demonstrated in a variety of reactive plasma species, in which electrons are the primary species derived upon plasma irradiation. We employed a simple and reliable protocol based on two-electron reduction of nitrate into nitrite ions coupled with fluorometric detection to quantify the uptakes of solvated electrons in irradiated solutions under two distinct plasma conditions of our LTP source. In addition, we explored the influence of other plasma species and the solution pH on the uptake rates.

Quantifying hydroxyl radicals generated by a low-temperature plasma using coumarin: methodology and precautions.

The detection and quantification of hydroxyl radicals (HO˙) generated by low-temperature plasmas (LTPs) are crucial for understanding their role in diverse applications of plasma radiation. In this study, the formation of HO˙ in the irradiated aqueous phase is investigated at various plasma parameters, by probing them indirectly using the coumarin molecule. We propose a quantification methodology for these radicals, combining spectrophotometry to study the coumarin reaction with hydroxyl radicals and fluorimetry to evaluate the formation yield of the hydroxylated product, 7-hydroxycoumarin.

New Insights into the Reactivity of Detonation Nanodiamonds during the First Stages of Graphitization.

The present study aims to compare the early stages of graphitization of the same DND source for two annealing atmospheres (primary vacuum, argon at atmospheric pressure) in an identical set-up. DND samples are finely characterized by a combination of complementary techniques (FTIR, Raman, XPS, HR-TEM) to highlight the induced modifications for temperature up to 1100 °C. The annealing atmosphere has a significant impact on the graphitization kinetics with a higher fraction of sp-C formed under vacuum compared to argon for the same temperature.