A Facile One Pot Synthesis of Cu2O@TiO2: A Nanocomposite Catalyst for Enhanced Visible Light Driven Photocatalysis#`

摘要

The highlight of this study is a successful attempt to obtain a visible light active photo catalyst by a single step synthesis procedure.The photocatalytic performance of Cu2O,a p-type semiconducting oxide with a band gap in the visible region of the solar spectrum is improved by the presence of TiO2 on its surface.Nanocomposites of Cu2O@TiO2 were synthesized by a facile one pot synthesis route.X-ray diffraction(XRD)studies confirmed the face centred cubic structure of Cu2O but was inconclusive about the TiO2 presence.Field Emission Scanning Electron Microscopy(FE-SEM)images confirmed the octahedral morphology of the Cu2O particles and the presence of Ti and O on the surface.High Resolution Transmission Electron Microscopy(HR-TEM)and Selected Area Electron Diffraction(SAED)studies established the presence of nanocrystalline anatase TiO2 on the Cu2O interfaces.The specific role of the nanoparticles of n-type TiO2 positioned on the p-type Cu2O in improving photo-activity and making it visible light active was demonstrated.The photocatalytic activity of the composite was demonstrated by the degradation of a model dye Rhodamine B using visible light.It is observed that the photocatalytic activity is dependent on density of heterojunctions formed in the photo-system which the nano-crystalline TiO2,has very effectively created on the Cu2O surface,which are responsible for the improved photocatalytic response.This work establishes that the in-situ creation of Cu2O@TiO2 is effective in creating pn heterojunctions at the Cu2O@TiO2 interface,which result in arresting the recombination processes,leading to improved photocatalytic performance.