Oxygen Reduction Electrode Properties of Pyrochlores Ln2Ru2O7-δ(Ln=Pr, Nd, Sm) in Aqueous Solutions


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The activity of electrochemical oxygen reduction (EOR) for the pyrochlores Ln2Ru2-XO7-δ (Ln=Pr,Nd,Sm) [LnR] were examined in 0.1 M KOH aqueous solution at 70oC. The onset voltage (Vo) of the oxygen reduction current and the efficiency (E4) of 4-electron reduction of oxygen were evaluated by semi-steady state voltammetry with rotating ring-disk electrodes. PrR with the highest EOR activity showed Vo = ~ 0.85 V vs. reversible hydrogen electrode and E4 values above 80 %. Their Vo and E4 values show that LnR containing Ln with a smaller atomic number has a higher EOR activity, i.e. the order of the activity is PrR > NdR > SmR. This was in good agreement with that of the lattice parameters of LnR. These results indicate that the EOR activity of LnR depends on the kind and/or the size of the lanthanide metal ion on the A-site. PrR and NdR exhibited higher E4 values than known excellent Pb2Ru2O7-δ electrocatalyst containing toxic Pb.



Edited by:

K. Katayama, K. Kato, T. Takenaka, M. Takata and K. Shinozaki




Y. Saito et al., "Oxygen Reduction Electrode Properties of Pyrochlores Ln2Ru2O7-δ(Ln=Pr, Nd, Sm) in Aqueous Solutions", Key Engineering Materials, Vol. 350, pp. 167-170, 2007

Online since:

October 2007




[1] T. Takeda, R. Kanno, Y. Kawamoto and Y. Takeda, J. Electrochem. Soc., 147 (2000), p.1730.

[2] P. Fabry and E. Siebert, The Handbook of Solid State Electrochemistry, Edited by P. J. Gelling and H. J. M. Bouwmeester, (Boca Raton, Florida, 1996), pp.329-369 and pp.407-553.

[3] K. S. Goto, Solid State Electrochemistry and Its Application to Sensors and Electronic Devices, (Elsevier, Amsterdam, 1988).

[4] H. S. Horowitz, J. M. Longo and J. T. Lewandowski, US Patent 4 129 525 (1978).

[5] J. -M. Zen, R. Manoharan and J. B. Goodenough, J. Appl. Electrochem., 22 (1992), p.140.

[6] I. S. Shaplygin, I. I. Prosychev and V. B. Lazarev, Russian J. Inorg. Chem., 34 (1989), p.300.

[7] T. Kawabata, S. Koga, T. Hijii, J. Kuwano and Y. Saitou, Extended Abstracts of the 21st Electronics Division Meeting, (2001), p.87.

[8] Y. Yoshihara, T. Chuma, M. Saito, J. Kuwano and H. Shiroishi, Key Eng. Mater., 320 (2006), p.235.

[9] J. B. Goodenough, R. Manoharan and M. Paranthaman, J. Am. Chem. Soc., 112 (1990), p. (2076).

[10] A. M. Kuznetsov and J. Ulstrup, Electrochem. Acta., 45 (2000).