Fluorescence resonance energy transfer induced broadband photoresponse for highly efficient solar-driven photocatalysis

Developing efficient photocatalysts with near-infrared (NIR) light responsiveness to enhance solar energy utilization efficiency holds significant scientific importance. In this work, β-NaLuF₄: Yb³⁺/Tm³⁺ upconversion nanoparticles are selected as the NIR light converter and integrated with the non-metallic semiconductor graphitic carbon nitride (g-C₃N₄) to fabricate a photocatalytic material β-NaLuF₄: Yb³⁺/Tm³⁺@SiO₂@g-C₃N₄ (LTSC), which can simultaneously respond to ultraviolet, visible and NIR light. Spectroscopic analysis, including photoluminescence spectra and lifetime decay curves of the samples, reveals a highly efficient fluorescence resonance energy transfer (FRET) mechanism between Tm³⁺: ¹I₆ and ¹D₂ state and g-C₃N₄, which allows g-C₃N₄ to generate photoinduced carriers under NIR light irradiation for photocatalytic reactions. Quantitative evaluation using Rhodamine B as a model pollutant demonstrates that LTSC exhibits exceptional photodegradation efficiency and rate under the solar illumination, outperforming conventional photocatalysts in the corresponding class. Additionally, the photocatalytic mechanism is systematically elucidated through comprehensive photoelectrochemical characterizations. This work not only provides a highly efficient broadband responsive photocatalyst LTSC, but also establishes a rational design strategy for developing such materials.