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Title: Organic pollutant photodecomposition by Ag/KNbO3 nanocomposites: A combined experimental and theoretical study

In this study, Ag nanoparticles supported on well-defined perovskite orthorhombic KNbO3 nanowires are synthesized via facile photoreduction and systematically characterized by XRD, Raman, DRUV–vis, XPS, PL, TEM, HRTEM, and HAADF-STEM. The photoreactivity of Ag/KNbO3 nanocomposites as a function of Ag contents (0.4–2.8 wt %) is assessed toward aqueous rhodamine B degradation under UV- and visible-light, respectively. It is found that the UV-induced photoreactivity initially increases and then decreases with increasing Ag contents. At an optimal Ag content (ca. 1.7 wt %), the greatest photoreactivity is achieved under UV light, with the photocatalytic reaction rate of 1.7 wt % Ag/KNbO3 exceeding that of pristine KNbO3 by a factor of ca. 13. In contrast, visible light-induced photoreactivity monotonically increases with increasing Ag contents in the range of 0.4–2.8 wt %. On the basis of the detected active species and intermediate products in the photocatalytic processes, conjugated structure cleavage and N-deethylation are revealed to be the respective predominant pathway under UV and visible-light illumination. To gain an insight into the observed photoreactivity, the electronic properties of Ag/KNbO3 have been investigated using spin-polarized DFT calculations. Herein, Ag extended adlayers (1–4 ML) on the slab models of KNbO3 (101) are employed to mimic large supportedmore » Ag nanoparticles. A Bader analysis of the electron density shows a small net charge transfer (ca. 0.1 e) from KNbO3 to Ag. The electron localization function of Ag/KNbO3 (101) illustrates that Ag adlayers with thickness larger than 2 ML are essentially metallic, and weak polarization occurs at the interface. In addition, the metallic Ag adlayers generate a continuum of Ag bandgap states, which play a key role in determining different Ag content-dependent behavior between UV and visible-light illumination.« less
 [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [5] ;  [3] ;  [3]
  1. Northeastern Univ., Shenyang (China); National Center for Nanoscience and Technology, Beijing (China)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. National Center for Nanoscience and Technology, Beijing (China)
  4. Wuhan Univ. of Technology, Wuhan (China)
  5. Northeastern Univ., Shenyang (China)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1932-7447; R&D Project: CO009; KC0302010
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 120; Journal Issue: 5; Journal ID: ISSN 1932-7447
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY nanocomposites; localized surface plasmon resonance; photocatalysis; potassium niobate; silver