A new silver metaniobate semiconductor of Ag0.5La0.5Nb2O6 with defect-perovskite structure

作者：Mi, Longqing; Feng, Yongyi; Cao, Lei; Xue, Mingqiang; Huang, Yanlin^*; Qin, Lin; Seo, Hyo Jin^*

来源：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 2018, 192: 59-66.

DOI：10.1016/j.saa.2017.11.006

• Semiconductor
• Photocatalysis
• Niobate
• Perovskite-type structure
• Optical materials and properties
• Luminescence

Silver-containing lanthanum metaniobate Ag0.5La0.5Nb2O6 nanoparticles were synthesized by sol-gel polymerized complex method. A typical defect-perovskite structure was confirmed by XRD Rietveld refinements. The surface characteristics of the sample were tested by SEM, TEM and EDS measurements. SEM and TEM show that the sample presents ball-like particles with the diameters of 100 nm to 400 nm. The sample shows both self-activated luminescence and photocatalytic activities. Ag0.5La0.5Nb2O6 has a direct transition with band energy of 2.85 eV. The Ag4d-O2p hybridization in the valence band contributes to the narrowed band gap. The luminescence properties of Ag0.5La0.5Nb2O6 have been investigated for the first time. The luminescence is characterized by two emission centers with maximum wavelength near 460 and 530 nm. The emission and excitation spectra, decay curves and the thermal quenching mechanism were discussed. Ag0.5La0.5Nb2O6 shows the efficient photocatalytic activities and the photodegradation rate for methylene blue dye (MB) can reach about 95% under visible light (>420 nm) irradiation in 5 h. The trapped experiments for the active species were tested and discussed, which verified that center dot OH radicals could be the major active species in photocatalysis.

• 出版日期2018-3-5
• 单位苏州大学