Abstract
Pyrite (FeS2) nanocrystals with a narrow size distribution and optical absorption from 1600 to 380 nm were synthesized in a single stage by reacting ferrous chloride with elemental sulfur in oleylamine (OAm) without an additional ligand. X-ray diffraction, Raman, and scanning electron microscopy showed that pyrite cubes with dimensions of 88 ± 14 nm formed at 200 C, an S to Fe ratio of 6, and 1 h reaction time in OAm. The time required to form phase pure pyrite depended on the S to Fe ratio. Phase purity was obtained in less than 1 h at a ratio of 6, but times as long as 24 h were necessary at a ratio of 2.75. The rate of pyrite formation increased with higher sulfur concentrations, which shows that molecules containing sulfur are involved in the rate-determining step. Both H2S and polysulfides of the form Sn2- are known to form in oleylamine. The slow step is the reaction between FeS and these molecules. Fe2+S2- undergoes nucleophilic attack by H2S and Sn2-; S2- converts to S- and sulfur is transferred forming pyrite Fe2+S22-.
Original language | English (US) |
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Pages (from-to) | 3565-3572 |
Number of pages | 8 |
Journal | Crystal Growth and Design |
Volume | 15 |
Issue number | 8 |
DOIs | |
State | Published - Aug 5 2015 |
ASJC Scopus subject areas
- General Chemistry
- General Materials Science
- Condensed Matter Physics