In recent years, nanocrystals of metal sulfide materials have attracted scientific research interest for renewable energy applications due to the abundant choice of materials with easily tunable electronic, optical, physical and chemical properties. Metal sulfides are semiconducting compounds where sulfur is an anion associated with a metal cation; and the metal ions may be in mono-, bi- or multi-form. The diverse range of available metal sulfide materials offers a unique platform to construct a large number of potential materials that demonstrate exotic chemical, physical and electronic phenomena and novel functional properties and applications. To fully exploit the potential of these fascinating materials, scalable methods for the preparation of low-cost metal sulfides, heterostructures, and hybrids of high quality must be developed. This comprehensive review indicates approaches for the controlled fabrication of metal sulfides and subsequently delivers an overview of recent progress in tuning the chemical, physical, optical and nano- and micro-structural properties of metal sulfide nanocrystals using a range of material fabrication methods. For hydrogen energy production, three major approaches are discussed in detail: electrocatalytic hydrogen generation, powder photocatalytic hydrogen generation and photoelectrochemical water splitting. A variety of strategies such as structural tuning, composition control, doping, hybrid structures, heterostructures, defect control, temperature effects and porosity effects on metal sulfide nanocrystals are discussed and how they are exploited to enhance performance and develop future energy materials. From this literature survey, energy conversion currently relies on a limited range of metal sulfides and their composites, and several metal sulfides are immature in terms of their dissolution, photocorrosion and long-term durability in electrolytes during water splitting. Future research directions for innovative metal sulfides should be closely allied to energy and environmental issues, along with their advanced characterization, and developing new classes of metal sulfide materials with well-defined fabrication methods.

Recent advances in metal sulfides: from controlled fabrication to electrocatalytic, photocatalytic and photoelectrochemical water splitting and beyond

Iron disulfide for solar energy conversion

Iron pyrite (cubic FeS 2 ) is a promising candidate absorber material for earth-abundant thin-fi lm solar cells. In this report, single-phase, large-grain, and uniform polycrystalline pyrite thin fi lms are fabricated on glass and molybdenum-coated glass substrates by atmospheric-pressure chemical vapor deposition (AP-CVD) using the reaction of iron(III) acetylacetonate and tert -butyl disulfi de in argon at 300 ° C, followed by sulfur annealing at 500‐550 ° C to convert marcasite impurities to pyrite. The pyrite-marcasite phase composition depends strongly on the concentration of sodium in the growth substrate and the sulfur partial pressure during annealing. Phase and elemental composition of the fi lms are characterized by X-ray diffraction, Raman spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, Rutherford backscattering spectrometry, and X-ray photoelectron spectroscopy. The in-plane electrical properties are surprisingly insensitive to phase and elemental impurities, with all fi lms showing p -type, thermally activated transport with a small activation energy ( ≈ 30 meV), a roomtemperature resistivity of ≈ 1 Ω cm, and low mobility. These ubiquitous electrical properties may result from robust surface effects. These CVD pyrite thin fi lms are well suited to fundamental electrical studies and the fabrication of pyrite photovoltaic device stacks.

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Atmospheric‐Pressure Chemical Vapor Deposition of Iron Pyrite Thin Films

Iron pyrite (cubic FeS2) is a promising candidate absorber material for earth-abundant thin-film solar cells. Here, we report on phase-pure, large-grain, and uniform polycrystalline pyrite films that are fabricated by solution-phase deposition of an iron(III) acetylacetonate molecular ink followed by sequential annealing in air, H2S, and sulfur gas at temperatures up to 550 °C. Phase and elemental compositions of the films are characterized by conventional and synchrotron X-ray diffraction, Raman spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, and X-ray photoelectron spectroscopy (XPS). These solution-deposited films have more oxygen and alkalis, less carbon and hydrogen, and smaller optical band gaps (Eg = 0.87 ± 0.05 eV) than similar films made by chemical vapor deposition. XPS is used to assess the chemical composition of the film surface before and after exposure to air and immersion in water to remove surface contaminants. Optical measurements of films rich in marcasite (o...

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Iron Pyrite Thin Films Synthesized from an Fe(acac)3 Ink

FeS2 and (Fe,Co)S2 thin films prepared by magnetron sputtering have been investigated as model catalysts for the oxygen reduction reaction (ORR), and their activities were compared against that of a sputtered thin film of Pt. Scanning Auger microscopy (SAM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and micro-Raman spectroscopy have been used, in parallel with electrochemical activity measurements using the thin film as a rotating disk electrode (RDE), to assess how the electrochemical performances of the sulfide films relate to chemical composition and structure. Comparisons were also made against a mineral FeS2 pyrite whose open circuit potential (OCP) was 0.62 V and much less than the values of 0.78 and 0.80 V found for the FeS2 and (Fe,Co)S2 thin films, respectively (all potentials are given vs the reversible hydrogen electrode). There are indications that the ORR activities for these films may be associated with the presence of some p...

Characterization of FeS2-Based Thin Films as Model Catalysts for the Oxygen Reduction Reaction

Thin pyrite (FeS2) films prepared by magnetron sputtering

https://doi.org/10.1016/j.mex.2022.101823

R. Dasbach

Papers

Thin pyrite (FeS2) films prepared by magnetron sputtering

Analysis of sugar crystal size in honey