Electrochemical deposition of nanocatalysts for the catalytic activity improvement of composite oxide electrodes for solid oxide fuel cells

Abstract

Solid oxide fuel cells are devices that directly convert the chemical energy of hydrogen and oxygen into electrical energy, and are attracting attention for their high efficiency and eco-friendliness. Since the recent research trend is to lower the operating temperature of the device, there is a considerable demand for a way to effectively introduce a catalyst to overcome the poor electrochemical activity of the lanthanum strontium manganite–yttria-stabilized zirconia (LSM-YSZ) composite electrode. Herein, I present an electrochemical deposition method that fabricating a PrOx overlayer significantly improves the catalytic activity of composite electrodes with only a short process of less than 4 min, even in an ambient environment. Moreover, it does not require additional processes such as heat treatment. The PrOx-coated electrode exhibits a decrease in initial polarization resistance compared to the bare, and maintained an oxygen reduction reaction characteristic by more than 10 times even after about 400 h of operation at 650 °C. Transmission line model analysis with impedance spectra describes how PrOx improves the reactivity of the oxygen reduction reaction of composite electrodes. Finally, I demonstrate that a two-element material, (Pr, Ce)Ox, was electrochemically deposited. Electrochemical deposition considerably improves the catalytic properties of the cathode via a concise and straightforward process.