Influence of precursor structure on the formation of tungsten oxide polymorphs

11 April 2023, Version 2
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Understanding material nucleation processes is crucial for the development of synthesis pathways for tailormade materials. However, we currently have little knowledge of the influence of the precursor solution structure on the formation pathway of materials. We here use in situ total scattering to show how the precursor solution structure influences which crystal structure is formed during the hydrothermal synthesis of tungsten oxides. We investigate the synthesis of tungsten oxide from the two polyoxometalate salts, ammonium metatungstate and ammonium paratungstate. In both cases, a hexagonal ammonium tungsten bronze (NH4)0.25WO3, is formed as the final product. If the precursor solution contains metatungstate clusters, this phase forms directly in the hydrothermal synthesis. However, if the paratungstate B cluster is present at the time of crystallization, a metastable intermediate phase in the form of a pyrochlore-type tungsten oxide, WO30*5H2O, initially forms. The pyrochlore structure then undergoes a phase transformation into the tungsten bronze phase. Our studies thus experimentally show that the precursor cluster structure present at the moment of crystallization directly influences the formed crystalline phase and suggest that the precursor structure just prior to crystallization can be used as a tool for targeting specific crystalline phases of interest.

Keywords

Nanoparticles
Crystallization
In situ X-ray scattering
Pair Distribution Function analysis

Supplementary materials

Title
Description
Actions
Title
Supporting information for: Influence of precursor structure on the formation of tungsten oxide polymorphs
Description
Additional data and figures.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.