No abstract

In situ growth of bismuth (Bi) nanoparticles on bulk SrBi 2 Ta 2 O 9 (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.

Morphology-controlled synthesis of tantalates is a major challenge in the field of material science. Herein, an innovative strategy has been developed for controllably synthesizing K1.9Na0.1Ta2O6·2H2O (KNTO) nanocrystals shaped as octahedra and nanosheets without using any capping agents. The obtained nanocrystals show high activity in photocatalytic H2 evolution from CH3OH/H2O solution, and their performance closely depends on the exposed facets, in which the {111}-facet-bounded nanooctahedra exhibit more than 3 times higher activity than the nanosheets dominated with {101} facets. The influence of surface atomic structure and electronic band structure on the photocatalytic properties of the KNTO nanocrystals is systematically studied. This is the first report for the facet controllable synthesis of tantalate materials with highly regular shapes. The present approach is anticipated as a general strategy for controllable synthesis of tantalate materials and also provides feasibility for rational design and activity optimization of shape-controlled photocatalysts for H2 production.