Upconversion Material-Plasmonic Metal-Semiconductor Ternary Heteronanostructures for Wide-Range Solar-to-Chemical...

Harvesting full-spectrum solar energy is a critical issue for developing high-performance photocatalysts. Here, we report a hierarchical heteronanostructure consisting of upconverting, plasmonic, and semiconducting materials as a solar-to-chemical energy conversion platform that can exploit a wide range of sunlight (from ultraviolet (UV) to near-infrared). Lanthanide-doped NaYF₄ nanorod-spherical Au nanocrystals-TiO₂ ternary hybrid nanostructures with a well-controlled configuration and intimate contact between the constituent materials could be synthesized by a wet-chemical method. Notably, the prepared ternary hybrids exhibited high photocatalytic activity for the H₂ evolution reaction under simulated solar and near-infrared light irradiation due to their broadband photoresponsivity and strong optical interaction between the constituents. Through systematic studies on the mechanism of energy transfer during the photocatalysis of the ternary hybrids, we revealed that upconverted photon energy from the upconversion domain transfers to the Au and TiO₂ domains primarily through the Förster resonance energy transfer process, resulting in enhanced photocatalysis.