Near ambient pressure X-ray photoelectron - and impedance spectroscopy study of NiO - Ce0.9Gd0.1O2-? anode reduction using a novel dual-chamber spectroelectrochemical cell

By Nurk, Gunnar; Kooser, Kuno; Urpelainen, Samuli; K
Published in Journal of Power Sources 2018

Abstract

This paper reports an experimental study, where the reduction of NiO-GDC to Ni-GDC is monitored using high temperature (HT) near ambient pressure (NAP) X-ray photoelectron spectroscopy (XPS) in combination with simultaneous impedance spectroscopy (IS). The experiment is carried out using a dual chamber (DC)-HT-NAP-XPS cell designed for membrane electrode studies. The dual chamber measurement cell enables adequate electrochemical feedback, i.e. the possibility of measuring the working electrode potential against a Pt reference electrode in a well-known environment (pO2 = 0.2 bar) and of monitoring the pO2 value on the studied electrode through open circuit voltage (OCV) measurements. Simultaneous changes of electrode impedance and O 1s, Ce 4d and Ni 3p electron binding energies are observed and discussed. The shape of the O 1s photoelectron peak is significantly influenced by the equilibria of Ce4+ ? Ce3+ and Ni2+ ? Ni0, influenced by pO2, in analysis chamber.

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