FeHO2
iron oxyhydroxide · goethite, FeO(OH)
FeHO2 is a stable iron-based semiconducting compound widely studied for its effectiveness as a catalyst in oxygen-evolution reactions.
About iron oxyhydroxide
FeHO2 is a thermodynamically stable iron-based oxyhydroxide that functions as a semiconducting material. Its robust structural framework and favorable electronic properties make it a subject of significant interest in the field of electrochemical water splitting and energy conversion technologies. The material is characterized by a high degree of structural diversity, as evidenced by the extensive number of reported crystallographic configurations found in materials databases. This versatility allows it to serve as a reliable platform for developing efficient catalysts for oxygen-evolution reactions. By providing a stable surface for catalytic activity, FeHO2 plays a vital role in advancing sustainable energy storage and production systems.
Key Properties
Cross-validated computational properties for iron oxyhydroxide, aggregated across 5 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of FeHO2. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for FeHO2, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| — | — | 1.61 | 0.0000 | -1.489 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.0000 | -6.989 | 4.24 |
| — | — | 1.64 | 0.0061 | -1.483 | — |
| Cmc21 (No. 36) | orthorhombic | 1.73 | 0.0068 | -6.983 | 3.99 |
| — | — | 1.50 | 0.0102 | -1.479 | — |
| — | — | 1.72 | 0.0147 | -1.474 | — |
| — | — | 1.37 | 0.0181 | -1.471 | — |
| — | — | 1.54 | 0.0232 | -1.466 | — |
| Pmn21 (No. 31) | orthorhombic | 0.00 | 0.0311 | -1.248 | — |
| Cmcm (No. 63) | orthorhombic | 1.24 | 0.0368 | -6.953 | 4.06 |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.0419 | -1.238 | — |
| Pnma (No. 62) | orthorhombic | 0.00 | 0.0419 | -1.238 | — |
Synthesis Routes
Literature-extracted synthesis procedures targeting FeHO2.
Applications
Where iron oxyhydroxide is used.
Frequently Asked Questions
Common questions about iron oxyhydroxide, answered from cross-validated data.
What is FeHO2?
FeHO2 is a stable iron-based semiconducting compound widely studied for its effectiveness as a catalyst in oxygen-evolution reactions.
What is FeHO2 used for?
What is the band gap of FeHO2?
Is FeHO2 a metal, semiconductor, or insulator?
Is FeHO2 thermodynamically stable?
What is the crystal structure of FeHO2?
What is the density of FeHO2?
How many polymorphs of FeHO2 are known?
How is FeHO2 synthesized?
What elements does FeHO2 contain?
Where does the data for FeHO2 come from?
How It Compares
Within the oxide oxygen-evolution catalysts class.
Within the class of oxide oxygen-evolution catalysts, FeHO2 stands out for its unique iron-based composition compared to the more commonly studied nickel- or cobalt-based oxides like NiO or LiCoO2. While many members of this class rely on transition metals like nickel or manganese to facilitate electron transfer, FeHO2 offers a distinct alternative that leverages the earth-abundance and environmental compatibility of iron. It complements complex perovskites like LaMnO3 by providing a simpler, highly stable structural motif that remains competitive in catalytic performance.
Related Compounds
Other Oxide Oxygen-Evolution Catalysts in the database.
Data sources & attribution
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
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