Plasmas (gas discharges) formed at the surface of liquids can promote a complex mixture of reactions in solution. Here, we decouple two classes of reactions, those initiated by electrons (electrolysis) and those initiated by gaseous neutral species, by examining an atmospheric-pressure microplasma formed in different ambients at the surface of aqueous saline (NaCl) solutions. Electrolytic reactions between plasma electrons and aqueous ions yield an excess of hydroxide ions (OH(-)), making the solution more basic, while reactions between reactive neutral species formed in the plasma phase and the solution lead to nitrous acid (HNO2), nitric acid (HNO3), and hydrogen peroxide (H2O2), making the solution more acidic. The relative importance of either reaction path is quantified by pH measurements, and we find that it depends directly on the composition of the ambient background gas. With a background gas of oxygen or argon, electron transfer reactions yielding excess OH(-) dominate, while HNO2 and HNO3 formed in the plasma and by the dissolution of nitrogen oxide (NOx) species dominate in the case of air and nitrogen. For pure nitrogen (N2) gas, we observe a unique coupling between both reactions, where oxygen (O2) gas formed via water electrolysis reacts in the bulk of the plasma to form NOx, HNO2, and HNO3.
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http://dx.doi.org/10.1021/ja407149y | DOI Listing |
Food Chem
December 2024
Laboratory of Functional Polymers, School of Materials Science and Engineering, Linyi University, Linyi 276005, China. Electronic address:
Organicphosphorus is a ubiquitous pesticide that has potential hazards to human health and environmental well-being. Therefore, the precise identification of residues of organophosphorus pesticides (OPs) emerges as an urgent necessity. A ratiometric fluorescent sensor for the detection of OPs by leveraging the catalytic activities of Ce and Ce on the two fluorescent substrates 4-Methylumbelliferyl phosphate (4-MUP) and o-phenylenediamine (OPD) correspondingly was designed.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States.
Designing catalysts with well-defined active sites with chemical functionality responsive to visible light has significant potential for overcoming scaling relations limiting chemical reactions over heterogeneous catalyst surfaces. Visible light can be leveraged to facilitate the removal of strongly bound species from well-defined single cationic sites (Rh) under mild conditions (323 K) when they are incorporated within a photoactive perovskite oxide (Rh-doped SrTiO). CO, a key intermediate in many chemistries, forms stable geminal dicarbonyl Rh complexes (Rh(CO)), that could act as site blockers or poisons during a catalytic cycle.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Institute of Chemistry, Federal University of Mato Grosso do Sul, Avenida Senador Filinto Muller 1555, Campo Grande, Mato Grosso do Sul 79074-460, Brazil.
There has been huge interest among chemical scientists in the electrochemical reduction of nitrate (NO) to ammonia (NH) due to the useful application of NH in nitrogen fertilizers and fuel. To conduct such a complex reduction reaction, which involves eight electrons and eight protons, one needs to develop high-performance (and stable) electrocatalysts that favor the formation of reaction intermediates that are selective toward ammonia production. In the present study, we developed and applied CoO/graphene nanoribbon (GNR) electrocatalysts with excellent properties for the effective reduction of NO to NH, where NH yield rate of 42.
View Article and Find Full Text PDFInorg Chem
December 2024
Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States.
The nonheme iron(II) complexes containing a fluoride anion, Fe(BNPAO)(F) () and [Fe(BNPAOH)(F)(THF)](BF) (), were synthesized and structurally characterized. Addition of dioxygen to either or led to the formation of a fluoride-bridged, dinuclear iron(III) complex [Fe(BNPAO)(F)(μ-F)] (), which was characterized by single-crystal X-ray diffraction, H NMR, and elemental analysis. An iron(II)(iodide) complex, Fe(BNPAO)(I) (), was prepared and reacted with O to give the mononuclear complex -Fe(BNPAO)(OH)(I) ().
View Article and Find Full Text PDFChemistry
December 2024
University of Copenhagen, Chemistry, Universitetsparken 5, Kemisk Institut, 2100, Copenhagen, DENMARK.
The atmospheric concentration of carbon dioxide (CO2) has fluctuated throughout Earth's history. However, the role of CO2 in prebiotic chemistry has predominantly been limitedly postulated as a C1 precursor, which can be reduced to carbon monoxide or methane mimicking the Wood-Ljungdahl pathway. Herein we present neglected roles of CO2 as an active promoter in accessing biologically important C3-builidng blocks such as lactate, via redox-economic reaction cycles from cyanide (C1) and acetaldehyde (C2).
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