Dispersed-phase Interfaces between Mist Water Particles and Oxygen Plasma Efficiently Produce Singlet Oxygen (¹O₂) and Hydroxyl Radical (•OH)

Abstract

Efficient generation of oxygen radicals and reactive oxygen was successfully performed at the dispersed-phasic interface between vapor-water and oxygen plasma in a reaction chamber having an internal atmosphere with a normal-pressure and temperature. In the space of the reactor chamber (radical vapor reactor [RVR]), the gas phase was strictly controlled in terms of vaporized water (small water mist), temperature, plasma conditions, and UV irradiation. According to spin-trapping electron spin resonance analysis, the RVR efficiently and quantitatively yielded two types of reactive oxygen species ( 1 O 2 and OH radical) with the atmosphere of the RVR chamber. This is the report of the efficient, quantitative production of reactive oxygen in an atmosphere. The reactivity of the produced 1 O 2 and OH radical may be applicable for various chemical processes, such as oxidation and electron absorption.

Sustainable Non‐Thermal Plasma‐Assisted Nitrogen Fixation—Synergistic Catalysis

“…In the gas phase, the plasma-assisted dissociation of nitrogen gas is the first step. [94] The products of the dissociated nitrogen and water molecules could then react via the Zeldovich mechanism, as discussed in Section2.1.1, to form NO x .The formation of gaseous NO x could also be promoted under UV light. On top of this, the photodissociation of N 2 relatedt oU Vi rradiation, or VUV irradiation, also exists, which has been discussed in many studies related to the atmospherics ciences.…”

“…In the gas phase of the gasliquid NTPNF process, vaporized water molecules existed and could be dissociated at the dispersed-phase interface to produce hydroxyl and hydrogen radicals. [94] The products of the dissociated nitrogen and water molecules could then react via the Zeldovich mechanism, as discussed in Section2.1.1, to form NO x .The formation of gaseous NO x could also be promoted under UV light. [95] Another fate for the dissociated nitrogen and water is the reactiont of orm gaseous ammonia.T he reac-tion between the dissociated nitrogen and hydrogen molecules coulde ither be through electronic excitation and ionization, recombination by electrons,o ri on-molecule reactions.…”

Green Surface Cleaning in a Radical Vapor Reactor to Remove Organic Fouling on a Substrate

“…ROS generation by the RVR was shown in a previous report. 21,23 The treatment conditions were ozone injection at 4 L/min, followed by UV irradiation at 185 nm and 254 nm. All reactions in the RVR chamber were performed at 40°C.…”

“…The details of the reaction pathway for producing ROS are described in previous reports. 21,23,[28][29][30][31] 2.4 Surface analysis Surface structural analysis of the substrate was performed by using an AFM, with a PPP-NCHAu probe (42 N/m, Nano World) for imaging. Imaging was carried out in tapping mode and under atmospheric conditions.…”

“…The produced ROS are mainly singlet oxygen ( 1 O 2 ) and hydroxyl radicals (•OH), which were quantitatively obtained in our previous studies. [21][22][23] Ozone and hydrogen peroxide are other types of ROS. These ROS have been used for sterilization and surface treatment because they have high energy and reactivity.…”