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- Galvez-Martinez, Santos, et al.
(författare)
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Defects on a pyrite(100) surface produce chemical evolution of glycine under inert conditions : experimental and theoretical approaches
- 2019
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 21:44, s. 24535-24542
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Tidskriftsartikel (refereegranskat)abstract
- The presence of non-stoichiometric sites on the pyrite(100) surface makes it a suitable substrate for driving the chemical evolution of the amino acid glycine over time, even under inert conditions. Spectroscopic molecular fingerprints prove a transition process from a zwitterionic species to an anionic species over time on the monosulfide enriched surface. By combining experimental and theoretical approaches, we propose a surface mechanism where the interaction between the amino acid species and the surface will be driven by the quenching of the surface states at Fe sites and favoured by sulfur vacancies. This study demonstrates the potential capability of pyrite to act as a surface catalyst.
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| 2. |
- Mateo-Marti, E., et al.
(författare)
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Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The molecular form of nitrogen, N2, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m 2 of ultraviolet irradiance in the 200–400 nm range. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface.
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