Constructing two-dimensional CuFeSe₂@Au heterostructured nanosheets with an amorphous core and a crystalline shell...

Although substantial efforts have been made toward the synthesis of noble metal-semiconductor heteronanostructures, direct in situ synthesis of two-dimensional (2D) core-shell semiconductor@noble metal heterostructured nanosheets remains largely unexplored. Herein, we report the synthesis of a novel 2D core-shell CuFeSe₂@Au heterostructured nanosheet with an amorphous core and a crystalline shell based on the reversed growth of Au nanosheets on the CuFeSe₂ frameworks under near-infrared (NIR) illumination. The nanosheet exhibits strong absorbance in the NIR region, and the valence band top of CuFeSe₂@Au nanosheets is higher than the oxidation potential of O₂/H₂O. Owing to the unique structural features, the resulting nanosheets show excellent photocatalytic activity and high stability toward water oxidation with an O₂ generation rate up to 3.48 mmol h^-1 g^-1 compared to those of the constituent materials under NIR light irradiation (λ > 850 nm). This work brings new opportunities to prepare 2D core-shell semiconductor@noble metal heterostructured nanosheets, which can be applied as photocatalysts toward water splitting and solar energy conversion at long wavelengths.