Photoinduced Topotactic Growth of Bismuth Nanoparticles from Bulk SrBi2Ta2O9

In situ growth of bismuth (Bi) nanoparticles on bulk SrBi2Ta2O9 (SBT) platelet is achieved by UV light illumination of SBT in aqueous glucose solutions. Interestingly, the as-produced Bi nanoparticles (NPs) are uniformly oriented with the epitaxial relationship of [001]Bi//[110]SBT, appearing as meso-single-crystal phase despite spatial separation between the NPs. Systematic investigations indicate that Bi(III) at the (110)SBT plane is topotactically reduced by photogenerated electrons, producing Bi atoms serving as nucleation seeds oriented from the (003) plane. Further growth of these oriented nuclei leads to formation of Bi NPs arranged laterally in mesocrystalline superstructure. The reported finding presents a simple, environmentally friendly approach toward preparation of highly organized, surface supported metal NPs through direct photoreduction of bulk metal oxides.