Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (12): 995-1002.DOI: 10.6023/A16080404 Previous Articles     Next Articles

Special Issue: 聚集诱导发光



崔素珍, 杨汉培, 孙慧华, 聂坤, 吴俊明   

  1. 河海大学浅水湖泊综合治理与资源开发教育部重点实验室 河海大学环境学院 南京 210098
  • 投稿日期:2016-08-12 发布日期:2016-11-24
  • 通讯作者: 杨汉培
  • 基金资助:


Doping and Heterojunctional Cooperation of NaNbO3 by Fe and Their Photocatalytic Properties

Cui Suzhen, Yang Hanpei, Sun Huihua, Nie Kun, Wu Junming   

  1. Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098
  • Received:2016-08-12 Published:2016-11-24
  • Supported by:

    Project supported by the Foundation of National Key Scientific Instrument and Equipment Development Project of China (No. 2014YQ060773) and the Priority Academic Program Development of Jiangsu Higher Education Institutions.

The perovskite-type NaNbO3 were prepared through a solvothermal process under a moderate condition followed by calcinations at high temperature.The Fe3+-doping inside the NaNbO3 lattice and the heterojunctions between α-Fe2O3 and NaNbO3 were acquired synchronously in a similar process by treating NaNbO3 with ferric nitrates.The photocatalytic activity of catalysts was evaluated from the photodegradation of Rhodamine B (RhB) in aqueous solution under UV light irradiation and the significant enhancement of degradation rate of aqueous RhB on modified NaNbO3 was observed,with the degradation ratio of RhB reached as high as 95% within 1 h,and the quasi-first-grade rate constant of the RhB degradation reaction over the modified NaNbO3 reached almost 7 times of the pristine one under the experimental conditions.Characterizations by X-ray diffraction (XRD),scanning electron microscopy (SEM),X-ray photoelectron spectroscopy (XPS),UV-vis diffuse reflectance spectrophotometry (DRS),adsorption-desorption of N2 at low temperature (BET calculation),photoluminescence spectroscopy (PL),electron spin resonance spectroscopy (ESR) and photocurrent measurement were performed.The compositions and structures of the as-prepared raw and modified catalysts were carefully identified.It is found that the optimal mass fraction of Fe in modified catalysts is around 2.5%,with about 30% of it exists as Fe3+ inside the lattice of NaNbO3 and the remainder as α-Fe2O3 outside the NaNbO3 lattice.The results of characterizations or measurements suggest that a moderate Nb5+ in NaNbO3 can be substituted by Fe3+ while the perovskite-type structure of NaNbO3 remains unchanging.The moderate Fe-doping into the lattice of NaNbO3 improved the photocatalytic performance of NaNbO3 by the donor level of impurities,charge capturing and adsorption of dissolved oxygen.A fitting amount of α-Fe2O3 cooperates harmoniously with NaNbO3 in degradation of RhB by enhancing the light quantum efficiency through the migration and jumping of electrons or holes between α-Fe2O3 and NaNbO3.It is proposed that the modification (i) promotes the excitation of photocatalysts indicated by an improved light adsorption of modified catalysts on DRS,(ii) suppresses the recombination of photogenerated charge carriers revealed by PL spectra,and (iii) promotes the charge transfer founded by photocurrent measurements.

Key words: NaNbO3, iron modification, photocatalysis, Rhodamine B, promotion mechanism