کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
220682 463346 2007 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Preparation and characterization of Nb-doped TiO2 nanoparticles used as a conductive support for bifunctional CuCo2O4 electrocatalyst
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Preparation and characterization of Nb-doped TiO2 nanoparticles used as a conductive support for bifunctional CuCo2O4 electrocatalyst
چکیده انگلیسی

Nb-doped TiO2 powders with various Nb contents (0%, 5% and 10%) were prepared using a sol–gel process and annealed at 450, 650 and 1050 °C with the aim to be used as a conductive support for bifunctional electrocatalysts in rechargeable metal-air batteries, substituting the more conventional carbon particles which slowly corrode at high potentials during cell recharge. X-ray diffraction analyses revealed that niobium hinders the anatase–rutile transformation and prevents the grain growth, which is important to achieve a conductive support with high specific surface area. X-ray photoelectron spectroscopy measurements have shown that the powders possess surface Ti4+and Nb4+species, and that the Nb0.05Ti0.95O2 (1050 °C) sample also contains Ti3+and Nb5+ ions. Composite film electrodes containing CuCo2O4 particles (60 w/w%), Nb0.05Ti0.95O2 or Vulcan XC72R or Ebonex powder (25%), and poly(vinylidene fluoride-co-hexafluoropropylene) (15%) were formed on the glassy carbon disk surface of a rotating ring-disk electrode and studied for both the O2 evolution and O2 reduction reactions in 1 M KOH solution and O2-saturated 1 M KOH solution, respectively. Rutile Nb0.05Ti0.95O2 (1050 °C) powder was chosen owing to its larger overpotential for H2 evolution (detrimental to the performance of bifunctional electrodes) and its low and stable anodic activity, whereas anatase Nb0.05Ti0.95O2 (450 °C) powder was mainly selected due to its higher specific surface area. The results have shown that the Nb0.05Ti0.95O2 powders are more suitable than Vulcan XC72R for use as a conductive support material, based on the higher electrode intrinsic current densities recorded for O2 evolution and reduction reactions.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Electroanalytical Chemistry - Volume 611, Issues 1–2, 15 December 2007, Pages 67–79
نویسندگان
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