Water splitting using a three-dimensional plasmonic photoanode with titanium dioxide nano-tunnelsElectronic supplementary information (ESI) available. See DOI: 10.1039/c6gc03217f

• Main Authors: Takakura, Ryohei, Oshikiri, Tomoya, Ueno, Kosei, Shi, Xu, Kondo, Toshiaki, Masuda, Hideki, Misawa, Hiroaki
• Format: Article
• Language: English
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/c6gc03217f

In this study, we developed a three-dimensional plasmonic photoanode using titanium dioxide nano-tunnels (TNTs) loaded with gold nanoparticles (Au-NPs) for water splitting, to enhance the reaction efficiency. We also optimized the procedure of loading Au-NPs on complex three-dimensional structures. We discuss the correlation between the plasmon-induced charge separation obtained from photoelectrochemical measurement and the morphology of Au-NPs observed by transmission electron microscopy. We have successfully deposited well-dispersed Au-NPs on the walls of TNTs using HAu(OH) 4 as a precursor. The amount of Au-NPs on the TNTs was estimated to be approximately 15-fold larger than that on the thin film titanium dioxide substrate, and the particle size remained small. Photoelectrochemical water splitting was achieved by using a two-electrode system rather than a three-electrode system. Furthermore, stoichiometric water splitting was confirmed by estimating the amounts of the evolved H 2 and O 2 gases under visible light irradiation. A three-dimensional plasmonic photoanode using titanium dioxide nano-tunnels loaded with gold nanoparticles for water splitting was developed.