Effects of the Substitution of Β-Site Ion on Oxygen Reduction Electrode Properties of Pb₂Ru₂O_{7- δ} in Aqueous Solutions

Abstract:

The activities of the pyrochlores Pb2Ru2-xMxO7-δ (M=Mn,Fe,Co,Ni)[PRM(0x)] toward electrochemical oxygen reduction (EOR) were examined in 0.1 M KOH and 0.05 M H2SO4 aqueous solutions. The onset voltage (Vo) and the efficiency (E4) of 4-electron reduction of oxygen for PRM(0x) were evaluated by semi-steady state voltammetry with rotating ring-disk electrodes. In PRM01, the order of the EOR activities was PRMn01 > PRCo01 > PRNi01 > PRFe01 in both solutions. This was consistent with the variation of the lattice parameters, i.e. PRM01 with a smaller lattice parameter showed higher EOR activity. In addition, PRMn05 showed higher EOR activity than PRMn01. The onset voltages Vo were 0.95 and 0.50 V vs. reversible hydrogen electrode in 0.1 M KOH and 0.05 M H2SO4, respectively, while E4 was almost 100 % in both solutions. These results indicate that the EOR activity of PRM(0x) depends on the incorporated metal ions on the B-sites and their contents.

• Periodical: Key Engineering Materials (Volume 350)
• Pages: 171-174
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.350.171
• Online since: October 2007
• Authors: Kenji Yoshihara, Yoshinobu Saito, Morihiro Saito, Jun Kuwano, Hidenobu Shiroishi
• Keywords: Acid Solution, Alkaline Solution, Oxygen Reduction, Pyrochlore, Substitution

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