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Enhanced photocatalysis and bacterial inhibition in Nb2O5: Via versatile doping with metals (Sr, Y, Zr, and Ag): A critical assessment

Boruah, B and Gupta, R and Modak, JM and Madras, G (2019) Enhanced photocatalysis and bacterial inhibition in Nb2O5: Via versatile doping with metals (Sr, Y, Zr, and Ag): A critical assessment. In: Nanoscale Advances, 1 (7). pp. 2748-2760.

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Official URL: https://doi.org/10.1039/c9na00305c


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.

Item Type: Journal Article
Publication: Nanoscale Advances
Publisher: Royal Society of Chemistry
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Aromatic compounds; Catalysts; Complexation; Dyes; Energy gap; Escherichia coli; Integrated circuits; Metal analysis; Metal ions; Metals; Nanoparticles; Niobium oxide; Optical properties; Organic pollutants; Photoelectron spectroscopy; Photoelectrons; Photons; Reusability; Rietveld refinement; Semiconductor doping; Surface defects; Synthesis (chemical); Ultraviolet photoelectron spectroscopy; X ray diffraction, Brunauer-emmett-teller surface areas; Characterization techniques; Langmuir-Hinshelwood models; Photocatalytic application; Photocatalytic performance; Time-resolved fluorescence; UV-Vis diffuse reflectance spectroscopy; X ray photoelectron spectra, Photocatalytic activity
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Date Deposited: 27 Oct 2022 05:41
Last Modified: 27 Oct 2022 05:41
URI: https://eprints.iisc.ac.in/id/eprint/77586

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