ORCID Profile
0000-0002-2197-2568
Current Organisation
University of Leeds School of Chemical and Process Engineering
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Publisher: American Chemical Society (ACS)
Date: 22-01-2018
Publisher: Wiley
Date: 29-05-2017
Publisher: American Chemical Society (ACS)
Date: 06-2015
Publisher: Wiley
Date: 16-09-2014
Publisher: American Chemical Society (ACS)
Date: 22-06-2020
Publisher: Wiley
Date: 26-02-2014
Abstract: Pair distribution function analysis of in situ total scattering data recorded during formation of WO3 nanocrystals under hydrothermal conditions reveal that a complex precursor structure exists in solution. The WO6 polyhedra of the precursor cluster undergo reorientation before forming the nanocrystal. This reorientation is the critical element in the formation of different hexagonal polymporphs of WO3.
Publisher: International Union of Crystallography (IUCr)
Date: 03-10-2016
DOI: 10.1107/S2053273316012675
Abstract: Varying atomic short-range order is correlated with the ratio of the monoclinic ( m ) to tetragonal ( t ) phase in ZrO 2 nanoparticle formation by solvothermal methods. Reactions from Zr oxynitrate in supercritical methanol and Zr acetate in water (hydrothermal route) were studied in situ by X-ray total scattering. Irrespective of the Zr source and solvent, the structure of the precursor in solution consists of edge-shared tetramer chains. Upon heating, the nearest-neighbor Zr—O and Zr—Zr distances shorten initially while the medium-range connectivity is broken. Depending on the reaction conditions, the disordered intermediate transforms either rapidly into m -ZrO 2 , or more gradually into mixed m - and t -ZrO 2 with a concurrent increase of the shortest Zr—Zr distance. In the hydrothermal case, the structural similarity of the amorphous intermediate and m -ZrO 2 favors the formation of almost phase-pure m -ZrO 2 nanoparticles with a size of 5 nm, considerably smaller than the often-cited critical size below which the tetragonal is assumed to be favoured. Pair distribution function analysis thus unravels ZrO 2 phase formation on the atomic scale and in this way provides a major step towards understanding polymorphism of ZrO 2 beyond empirical approaches.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Dipankar Saha.