Hydrogen evolution from solar water splitting on nanostructured copper oxide photocathodes

Copper oxide has received much attention as a photocatalyst for solar water splitting, since it has a band gap of ∼2.0 eV with favourable energy band positions for water cleavage; it is abundant and environmentally friendly. In this paper, we report the preparation of copper oxide thin films on copper substrate with different morphology by a solution route in large scales. The method was simple, low cost, and can be completed in the absence of any surfactant. Copper oxide films were characterised by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Fourier transform-infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The XRD analysis and FT-IR analysis confirm the formation of copper oxide films. SEM images show gradual development of hierarchical structures of copper oxide with different morphology. The films were successfully tested as photocathodes in a photoelectrochemical cell, and their photocatalytic activity was evaluated by testing the solar water splitting. The photocatalytic activity of these films was found to be size-dependent and films with smaller dimensions demonstrated a significant increase in photocatalytic activities during solar water splitting process. Based on the above discussion, we believe that these samples are attractive candidates as a visible-light-driven photocatalyst. © 2016 Informa UK Limited, trading as Taylor & Francis Group.