A NIR-driven photocatalyst based on α-NaYF4:Yb,Tm@TiO2 core–shell structure supported on reduced graphene oxide

The development of near-infrared (NIR) light-driven photocatalysts is needed to utilize the large portion of NIR energy in sunlight. In this work, a new strategy to fabricate advanced upconversion-based NIR-driven photocatalysts was developed by integrating core–shell nanostructure of α-NaYF4:Yb,[email protected]2 with reduced graphene oxide (RGO) nanosheets. This new α-NaYF4:Yb,[email protected]2/RGO composite was synthesized by a facile wet chemical method. The product exhibited significantly enhanced photocatalytic activity than bare α-NaYF4:Yb,[email protected]2 and α-NaYF4:Yb,Tm/TiO2/RGO physical mixture for the degradation of various organic pollutants, including methylene blue (MB), methyl orange (MO) and phenol, under NIR (980 nm laser) irradiation. Highly reactive hydroxyl radicals (OH) were found to be the major reactive species. It was revealed that the core–shell structure of α-NaYF4:Yb,[email protected]2 improved the upconverison UV energy transfer, while the incorporation of RGO facilitated the photo-generated e−–h+ separation after excited by the upconversion energy. Our discovery highlights the potential of developing NIR-driven photocatalysts by taking advantage of the synergic effects of core–shell upconversion materials combined with graphene for environmental and energy-related applications.