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Title: Non-aqueous metathesis as a general approach to prepare nanodispersed materials: Case study of scheelites

A general approach to the preparation of inorganic nanoparticles is proposed, using metathesis of precursor salts in non-aqueous liquids. Nanoparticles of scheelites AMO{sub 4} (A=Ba, Sr, Ca; M=Mo, W), were obtained with a quantitative yield. Precipitations in formamide, N-methylformamide, propylene carbonate, DMSO and polyols often provide narrow particle size distributions. Advantageous morphology was explained by strong ionic association in non-aqueous solvents, leading to slow nucleation and negligible Ostwald ripening. Mean particle size below 10 nm and high specific surface areas were obtained for several Ca(Sr)Mo(W)O{sub 4} materials, making them promising for applications as adsorbents or catalysts. Zeta-potential of scheelites in aqueous suspensions showed negative values in a wide range of pH. Systematic study of optical properties demonstrated variation of optical gap in the sequences W>Mo and Ba>Sr>Ca. The observed trends were reproduced by DFT calculations. No quantum confinement effect was observed for small particles, though the surface states induce low-energy features in the optical spectra. - Graphical abstract: Scheelites AMO{sub 4} (A=Ca, Sr, Ba; M=Mo, W) were prepared in various non-aqueous liquids with high specific surface areas and narrow size distributions. The optical gap of scheelites changes in the series Ca
Authors:
Publication Date:
OSTI Identifier:
22486757
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 229; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORBENTS; BARIUM COMPOUNDS; CALCIUM COMPOUNDS; CARBONIC ACID ESTERS; CATALYSTS; DENSITY FUNCTIONAL METHOD; DMSO; FORMAMIDE; MOLYBDATES; MORPHOLOGY; NANOPARTICLES; NUCLEATION; OPTICAL PROPERTIES; PARTICLE SIZE; PH VALUE; SALTS; SPECIFIC SURFACE AREA; STRONTIUM COMPOUNDS; TUNGSTATES