Adsorption of Water, Methanol, and Formic Acid on Fe₂NiP, a Meteoritic Mineral Analogue

Abstract

The surface of an analogue to the meteoritic mineral schreibersite or (Fe,Ni) 3 P was investigated to provide insight into the interaction of the mineral surface with prebiotic molecules such as water, methanol, and formic acid. A protocol for creating synthetic metal-phosphide samples with a surface reflectivity suitable for reflection−absorption infrared spectroscopy (RAIRS) was developed and is outlined in this paper. Scanning electron microscopy coupled with energy dispersive spectroscopy revealed an average defect size less than 1 μm and evidence of subsurface phosphorus segregation. At surface temperatures between 120 and 140 K, RAIRS spectra indicate that water and formic acid interact molecularly with surface atoms, while methanol appears to dissociate into methoxy and protons upon adsorption. The observed infrared spectra provide insight into the adsorption geometries of these prebiotic molecules on synthetic schreibersite. This data suggests the importance of the schreibersite mineral surface in aqueous-phase schreibersite-mediated phosphorylation experiments that have been performed by others and strengthens the argument that schreibersite-induced chemistry could occur in astrochemical environments.

Ab Initio Computational Study on Fe2NiP Schreibersite: Bulk and Surface Characterization

“…20 All these experiments clearly show the formation of oxygenated phosphorus compounds, in particular phosphites (HPO3 2-/H2PO3 -), more reactive and soluble than phosphates, and also the phosphorylation of organic compounds, including nucleosides. 18 An accurate study based on RAIRS (Reflection−Absorption InfraRed Spectroscopy) demonstrates that H2O molecules bind preferentially to P atoms on the schreibersite surface at low temperatures (120-140K), 21 this mechanism being also confirmed by isotopically enriched ( 18 O) water. 22 Recently, it has been proven that schreibersite is a good catalyst to also activate the reaction among carbohydrates to give more complex sugars (formose reaction network), accompanied by well-known oxygenated phosphorus species (phosphites and, in minor quantity, phosphates).…”

Systems Astrochemistry: A New Doctrine for Experimental Studies

“…In laboratory investigations of the chemistry occurring within interstellar ices, however, ices are usually deposited onto flat surfaces used for transmission or reflection spectroscopy (e.g., gold, zinc selenide, magnesium fluoride, etc.). Although previous studies have acknowledged that adsorbent morphology may play an important role in the chemistry or spectroscopy of the adsorbate ice (Perets et al, 2007;Gull et al, 2015;Qasim et al, 2017;Wakelam et al, 2017;Pantaleone et al, 2021), there is a scarcity of studies that have considered this experimentally, and fewer still that have considered the chemical influence of the interaction of flat substrates with incident radiation. One study by Mason et al (2008) showed that the infrared spectrum of hexagonal crystalline water ice deposited over soot particles suspended in an ultrasonic trap differed somewhat to that of the same ice deposited onto flat fluoride substrates traditionally used in laboratory astrochemistry.…”

Ab-Initio Computational Study on Fe2NiP Schreibersite: Bulk and Surface Characterization

“…20 All these experiments clearly show the formation of oxygenated phosphorous compounds, in particular phosphites (HPO3 2-/H2PO3 -), more reactive and soluble than phosphates, and also the phosphorylation of organic compounds, including nucleosides. 18 An accurate study based on RAIRS (Reflection−Absorption InfraRed Spectroscopy) demonstrates that H2O molecules bind preferentially P atoms on the schreibersite surface at low temperatures (120-140K), 21 this mechanism being also confirmed by isotopic water- 18 O. 22 Recently, it has been proven that schreibersite is a good catalyst to also activate the reaction among carbohydrates to give more complex sugars (formose reaction network), accompanied by well-known oxygenated phosphorous species (phosphites and, in minor quantity, phosphates).…”