Measuring individual overpotentials in an operating solid-oxide electrochemical cell

We use photo-electrons as a non-contact probe to measure local electrical potentials in a solid-oxide electrochemical cell. We characterize the cell in operando at near-ambient pressure using spatially-resolved X-ray photoemission spectroscopy. The overpotentials at the interfaces between the Ni and Pt electrodes and the yttria-stabilized zirconia (YSZ) electrolyte are directly measured. The method is validated using electrochemical impedance spectroscopy. Using the overpotentials, which characterize the cell's inefficiencies, we compare without ambiguity the electro-catalytic efficiencies of Ni and Pt, finding that on Ni H_2O splitting proceeds more rapidly than H2 oxidation, while on Pt, H2 oxidation proceeds more rapidly than H2O splitting.Comment: corrected; Phys. Chem. Chem. Phys., 201

Aqueous Solution Preparation, Structure, and Magnetic Properties of Nano-Granular ZnxFe3−xO4 Ferrite Films

This paper reports a simple and novel process for preparing nano-granular ZnxFe3−xO4 ferrite films (0 ≤ x ≤ 0.99) on Ag-coated glass substrates in DMAB-Fe(NO3)3-Zn(NO3)2 solutions. The deposition process may be applied in preparing other cations-doped spinel ferrite films. The Zn content x in the ZnxFe3−xO4 films depends linearly on the Zn2+ ion concentration ranging from 0.0 to 1.0 mM in the aqueous solutions. With x increasing from 0 to 0.99, the lattice constant increases from 0.8399 to 0.8464 nm; and the microstructure of the films changes from the non-uniform nano-granules to the fine and uniform nano-granules of 50–60 nm in size. The saturation magnetization of the films first increases from 75 emu/g to the maximum 108 emu/g with x increasing from 0 to 0.33 and then decreases monotonously to 5 emu/g with x increasing from 0.33 to 0.99. Meanwhile, the coercive force decreases monotonously from 116 to 13 Oe

ニッケル サンカブツ ハクマク オヨビ マンガン サンカブツ ハクマク : スイヨウエキ カラ ノ シンキ チョウセイホウ ト エレクトロクロミズム ノ トクセイ カイセキ

京都大学0048新制・論文博士博士(工学)乙第10669号論工博第3591号新制||工||1215(附属図書館)UT51-2001-F467(主査)教授 西本 清一, 教授 小久見 善八, 教授 垣 内隆学位規則第4条第2項該当Doctor of EngineeringKyoto UniversityDA