A Facile One Pot Synthesis of Cu 2 O@TiO 2 : A Nanocomposite Catalyst for Enhanced Visible Light Driven Photocatalysis #

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 Cu 2 O, a p‐type semiconducting oxide with a band gap in the visible region of the solar spectrum is improved by the presence of TiO 2 on its surface. Nanocomposites of Cu 2 O@TiO 2 were synthesized by a facile one pot synthesis route. X‐ray diffraction (XRD) studies confirmed the face centred cubic structure of Cu 2 O but was inconclusive about the TiO 2 presence. Field Emission Scanning Electron Microscopy (FE‐SEM) images confirmed the octahedral morphology of the Cu 2 O 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 TiO 2 on the Cu 2 O interfaces. The specific role of the nanoparticles of n‐type TiO 2 positioned on the p‐type Cu 2 O 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 TiO 2 , has very effectively created on the Cu 2 O surface, which are responsible for the improved photocatalytic response. This work establishes that the in‐situ creation of Cu 2 O@TiO 2 is effective in creating p‐n heterojunctions at the Cu 2 O@TiO 2 interface, which result in arresting the recombination processes, leading to improved photocatalytic performance.