Single-Step Electrophoretic Deposition of Non-noble Metal Catalyst Layer with Low Onset Voltage for Ethanol Electro-oxidation.
A single-step electrophoretic deposition (EPD) process is used to fabricate catalyst layers which consist of nickel oxide nanoparticles attached on the surface of nanographitic flakes. Magnesium ions present in the colloid charge positively the flake's surface as they attach on it and are also used to bind nanographitic flakes together. The fabricated catalyst layers showed a very low onset voltage (-0.2 V vs Ag/AgCl) in the electro-oxidation of ethanol. To clarify the occurring catalytic mechanism, we performed annealing treatment to produce samples having a different electrochemical behavior with a large onset voltage. Temperature dependence measurements of the layer conductivity pointed toward a charge transport mechanism based on hopping for the nonannealed layers, while the drift transport is observed in the annealed layers. The hopping charge transport is responsible for the appearance of the low onset voltage in ethanol electro-oxidation.
School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Ahmad
A
Ahmadi Daryakenari
Laboratory of Energy Science and Engineering, Department of Mechanical and Process Engineering, ETH Zurich , Leonhardstrasse 21, 8092 Zurich, Switzerland.
Davood
D
Hosseini
School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Ya-Lun
YL
Ho
School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Takumi
T
Saito
Institut des Nanotechnologies de Lyon (INL, CNRS UMR-5270), INSA Lyon, Lyon University , Villeurbanne, France.
Aleksandra
A
Apostoluk
Laboratory of Energy Science and Engineering, Department of Mechanical and Process Engineering, ETH Zurich , Leonhardstrasse 21, 8092 Zurich, Switzerland.
Christoph R
CR
Müller
School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Jean-Jacques
JJ
Delaunay
annealing treatment; electrophoretic deposition; ethanol electro-oxidation; hopping conduction; low onset voltage