Photo-Assisted Sequential Assembling of Uniform Metal Clusters With Sub-Nanometers on Semiconductor Supports

Dispersing metal subnano-clusters on the oxide supports is attracting close attention in heterogeneous catalysis, but great challenges still lie in controlling the size and dispersion of subnano-clusters due to the inevitable agglomeration. Here, we propose a sequential photochemical deposition strategy named “first store, and then release” to uniformly fabricate the size-controlling noble metal subnano-clusters on semiconductor oxides. Using the typical semiconductor TiO2, the photoexcited electrons can be first stored as reduced species (e.g. Ti3+) under irradiation and the Ti3+ species can optimize both the nucleation and growth processes in dark reaction, resulting in a uniform dispersing of various noble metals (Au, Pt, Ag etc.) with size diameters of ~1 nm. The subnano-clusters catalysts exhibited superior performance in catalytic oxidation of HCHO compared with that of nanoparticles. This work brings a new and useful strategy to construct size-controlling noble metals on the oxide supports for heterogeneous catalysis and the related fields.