Highly controlled coating of biomimetic polydopamine in TiO2 nanotubes

• Highly-controlled polydopamine coating can be easily performed in TiO2 nanotubes.
• Polydopamine acts as a photonic sensitizer.
• The polydopamine thin films can be used to decorate TiO2 nanotubes with metal nanoparticles and co-catalysts.
• Coated and decorated TiO2 nanotube photoanodes produce higher photocurrents under the visible solar spectrum.

Highly controlled coating of biomimetic polydopamine (PDA) was achieved on titanium dioxide nanotubes (TiO2 NTs) by exposing TiO2 NT arrays to a slightly alkaline dopamine solution. The thin films act as photonic sensitizers (enhancing photocurrents and photodegradation) in the visible light range. The PDA coatings can furthermore be used as a platform for decorating the TiO2 NTs with different co-catalysts and metal nanoparticles (NPs).