Visible light-induced water splitting in an aqueous suspension of a plasmonic Au/TiO(2) photocatalyst with metal co-catalysts

We found that plasmonic Au particles on titanium(iv) oxide (TiO(2)) act as a visible-light-driven photocatalyst for overall water splitting free from any additives. This is the first report showing that surface plasmon resonance (SPR) in a suspension system effectively induces overall water splitting. Modification with various types of metal nanoparticles as co-catalysts enhanced the evolution of H(2) and O(2). Among these, Ni-modified Au/TiO(2) exhibited 5-times higher rates of H(2) and O(2) evolution than those of Ni-free Au/TiO(2). We succeeded in designing a novel solar energy conversion system including three elemental technologies, charge separation with light harvest and an active site for O(2) evolution (plasmonic Au particles), charge transfer from Au to the active site for H(2) production (TiO(2)), and an active site for H(2) production (Ni cocatalyst), by taking advantage of a technique for fabricating size-controlled Au and Ni nanoparticles. Water splitting occurred in aqueous suspensions of Ni-modified Au/TiO(2) even under irradiation of light through an R-62 filter.