Constructing NaYF4: Yb, Tm@NH2-MIL-125(Ti) with up-conversion photoluminescence for enhanced full-spectrum photocatalytic performance

Abstract The low utilization of solar energy due to the narrow response spectra limits the performance of current photocatalysts. Utilizing up-conversion photoluminescence is one of the effective methods to enhance photocatalytic ability. A new photocatalyst, NaYF4: Yb, Tm nanoparticles (NYT) embedded in NH2-MIL-125(Ti) (NYT@NH2-MIL-125(Ti)), was constructed aiming to efficiently degrade pollutant under full-spectrum illumination. The characterization certified that NYT had been successfully embedded in NH2-MIL-125(Ti). The photocatalytic activity of NYT@NH2-MIL-125(Ti) was tested by degrading rhodamine B (RhB). The NYT@NH2-MIL-125(Ti) showed significantly enhanced photocatalytic activity compared with NH2-MIL-125(Ti), whose degradation kinetic constant of RhB was 3.73 times that of NH2-MIL-125(Ti). The enhanced photocatalytic performance should be attributed to the expanded response light spectra. Under illumination, NYT absorbs near infrared (NIR) light and emits visible light, which stimulates NH2-MIL-125(Ti) to produce photo-generated electrons-holes. Free radical trapping experiments certified that holes(h+) plays a major role in the photocatalytic process. This work deepens the understanding of construction of high-efficiency photocatalyst with a broad spectrum response, and promotes the application of photocatalysis in water pollution control.