High-yield synthesis and hybridizations of Cu microplates for catalytic applications

Abstract

Because of their special geometrical features, which include a high specific surface area and high proportion of exposed surface atoms, two-dimensional (2D) metal nanostructures based on Au and Ag have been actively used as high-performance catalysts. However, 2D Cu nanostructures have not been intensively used because of their difficult synthesis and poor oxidation resistance. In this study, aqueous-solution-based hybridization approaches based on the chemical conversion of the surface of 2D Cu nanostructures are used to prepare high-performance catalysts. First, the coordination-based synthesis strategy is successfully used to produce Cu microplates with large lateral dimensions and thin thickness in high yield. And then, Cu@Cu₂S metal–semiconductor hybrid microplates were successfully synthesized within 10 minutes from Cu microplates via a sulfidation reaction using aqueous sodium sulfide under ambient conditions. The as-prepared Cu@Cu₂S microplates were used as photocatalysts for the decomposition of methylene blue (MB) under solar irradiation and their photocatalytic activity and stability were investigated. Finally, Cu–Au bimetallic hybrid microplates with nanocavities and a rough surface were prepared using the Cu microplates as templates for a galvanic replacement reaction with gold(III) chloride hydrate. The Cu–Au hybrid microplates were used to as heterogeneous catalysts for the hydrogenation of 4-nitrophenol by sodium borohybride, and the catalytic activity and stability of the hybrid microplates were evaluated.