Titanium Oxide Nanotubes Doped for Use in a Visible-Light Biophotofuel Cell

Multiple metal and non-metal dopants were added to titanium oxide nanotubes to enhance the photosensitive behavior. Six elements including nitrogen, sulfur, zinc, copper, cobalt, and nickel were incorporated into titanium oxide as the dopants. The doped titanium oxide nanotubes were made into photosensitive anodes and placed in ethanol to form fuel cells. The open circuit voltage measurement results showed that after doping, all the specimens tested were allowed the absorption of visible light. However, the resulted in voltages were slightly less than of those obtained through ultraviolet light absorption tests. Among the transition metal doping elements and the non-metal elements, cobalt, nickel and zinc showed the most promise in improving the visible light absorption.