Abstract
The surface oxidation of pyrite can create a (hydr)oxide layer. This configuration constitutes a natural two-semiconductor (tandem) photoelectrochemical cell. Here, we show that an illuminated hematite-pyrite cell produces photocurrent, H2, and O2 by water splitting. Photocurrent is also observed with illumination of hematite alone. The observed current densities are in the same order of magnitude as estimates of banded iron formation deposition rates, and are 400 to 1000 times higher than needed to oxidize, over geologic time, all of the surface water thought to have existed on Mars. Mineral-based water splitting constitutes a potential source of O2 prior to the evolution of oxygenic photosynthesis on Earth. Semiconducting minerals deserve study as photochemical sources of oxidizing power in low-oxygen environments.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
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- The temperature and compositional dependence of disordering in Fe-bearing dolomites
- Quantifying crystallization and devitrification of rhyolites by means of X-ray diffraction and electron microprobe analysis
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- Letter. A natural photoelectrochemical cell for water splitting: Implications for early Earth and Mars
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Articles in the same Issue
- MSA Roebling medal lecture. Mineralogy, petrology, U-Pb geochronology, and geologic evolution of the Dabie-Sulu classic ultrahigh-pressure metamorphic terrane, East-Central China
- Brittle-ductile microfabrics in naturally deformed zircon: Deformation mechanisms and consequences for U-Pb dating
- In situ hot-stage AFM study of the dissolution of the barite (001) surface in water at 30–55 °C
- A multi-domain gem-grade Brazilian apatite
- High-temperature structural behaviors of anhydrous wadsleyite and forsterite
- Rates and mechanism of Y, REE, and Cr diffusion in garnet
- EPR discrimination of microcrystalline calcite geomaterials
- Crystal chemistry of Bi- and Mn-bearing vesuvianite from Långban, Sweden
- Cation ordering in Pb2+-bearing, Mn3+-rich pargasite from Långban, Sweden
- Long-term solid-phase fate of co-precipitated U(VI)-Fe(III) following biological iron reduction by Thermoanaerobacter
- The sulfur speciation in S-bearing minerals: New constraints by a combination of electron microprobe analysis and DFT calculations with special reference to sodalite-group minerals
- Simultaneous sound velocity and density measurements of NaCl at high temperatures and pressures: Application as a primary pressure standard
- The temperature and compositional dependence of disordering in Fe-bearing dolomites
- Quantifying crystallization and devitrification of rhyolites by means of X-ray diffraction and electron microprobe analysis
- Reactions of strontium anorthite with H2O+CaCl2 fluids at 500 °C and high pressure: Kinetic information from in situ synchrotron-radiation XRF analyses of the fluid
- Solubility of xenotime in a 2 M HCl aqueous fluid from 1.2 to 2.6 GPa and 300 to 500 °C
- Elastic and anelastic anomalies due to spin-state transitions in orthorhombic perovskite from isoelectronic behavior of Co3+ and Fe2+
- Accurate determination of ferric iron in garnets by bulk Mössbauer spectroscopy and synchrotron micro-XANES
- Re-investigation of the crystal structure of enstatite under high-pressure conditions
- Second-order P6̄c2-P31c transition and structural crystallography of the cyclosilicate benitoite, BaTiSi3O9, at high pressure
- High-pressure structural studies of eskolaite by means of single-crystal X-ray diffraction
- Almandine: Lattice and non-lattice heat capacity behavior and standard thermodynamic properties
- Witzkeite: A new rare nitrate-sulphate mineral from a guano deposit at Punta de Lobos, Chile
- Krasheninnikovite, KNa2CaMg(SO4)3F, a new mineral from the Tolbachik volcano, Kamchatka, Russia
- Crystal structure of pseudojohannite, with a revised formula, Cu3(OH)2[(UO2)4O4(SO4)2](H2O)12
- Letter. A natural photoelectrochemical cell for water splitting: Implications for early Earth and Mars
- Letter. In situ observation of the breakdown of magnetite (Fe3O4) to Fe4O5 and hematite at high pressures and temperatures
- Letter. The crystal structure of bartelkeite, with a revised chemical formula, PbFeGeVI(Ge2IVO7) (OH)2·H2O, isotypic with high-pressure P21/m lawsonite