Visible light photoelectrochemical response of copper deposited titanium dioxide nanotubes

This paper presents a novel preparation of copper (Cu) deposited titanium dioxide (TiO2) nanotubes in photoelectrochemical systems. The main target was improving TiO2 applications in the areas of energy conversion under visible light. Herein, we investigated different amount of Cu deposited TiO2 nanotubes using thermal evaporation technique. Based on the results, small amount of Cu (1.09 wt.%) showed the improvement in photoelectrochemical (PEC) response under visible light. Optimum amount of Cu deposited on TiO2 nanotubes will inhibit recombination rate of photogenerated charge carriers and improve the charge separation and transfer under visible light illumination. However, the excess amount of Cu deposited on TiO2 nanotubes will impede the photocurrent to flow and resulted in lower photoconversion efficiency. The reason may be attributed to the formation of composite structure on TiO2 nanotubes that serve as defects in the Cu/TiO2 interface by the lattice mismatch that will serve as recombination site for the charge carriers.