Photocatalytic activity of Cu2O nanoparticles prepared through novel synthesis method of precursor reduction in the presence of thiosulfate

A novel fabrication of Cu2O nanoparticles was successfully achieved through the reduction of Cu2+ in the interlayer of montmorillonite (denoted as MT). The Cu2O nanoparticles formed in the clay interlayer (denoted as Cu2O/MT) had a lamellate shape of 20–100 nm in width and ca. 0.39 nm in thickness, and thus, the Cu2O/MT exhibited a higher specific surface area than neat Cu2O. The Cu2O/MT was applied to a photocatalyst, and its photocatalytic activity was examined in terms of water reduction (i.e., H2 evolution) in the presence of methanol (electron donor). The Cu2O/MT showed a high photocatalytic activity in comparison with neat Cu2O; moreover, the photocatalytic activity was improved by loading a Pt catalyst onto the surface of Cu2O. Based on the dependencies of photocatalytic activity on light intensity as well as methanol concentration, it was revealed that the H2 evolution from water on Cu2O/MT is the rate-determining step. Thus, the active and efficient photocatalysis of Cu2O/MT was associated with an increase in specific surface area corresponding to the number of active sites.

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