Amorphous intermediates and discovery of a kinetic polymorph of BiVO<sub>4</sub> from heating V+Bi+Zn single-source precursors.

Hands, Alexandria E; Barnes, Thomas J; Scarperi, Andrea; Gallant, Benjamin M; Vismara, Emanuele; Wiktor, Julia; Brown, Stephen E; Walker, David et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Molecular single-source precursors are a promising way of obtaining multi-element extended solids directly. We show that thermal decomposition of well-defined mono-, bi- and trimetallic polyoxovanadates (POVs) proceeds through a series of intermediate amorphous and crystalline species which we characterise using solid-state NMR spectroscopy, pair-distribution function (PDF) analysis and in-situ X-ray diffraction, before forming crystalline V<sub>2</sub>O<sub>5</sub> and BiVO<sub>4</sub> products. This synthetic strategy enables the formation of phases inaccessible using other routes, including a previously unknown polymorph of BiVO<sub>4</sub> which we name β-BiVO<sub>4</sub> due to its similarity to β-SnWO<sub>4</sub>. Local structure information also reveals the temperature dependent incorporation of Zn do pants into BiVO<sub>4</sub>. The study also explores the electrochemical properties of amorphous mixed-valence vanadium oxides as Li-ion battery electrodes. We suggest that careful analysis of the thermal decomposition of molecular species may be a way of obtaining hitherto unknown kinetically stabilised polymorphs and amorphous variants of extended solids.