Nitrogen adsorption and desorption at iron pyrite FeS2{100} surfaces

Liu, Tao; Temprano, Israel; Jenkins, Stephen J.; King, David A.; Driver, S.M.

doi:10.1039/c2cp41549f

Cited by 18 publications

(35 citation statements)

References 39 publications

(43 reference statements)

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“…The cleanliness and surface order were monitored by AES, TPD, and LEED . The experimental apparatus and the cleaning procedure for the Ni{110} crystal has been described in detail elsewhere [29][30][31][32].…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Increased thermal stability of activated N₂adsorbed on K-promoted Ni{110}

Liu

Temprano

Jenkins

2017

Phys. Chem. Chem. Phys.

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Industrial synthesis of ammonia takes place at high temperatures and pressures via the dissociative adsorption of molecular nitrogen on a transition metal catalyst. In contrast, biological ammonia synthesis occurs under ambient conditions via the hydrogenation of intact molecular nitrogen at the active site of an enzyme. We hypothesise that the latter process may be mimicked within an inorganic system if the intact nitrogen molecule can be polarised, rendering it particularly susceptible to attack by hydrogen. Furthermore, by analogy with the surface chemistry of carbon monoxide at alkali-modified nickel and cobalt surfaces, we consider whether such a polarisation may be achieved by coadsorption with potassium on the same or similar transition metals. Here, we report on reflection absorption infrared spectroscopy results, interpreted with the aid of first-principles density functional calculations, which reveal both similarities and differences between the behaviour of carbon monoxide and nitrogen. Importantly, our calculations suggest that the surface-induced dipole of molecular nitrogen can indeed be enhanced by the coadsorbed alkali metal.

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Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Increased thermal stability of activated N₂adsorbed on K-promoted Ni{110}

Liu

Temprano

Jenkins

2017

Phys. Chem. Chem. Phys.

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“…In order to establish the chemistry of iron sulphide towards ammonia synthesis from atmospheric nitrogen and hydrogen, the reactivity of FeS2{100} towards N2 and H2 gas adsorption was studied before turning to co-adsorption experiments. Here we present a summary of our work, some of it previously published [24,25] but described here with additional detail, on the adsorption characteristics and reaction upon coadsorption of these species on clean FeS2{100}. We also present preliminary work on biomimetic approaches to improve the characteristics of this material towards the activation of adsorbed N2.…”

Section: Adsorption and Reaction Of Nitrogen On Clean Fes2{100}mentioning

confidence: 99%

“…In this article we report a systematic study of the activity of naturally grown pyrite towards the hydrogenation of adsorbed nitrogen species. We review the adsorption of N2, and H2 using as-grown FeS2{100} as model material, as well as the formation of ammonia under ultra-high vacuum (UHV) conditions, some of which has been published in detail elsewhere [24,25]. These fundamental steps are the key to evaluate the kinetics of the formation of ammonia, and have been thoroughly studied and debated in the context of the Haber-Bosch process.…”

Section: Introductionmentioning

confidence: 99%

Activity of iron pyrite towards low-temperature ammonia production

2017

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In this work we report the characteristics of iron pyrite toward the production of ammonia at low temperatures under ultra-high vacuum conditions. We review (with additional unpublished details) our previous systematic study of nitrogen and hydrogen adsorption on single-crystal iron pyrite (FeS2) and summarise our earlier findings regarding the possibility of ammonia synthesis on this material. We also present new results concerning the adsorption of nitrogen and hydrogen on two related materials, namely molybdenum-treated iron pyrite surfaces and iron pyrite nanostructures deposited on a gold single-crystal. On the bare iron pyrite samples, ammonia is produced upon hydrogenation of preadsorbed N species at 230 K, demonstrating that all hydrogenation steps are possible at low pressures and temperatures. Nitrogen adsorbs molecularly on FeS2{100} at low temperatures, desorbing at 130 K, but does not adsorb dissociatively even at pressures up to 1 bar. Adsorbed nitrogen species can, however, be obtained through exposure to excited nitrogen species. Hydrogen adsorbs on FeS2{100}, but only in the presence of an incandescent Ta filament. Recombinative desorption of H2 occurs at 225 K and is accompanied by desorption of H2S at 260 K. On the molybdenum-treated iron-pyrite, no appreciable Nads species were detected under the experimental conditions studied, and the same is true for iron pyrite nanostructures on Au{111}. We also provide further details of our efficient and reproducible method for preparing wellordered stoichiometrically pure FeS2{100} suitable for surface science studies.

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“…Dry nitrogen is used at NASA Johnson Space Center for storage of the Antarctic Meteorite Collection (Dr. Kevin Righter, curator, personal communication). Nitrogen gas (N 2 ) will not dissociate to adsorb to the pyrite surface (Liu et al, 2012). Archival plastics mentioned above have similar order-of-magnitude diffusivities for oxygen, nitrogen, and argon (McKeen, 2017), but N 2 is almost always the lowest diffusivity molecule.…”

Section: Interventions III -Aciditymentioning

confidence: 99%

A review of “pyrite disease” for paleontologists, with potential focused interventions

Tacker¹

2020

Palaeontol Electron

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A literature review of the chemical reactions involved in pyrite oxidation/hydration ("pyrite disease") in geological or fossil collections gives direction to a suite of focused interventions. Reactions on the pyrite surface lie at the heart of the chemical process, accompanied by the movement of electrons on and through the pyrite semiconductor. Control of these electrons ultimately may be futile, but examination of the reactions at the atomic level leads to new possibilities for treatment, and identifies why some treatments are ineffective. This review also identifies gaps in our understanding of the oxidation and hydration reactions. Fossil biomaterials-bone or shell-often contain or are partially replaced by pyrite. Acidity produced by pyrite decay destroys these materials. Older treatments focus on acid neutralization, and humidity control as solutions for megascopic problems. Focused interventions target specific steps in the chemical reactions at the atomic scale. Interventions are informed by identification of all the minerals participating in the process, and accurate characterization of the bone, pyrite and sedimentary matrix. Bone minerals and pyrite are structurally and chemically heterogeneous, so each intervention requires bench testing, complimented by analytical measurements. Chemically passivating the unreacted pyrite surface shows the greatest promise. Anticipation of a new specimen's susceptibility to decay is key. Decay may be accelerated using techniques of humidity buffering with saturated salt solutions. Conductivity of pyrite (which varies over four orders of magnitude) may be measured. A database of pyrite conductivity is highly desirable.

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Nitrogen adsorption and desorption at iron pyrite FeS2{100} surfaces

Cited by 18 publications

References 39 publications

Increased thermal stability of activated N₂adsorbed on K-promoted Ni{110}

Increased thermal stability of activated N₂adsorbed on K-promoted Ni{110}

Activity of iron pyrite towards low-temperature ammonia production

A review of “pyrite disease” for paleontologists, with potential focused interventions

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Nitrogen adsorption and desorption at iron pyrite FeS2{100} surfaces

Cited by 18 publications

References 39 publications

Increased thermal stability of activated N2adsorbed on K-promoted Ni{110}

Increased thermal stability of activated N2adsorbed on K-promoted Ni{110}

Activity of iron pyrite towards low-temperature ammonia production

A review of “pyrite disease” for paleontologists, with potential focused interventions

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Product

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Increased thermal stability of activated N₂adsorbed on K-promoted Ni{110}

Increased thermal stability of activated N₂adsorbed on K-promoted Ni{110}