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Photocatalytic activity of Fe-modified bismuth titanate pyrochlores: Insights into its stability, photoelectrochemical, and optical responses

Paper ID Volume ID Publish Year Pages File Format Full-Text
45262 46407 2016 9 PDF Available
Title
Photocatalytic activity of Fe-modified bismuth titanate pyrochlores: Insights into its stability, photoelectrochemical, and optical responses
Abstract

•Bi2Ti2O7 with Fe & Pt is tested as photocatalyst for methyl orange phytoremediation.•The effects of catalyst loading, dye concentration, & kinetic parameters reported.•Pt enhances UV–vis & visible light activity of Fe-BTO by 36% & 40%, respectively.•Photoelectrochemical (EIS,V/t) offer insights on Fe-BTO photoactivity.•Stability tests show >80% recovery of the photoactivity after 3 successive 2 h runs.

This work examines the catalytic activity of a pyrochlore phase bismuth titanate (Bi2Ti2O7–BTO) in driving the photo-assisted decomposition of a model pollutant, methyl orange (MO). The photoactivity of the BTO has been probed with the inclusion of Fe with BTO and with the addition of a co-catalyst- Pt external to the Fe-BTO. The addition of Fe enhances BTO photoactivity by ∼38%, while the presences of Pt along with Fe demonstrate the most favorable increase at 88% compared to the plain BTO. The MO degradation follows a pseudo first order kinetics. Under 100% visible light illumination, all catalysts demonstrate photoactivity. Specifically, a 10%, 15%, and 21% degradation of MO with BTO, Fe-BTO, and Pt/Fe-BTO, respectively, is noted. Stability analysis indicates that a mild oxidative treatment at 350 °C is sufficient to recover ∼86% of the photoactivity lost over 6 h of exposure to photoillumination in 2 h increments. Further, for the first time, complementary photoelectrochemical and optical measurement tools have been used to systematically probe the functioning of BTO in the presence of Fe and Pt. Electrochemical impedance, chronopotentiometry (intermittent illumination studies), and fluorescence measurements reveals (i) Fe aids in visible light assisted charge separation, (ii) Pt is not as effective with visible light as it is with UV, and (iii) a high concentration of hydroxyl radical in the Pt/Fe-BTO is the basis for improved photoactivity of the catalysts. Using bismuth titanate pyrochlore as a case study, this work demonstrates the approach to leverage optical and photoelectrochemical tools for systematic analysis of other multi-metal oxides that belong to the sillenite, delafossites, pyrochlores, and scheelites.

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Keywords
Bismuth titanate; Methyl orange; Photodegradation; Reusability; Photoelectrochemistry
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Photocatalytic activity of Fe-modified bismuth titanate pyrochlores: Insights into its stability, photoelectrochemical, and optical responses
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 180, January 2016, Pages 442–450
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us