Facile one-step synthesis and enhanced photocatalytic activity of a WC/ferroelectric nanocomposite

Abstract

The development of noble-metal-free co-catalysts is seen as a viable strategy for improving the performance of semiconductor photocatalysts. Although the photocatalytic efficiency of ferroelectrics is typically low, it can be enhanced through the incorporation of a co-catalyst into nanocomposites. Here, we demonstrate the influence of ferroelectricity on the decolorization of rhodamine B under simulated solar light using RbBi₂Ti₂NbO₁₀ and compared the performance with that of non-ferroelectric RbBi₂Nb₅O₁₆. The decolorization rate for RbBi₂Ti₂NbO₁₀ was 5 times greater than that of RbBi₂Nb₅O₁₆. This behaviour can be explained in terms of ferroelectric polarization, which drives the separation of charge carriers. The photocatalytic activity of RbBi₂Ti₂NbO₁₀ was further enhanced to over 30 times upon preparing a nanocomposite with tungsten carbide (WC) through high energy ball milling. This enhancement was attributed not only to the increased specific surface area, but also to the incorporated WC co-catalyst, which also serves as a source of plasmonic hot electrons and extends the photocatalytic activity into the visible light range. The WC/RbBi₂Ti₂NbO₁₀ nanocomposite shows interesting water oxidation properties and evolves O₂ with a rate of 68.5 μmol h⁻¹ g⁻¹ and a quantum yield of 3% at 420 nm. This work demonstrates a simple route for preparing WC containing nano-ferroelectric composites for solar energy conversion applications.