A facile and green approach to synthesize Pt@CeO2 nanocomposite with tunable core-shell and yolk-shell structure and its application as a visible light photocatalyst

Abstract

We report a very facile and green template-free hydrothermal approach to synthesize Pt@CeO₂ nanocomposite in an aqueous phase with tunable core-shell and yolk-shell structure. The formation of such core-shell and yolk-shell Pt@CeO₂ nanocomposites can be reasonably explained by a novel mechanism of combined synergy interaction of heterogeneous seeded growth process and Ostwald ripening process, which is distinctly different from the well-known physical phenomena, such as nanoscale Kirkendall effect, Ostwald ripening and oriented attachment, employed in wet-chemistry fabrications of core/yolk-shell inorganic nanostructures. Interestingly, we show that, using selective oxidation of benzyl alcohol as a probe reaction at room temperature and ambient pressure, the incorporation of Pt into the shell of semiconductor CeO₂ can remarkably enhance the photocatalytic performance of CeO₂ for selective oxidation of alcohol. This represents a first example on the application of metal core@semiconductor-oxide shell nanostructured composite materials as visible-light-driven photocatalyst to selective oxidation reactions. Therefore, our findings could not only offer a useful direction on scale-up fabrication of other metal-oxide-coated noble metal nanocomposites with tunable core/yolk-shell structure, but also point to promising vistas of such metal core@oxide shell semiconductor nanocomposites as a novel class of materials platform as visible-light-driven photocatalyst in selective organic transformations.