| 1. |
- Artiglia, Luca, et al.
(författare)
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A surface-stabilized ozonide triggers bromide oxidation at the aqueous solution-vapour interface
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Oxidation of bromide in aqueous environments initiates the formation of molecular halogen compounds, which is important for the global tropospheric ozone budget. In the aqueous bulk, oxidation of bromide by ozone involves a [Br center dot OOO-] complex as intermediate. Here we report liquid jet X-ray photoelectron spectroscopy measurements that provide direct experimental evidence for the ozonide and establish its propensity for the solution-vapour interface. Theoretical calculations support these findings, showing that water stabilizes the ozonide and lowers the energy of the transition state at neutral pH. Kinetic experiments confirm the dominance of the heterogeneous oxidation route established by this precursor at low, atmospherically relevant ozone concentrations. Taken together, our results provide a strong case of different reaction kinetics and mechanisms of reactions occurring at the aqueous phase-vapour interface compared with the bulk aqueous phase.
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| 2. |
- Dey, Ananta, et al.
(författare)
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Hydrogen evolution with hot electrons on a plasmonic-molecular catalyst hybrid system
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Plasmonic systems convert light into electrical charges and heat, mediating catalytic transformations. However, there is ongoing controversy regarding the involvement of hot carriers in the catalytic process. In this study, we demonstrate the direct utilisation of plasmon hot electrons in the hydrogen evolution reaction with visible light. We intentionally assemble a plasmonic nanohybrid system comprising NiO/Au/[Co(1,10-Phenanthrolin-5-amine)2(H2O)2], which is unstable at water thermolysis temperatures. This assembly limits the plasmon thermal contribution while ensuring that hot carriers are the primary contributors to the catalytic process. By combining photoelectrocatalysis with advanced in situ spectroscopies, we can substantiate a reaction mechanism in which plasmon-induced hot electrons play a crucial role. These plasmonic hot electrons are directed into phenanthroline ligands, facilitating the rapid, concerted proton-electron transfer steps essential for hydrogen generation. The catalytic response to light modulation aligns with the distinctive profile of a hot carrier-mediated process, featuring a positive, though non-essential, heat contribution. Direct participation of plasmon-induced hot electrons in the photoelectrocatalytic synthesis of hydrogen. This report solves a long-lasting contentious issue surrounding plasmonic materials on catalytic applications.
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| 3. |
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| 4. |
- Kong, Xiangrui, et al.
(författare)
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Reversibly Physisorbed and Chemisorbed Water on Carboxylic Salt Surfaces under Atmospheric Conditions
- 2020
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:9, s. 5263-5269
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Tidskriftsartikel (refereegranskat)abstract
- Copyright © 2020 American Chemical Society. The particle-gas interface in aerosol systems is of essential importance because it is here that many key atmospheric processes occur. In this study, we employ ambient pressure X-ray photoelectron spectroscopy (APXPS) to investigate the surface properties and processes of an atmospherically relevant carboxylic salt, sodium acetate, at subdeliquescence conditions. From the depth profiles of the elemental ratios of sodium, oxygen, and carbon, we find that after deliquescence-efflorescence cycles the salt surface is sodium-depleted. The mechanism of the observed depletion is proposed to be (i) the formation of neutral acetic acid in the solution due to the nature of the basic salt; (ii) the selective surface enhancement of neutral molecules under aqueous condition; and (iii) a hypothetical kinetic barrier to re-homogenization due to spatial separation and special local conditions on the surface, resulting in varied local surface composition. When the relative humidity gradually increases and approaches the deliquescence point, both reversible water uptake and reversible surface dissociation are confirmed by near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy at the oxygen K-edge and sodium K-edge, respectively. The solvation of sodium requires a higher relative humidity than needed for water adsorption, which suggests that water molecules are taken up by the surface, but the solvation of the salt surface begins only when sufficient water molecules are present, to facilitate the process. The sodium-depleted surface requires additional adsorbed water to affect and dissolve the sodium ions in deeper regions.
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