TY - JOUR

T1 - Influence of the Precursor Structure on the Formation of Tungsten Oxide Polymorphs

AU - Juelsholt, Mikkel

AU - Aalling-Frederiksen, Olivia

AU - Lindahl Christiansen, Troels

AU - Kjær, Emil T.S.

AU - Lefeld, Niels

AU - Kirsch, Andrea

AU - Jensen, Kirsten M.Ø.

N1 - Funding Information: This work is part of a project that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement No. 804066). We furthermore thank DANSCATT (supported by the Danish Agency for Science and Higher Education) for support. We are grateful to the Villum Foundation for financial support through a Villum Young Investigator grant (VKR00015416). We acknowledge the Carlsberg Foundation for financial support through grants CF14-0652 and CF17-0976. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. This research was carried out at beamline P02.1 at PETRA III, and we would like to thank Martin Etter and Alexander Schoekel for assistance in using the beamline. AK gratefully acknowledges the Deutsche Forschungsgemeinschaft (DFG, German science foundation) for funding of the project Ki 2427/1-1 (# 429360100). Publisher Copyright: © 2023 The Authors. Published by American Chemical Society

PY - 2023

Y1 - 2023

N2 - 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, WO3·0.5H2O, 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 suggests that the precursor structure just prior to crystallization can be used as a tool for targeting specific crystalline phases of interest.

AB - 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, WO3·0.5H2O, 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 suggests that the precursor structure just prior to crystallization can be used as a tool for targeting specific crystalline phases of interest.

U2 - 10.1021/acs.inorgchem.3c01659

DO - 10.1021/acs.inorgchem.3c01659

M3 - Journal article

C2 - 37658472

AN - SCOPUS:85171582797

VL - 62

SP - 14949

EP - 14958

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 37

ER -