Photocatalytic activity of Cu 2O nanoparticles prepared through novel synthesis method of precursor reduction in the presence of thiosulfate

Abstract

A novel fabrication of Cu 2O nanoparticles was successfully achieved through the reduction of Cu 2+ in the interlayer of montmorillonite (denoted as MT). The Cu 2O nanoparticles formed in the clay interlayer (denoted as Cu 2O/MT) had a lamellate shape of 20–100 nm in width and ca. 0.39 nm in thickness, and thus, the Cu 2O/MT exhibited a higher specific surface area than neat Cu 2O. The Cu 2O/MT was applied to a photocatalyst, and its photocatalytic activity was examined in terms of water reduction (i.e., H 2 evolution) in the presence of methanol (electron donor). The Cu 2O/MT showed a high photocatalytic activity in comparison with neat Cu 2O; moreover, the photocatalytic activity was improved by loading a Pt catalyst onto the surface of Cu 2O. Based on the dependencies of photocatalytic activity on light intensity as well as methanol concentration, it was revealed that the H 2 evolution from water on Cu 2O/MT is the rate-determining step. Thus, the active and efficient photocatalysis of Cu 2O/MT was associated with an increase in specific surface area corresponding to the number of active sites.