Issue 7, 2019

Enhanced photocatalysis and bacterial inhibition in Nb2O5via versatile doping with metals (Sr, Y, Zr, and Ag): a critical assessment

Abstract

Unique optical properties render semiconductor Nb2O5 nanoparticles suitable for light harvesting and photocatalytic applications. This study focuses on determining optical properties such as the band gap, conduction band edge, valence band edge and work function of as-prepared solution combustion synthesized Nb2O5 nanoparticles with the help of UV-vis Diffuse Reflectance spectroscopy (DRS) and ultraviolet photoelectron spectroscopy (UPS) techniques. Phase purity and the oxidation states of the elements present in the material were confirmed from X-ray diffraction (XRD) patterns and X-ray photoelectron spectra (XPS), respectively. Doping semiconductors with different metal ions impacts the activity of the material, and therefore efforts were made to understand the effect on the photocatalytic performance of Nb2O5 due to the incorporation of metal dopants viz. Sr, Y, Zr, and Ag. Lattice parameters were obtained from Rietveld refinement of the XRD patterns. Parameters which are closely related to the photoactivity of the catalysts such as the presence of surface defects, oxygen vacancies, surface area, and charge carrier dynamics were determined from photoluminescence (PL) analysis, Brunauer–Emmett–Teller (BET) surface area measurements and time-resolved fluorescence (TRF) analysis respectively. In addition, the dopant concentrations were optimised for enhanced photocatalytic activity. The doped Nb2O5 nanoparticles showed significant activity towards targeted degradation of organic pollutants like 2-chlorophenol (2-CP) and dye contaminants like methylene blue (MB), orange G (OG) and indigo carmine (IC). This strategy yielded a robust response towards inactivation of E. coli and S. aureus as well. Adsorption and photodegradation of MB followed Lagergren's pseudo 1st order reaction model and the Langmuir Hinshelwood model respectively. Bacterial inactivation and OG, IC and 2-CP photodegradation followed 1st order kinetics. The reusability of the catalyst for 5 cycles was demonstrated. Finally, a plausible mechanism is proposed based on radical trapping experiments and combined analysis of the characterization techniques.

Graphical abstract: Enhanced photocatalysis and bacterial inhibition in Nb2O5via versatile doping with metals (Sr, Y, Zr, and Ag): a critical assessment

Supplementary files

Article information

Article type
Paper
Submitted
16 May 2019
Accepted
30 May 2019
First published
30 May 2019
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2019,1, 2748-2760

Enhanced photocatalysis and bacterial inhibition in Nb2O5via versatile doping with metals (Sr, Y, Zr, and Ag): a critical assessment

B. Boruah, R. Gupta, Jayant M. Modak and G. Madras, Nanoscale Adv., 2019, 1, 2748 DOI: 10.1039/C9NA00305C

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