Enhanced photocatalytic water splitting of TiO₂ by decorating with facet-controlled Au nanocrystals

Localized surface plasmon resonance (LSPR) has drawn much interest in photocatalysis due to the advantages in extending light-absorption and improving charge-separation efficiency. In this work, Au nanocubes with exposed {100} facets and Au nanotrioctahedrons with exposed {221} facets are synthesized via the seed-growth method with the aim of demonstrating the photocatalytic performance under the LSPR effect using a typical TiO₂ photocatalyst. The modification of Au nanocrystals results in accelerated charge separation in the TiO₂ photocatalyst, which is attributed to the synergetic effect of local electromagnetic field enhancement from the LSPR effect and the Schottky junction established in Au and TiO₂. Consequently, the photocatalytic hydrogen-production from the TiO₂ photocatalyst is greatly improved. Moreover, Au nanotrioctahedrons modified TiO₂ exhibits superior photocatalytic performance due to the stronger local electromagnetic field of the LSPR and the more efficient electron trapping originated from the unique morphology with exposed {221} facets.