Efficient plasmonic water splitting by heteroepitaxial junction-induced faceting of gold nanoparticles on an anatase titanium( iv ) oxide nanoplate array electrode

Plasmonic photocatalysts represented by gold nanoparticle (NP)-loaded titanium(IV) oxide (Au/TiO₂) can be promising solar-to-fuel converters by virtue of their response to visible-to-near infrared light. Hitherto, Au/rutile (R)-TiO₂ has been recognized as exhibiting photocatalytic activity higher than that of Au/anatase (A)-TiO₂. Herein, we demonstrate that the high potential of A-TiO₂ as the Au NP support can be brought out through atomic level interface control. Faceting of Au NPs is induced by a heteroepitaxial junction on an A-TiO₂(001) nanoplate array (Au/A-TiO₂ NPLA). Photoexcitation towards the Au/A-TiO₂ NPLA electrode generates current for the water oxidation reaction at λ < 900 nm with a maximum efficiency of 0.39% at λ = 600 nm, which is much larger than the values reported so far for the usual electrodes. The striking activity of the Au/A-TiO₂ NPLA electrode was rationalized using a potential-dependent Fowler model. This study presented a novel approach for developing solar-driven electrodes for green and sustainable fuel production.