Boosting NIR-driven photocatalytic water splitting by constructing 2D/3D epitaxial heterostructures

Heterostructures, which can possess advantages of materials with different properties, have attracted enormous attention in various research fields including solar cells, photocatalysts, and optical electronic devices. In this work, a 2D/3D atomic epitaxial heterostructure with ultrathin BiOCl nanosheets and YF₃:Yb, Tm octahedral crystals was fabricated via the halogen atom exchange method in the solution phase. The epitaxial heterointerface can facilitate energy transfer between BiOCl and YF₃:Yb, Tm and suppress the energy quenching induced by grain boundaries. By carrying out single-particle confocal characterization, the energy upconverted by YF₃:Yb, Tm is quantitatively confirmed to be transferred to ultrathin BiOCl nanosheets. As a result, YF₃:Yb, Tm@BiOCl displays outstanding NIR-driven water splitting and waste-water cleaning properties. This study paves the way to fabricate 2D/3D epitaxial heterostructures, which helps to broaden the application of typical 2D materials.