A study of size-controlled Au@Cu2O nanocomposite for highly improved methyl orange catalytic performances

Abstract

In this study, we synthesized Au-Cu₂O core–shell nanoparticles (Au@Cu₂O NPs) with epitaxial Cu₂O shell, which have highly improved catalytic performances in methyl orange reduction reaction. We have obtained Au@Cu₂O NPs with different sizes at low temperatures by changing the amount of Cu²⁺ precursor. Both Au and Cu₂O are catalytic materials, especially Cu₂O, as a p-type semiconductor, whose catalytic ability depends on the crystalline facets. Catalytic reduction of methyl orange (MO) was used as a model system to explore the catalytic properties of Au@Cu₂O nanocomposite. In comparison to pure Au and Cu₂O NPs, the catalytic performance of Au@Cu₂O has a noticeable improvement. The best catalytic rate was ~ 22 times faster than that of AuNRs and ~ 4 times than that of Cu₂O NPs. By studying the catalytic mechanism, it is supposed that the Schottky barrier at the Au-Cu₂O interfaces leads to the charge separation, which is beneficial to catalysis. Therefore, the Au@Cu₂O NPs we designed with controllable shell thickness is an ideal composite material in the catalyst domain.