Activation of oxygen reaction by praseodymium oxide film on platinum electrode in contact with YSZ electrolyte

Abstract

The method of impedancemetry is used to study electrochemical activity of platinum electrodes in contact with the solid electrolyte of YSZ (ZrO 2 +10 mol % Y 2 O 3 ). Electrodes are activated by small additives of pradeodymium oxide PrO x (0.1-0.3 mg/cm 2 ) by their impregnation by praseodymium nitrate solution with the further thermal treatment at 850°C and are studied in the cases when PrO x forms a film on the electrolyte and when no activator film is formed. The effect of the number of electrode activations on the electrochemical activity of platinum electrodes is studied.

Activation of Porous Pt Electrodes Deposited on YSZ Electrolyte by Nitric Acid Treatment

“…However, the polarization-induced activation is generally not durable; the electrode relaxation gradually occurs after interruption of polarization. The impregnation of porous electrodes with solutions of cerium or praseodymium nitrates, which decompose to the related oxides upon heating, was found to be effective for enhancement of the electrode performance [ 7 , 8 , 9 , 10 ]. Cerium nitrate solution was successfully used for activation of Ni-cermet SOFC anodes [ 7 , 8 ], whereas the impregnation with a solution of praseodymium nitrate was reported to activate cathodes such as In 2 O 3 [ 9 ] and Pt [ 10 , 11 ].…”

“…The impregnation of porous electrodes with solutions of cerium or praseodymium nitrates, which decompose to the related oxides upon heating, was found to be effective for enhancement of the electrode performance [ 7 , 8 , 9 , 10 ]. Cerium nitrate solution was successfully used for activation of Ni-cermet SOFC anodes [ 7 , 8 ], whereas the impregnation with a solution of praseodymium nitrate was reported to activate cathodes such as In 2 O 3 [ 9 ] and Pt [ 10 , 11 ]. The observed decrease of the electrode polarization resistance was explained by extension of the oxygen reduction/oxidation reaction area due to infiltration of the oxide particles into the porous electrode matrix [ 7 , 8 , 9 , 10 ].…”

“…Cerium nitrate solution was successfully used for activation of Ni-cermet SOFC anodes [ 7 , 8 ], whereas the impregnation with a solution of praseodymium nitrate was reported to activate cathodes such as In 2 O 3 [ 9 ] and Pt [ 10 , 11 ]. The observed decrease of the electrode polarization resistance was explained by extension of the oxygen reduction/oxidation reaction area due to infiltration of the oxide particles into the porous electrode matrix [ 7 , 8 , 9 , 10 ]. However, the salt solution impregnation results in decreasing the electrode porosity because of formation of oxide particles in the pores, which can lead to slowdown of gas diffusion and passivation of the electrode.…”