A novel method for preparing BiOI nanoplates and their use as precursors to synthesize porous BiVO4 water oxidation photocatalysts

Abstract

In this work, we report an innovative method for synthesizing BiOI nanoplate powder by a slow basification of an aqueous solution constituted of Bi(NO₃)₃ and KI. The basification was done with NH₃ vapor which was naturally generated on top of an NH₄OH solution kept in a closed space. The impact of the basification rate on the morphology and crystallinity of the BiOI product was investigated. Herein, we also report on the use of newly produced BiOI nanoplate powder together with the VO(acac)₂ precursor for fabricating BiVO₄ photoanodes for solar driven water splitting applications. We also discuss how the morphology of BiOI nanoplates and their orientation on a fluorine doped tin oxide substrate will affect the morphology, topology and photocatalytic performance of the electrode. The BiVO₄ photoanode showed a photocatalytic current density of 0.55 mA cm⁻² at 1.23 V vs. the Reversible Hydrogen Electrode (RHE) when assayed in a pH 7 phosphate buffer electrolyte and under 1 sun illumination.