Nano-Structuration of WO 3 Nanoleaves by Localized Hydrolysis of an Organometallic Zn Precursor: Application to Photocatalytic NO 2 Abatement.

WO is a known photocatalytic metal oxide frequently studied for its depollution properties. However, it suffers from a high recombination rate of the photogenerated electron/holes pair that is detrimental to its performance. In this paper, we present a new chemical method to decorate WO nanoleaves (NLs) with a complementary metal oxide (ZnWO) in order to improve the photocatalytic performance of the composite material for the abatement of 400 ppb NO under mild UV exposure. Our strategy was to synthesize WO·2HO nanoleaves, then, to expose them, in water-free organic solution, to an organometallic precursor of Zn(Cy). A structural water molecule from WO·2HO spontaneously decomposes Zn(Cy) and induces the formation of the ZnO@WO·HO nanocomposite. The material was characterized by electronic microscopy (SEM, TEM), TGA, XRD, Raman and solid NMR spectroscopies. A simple thermal treatment under air at 500 °C affords the ZnWO@WO nanocomposite. The resulting material, additionally decorated with 1% wt. Au, presents a remarkable increase (+166%) in the photocatalytic abatement of NO under UV compared to the pristine WO NLs. This synthesis method paves the way to the versatile preparation of a wide range of MOx@WO nanocomposites (MOx = metal oxide).