Thin films of nanocrystalline and porous FeS(2) with marcasite phase have been deposited from a greenish-blue iron nitroprusside precursor film, which readily gives FeS(2) on reacting with an aqueous solution of sodium sulfide. High resolution X-ray diffraction (HRXRD) pattern indicated the formation of polycrystalline and orthorhombic (marcasite) phase of FeS(2), whereas the field emission scanning electron microscopy (FESEM) showed the morphology of the films to be consisted of grains of average 25 nm diameter with unevenly distributed numerous pores. Optical characterization (UV-Vis and photoluminescence) revealed significant amount of blueshift in the band gap energy of the deposited material, which is attributed to the strong quantum confinement effect exerted by the FeS(2) nanocrystals. The deposited FeS(2) films showed good photocatalytic activity toward the degradation of Rose Bengal dye and could be found efficient for wastewater treatment.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.jcis.2012.10.049 | DOI Listing |
Chemistry
June 2024
The Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, 20015, U.S.A.
In this study, we conduct extensive high-pressure experiments to investigate phase stability in the cobalt-nitrogen system. Through a combination of synthesis in a laser-heated diamond anvil cell, first-principles calculations, Raman spectroscopy, and single-crystal X-ray diffraction, we establish the stability fields of known high-pressure phases, hexagonal NiAs-type CoN, and marcasite-type CoN within the pressure range of 50-90 GPa. We synthesize and characterize previously unknown nitrides, CoN, Pnma-CoN and two polynitrides, CoN and CoN, within the pressure range of 90-120 GPa.
View Article and Find Full Text PDFEnviron Sci Process Impacts
March 2024
Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
Mercury-bearing nano-mineral assemblages (Hg-NMAs) are chemically and mineralogically heterogeneous, micrometer-sized aggregates of nanoparticles (NPs) found in contaminated soils and sediments. Although these NMAs control sequestration and release of Hg that is a global contaminant, our understanding is limited with respect to the conditions of different types of Hg-NMAs, the diversity of its minerals, the size distribution of its NPs and whether mineral replacement and alteration reactions in these NMAs result in the release of Hg-bearing NPs. For this purpose, Hg-NMAs in four sediment samples from the Guanajuato Mining District (GMD) in Mexico, a region that was polluted by Hg and silver (Ag) due to historical mining involving Hg amalgamation, are characterized at the micro- and nanoscale.
View Article and Find Full Text PDFNanoscale Horiz
September 2023
Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.
Techniques are well established for the control of nanoparticle shape and size in colloidal synthesis, but very little is understood about precursor interactions and their effects on the resultant crystalline phase. Here we show that oleate, a surface stabilizing ligand that is ubiquitous in nanocrystal synthesis, plays a large role in the mechanism of phase selection of various metal sulfide nanoparticles when thiourea is used as the sulfur source. Gas and solid-phase FTIR, C, and H NMR studies revealed that oleate and thiourea interact to produce oleamide which promotes the isomeric shift of thiourea into ammonium thiocyanate, a less reactive sulfur reagent.
View Article and Find Full Text PDFInorg Chem
August 2023
Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark.
The Sb compounds with = Cr, Fe, Ru, and Os have been investigated under high pressures by synchrotron powder X-ray diffraction. All compounds, except CrSb, were found to retain the marcasite structure up to the highest pressures (more than 50 GPa). In contrast, we found that CrSb has a structural phase transition around 10 GPa to a metastable, MoP-type structure with Cr coordinated to seven Sb atoms.
View Article and Find Full Text PDFRSC Adv
November 2022
Laboratório de Síntese e Caracterização de nanoMateriais - Departamento de Física, Universidade Federal de Santa Catarina 88040-900 Florianópolis SC Brazil
The mechanochemical synthesis of all cobalt tellurides' phases is demonstrated in this work. The samples had their structural, microstructural, and magnetic characterizations performed by X-ray powder diffraction, transmission electron microscopy, and magnetometry techniques. The initial atomic stoichiometries tested of CoTe and CoTe resulted in the synthesis of the γ-CoTe (marcasite), α-CoTe 3̄ (pyrite), α-CoTe 3̄1 (CdI-like), and β-CoTe 6/ phases with different weight proportions in the sample.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!