Optimized FTO seeding enables the growth of highlyefficient Ta-doped TiO 2 nanorod photoanodes.

Tantalum doped rutile nanorods were hydrothermally grown on FTO substrates using a new seeding approach. This approach allows the incorporation of high concentrations of up to 4.8 at% tantalum as active doping and results in a significant enhancement of the photoelectrochemical water splitting rate (1.8 mA cm-2 at a potential of +1.5 V vs. RHE) which corresponds to ∼1% photocurrent conversion efficiency under AM 1.5, 100 mW cm-2 simulated sunlight irradiation.