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Nb-doped TiO2 cathode catalysts for oxygen reduction reaction of polymer electrolyte fuel cells

Paper ID Volume ID Publish Year Pages File Format Full-Text
54328 47005 2014 6 PDF Available
Title
Nb-doped TiO2 cathode catalysts for oxygen reduction reaction of polymer electrolyte fuel cells
Abstract

•Nb:TiO2 catalysts were examined for oxygen reduction reaction.•Nb:TiO2 was synthesized from Nb-doped TiN nanoparticles.•Nb:TiO2 catalysts showed remarkable activity after H2 treatment.•The function of carbon residues was considerable.

Nb-doped TiO2 particles were studied as electrocatalysts for the oxygen reduction reaction (ORR) under acidic conditions. The Nb-doped TiN nanoparticles were first synthesized by meso-porous C3N4 and then fully oxidized to Nb-doped TiO2 by immersing in 0.1 M H2SO4 at 353 K for 24 h. Although the ORR activity of the as-obtained sample was low, a H2 treatment at relatively high temperature (1173 K) dramatically improved the ORR performance. An onset potential as high as 0.82 VRHE was measured. No degradation of the catalysts was observed during the oxidation–reduction cycles under the ORR condition for over 127 h. H2 treatment at temperatures above 1173 K caused the formation of a Ti4O7 phase, resulting in a decrease in ORR current. Elemental analysis indicated that the Nb-doped TiO2 contained 25 wt% residual carbon. Calcination in air at 673 or 973 K eliminated the residual carbon in the catalyst, which was accompanied by a dramatic decrease in ORR activity. This post-calcination process may reduce the conductivity of the sample by filling the oxygen vacancies, and the carbon residue in the particle aggregates may enhance the electrocatalytic activity for ORR. The feasibility of using conductive oxide materials as electrocatalysts is discussed.

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Keywords
Cathode catalyst; Polymer electrolyte fuel cells; Non-Pt catalysts; Oxygen reduction reaction; Conductive oxides
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Nb-doped TiO2 cathode catalysts for oxygen reduction reaction of polymer electrolyte fuel cells
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 233, 15 September 2014, Pages 181–186
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