Perovskite Oxides Electrodes for Alkaline Oxygen Evolution Reaction

Designing electrode materials for oxygen evolution reaction (OER) and for oxygen reduction reaction (ORR) is crucial for the development of renewable energy technology devices, such as water electrolyzers and fuel cells [1]. Alkaline water electrolysis is seen as an eco-friendly process for large-scale production of hydrogen required for hydrogen economy. However, the efficiency of water electrolysis in practice is limited by the large overpotential necessary to drive OER, resulting in high cost of the process and produced hydrogen.

There are few literature reports on OER at perovskite-based electrodes where different carbon supporting materials were often used for increase of active surface area and conductivity [1-3]. The aim of this study was to examine the intrinsic activity of perovskite materials.

Therefore, six different perovskite oxides were used for preparation of electrodes with no carbon support, to be studied for OER in alkaline media. These were La_0.8Sr_0.2Fe_0.8Co_0.2O₃, La_0.7Sr_0.3MnO₃, La₂NiO₄, La_1.9Pr_0.1CuO₄, La_1.8Pr_0.2NiO₄ and La_1.9Sr_0.1NiO₄. OER studies were performed using cyclic voltammetry (CV) and linear scan voltammetry (LSV) in potassium hydroxide (KOH) solution. Main reaction parameters, namely Tafel slopes, charge transfer coefficients, exchange current densities, and activation energies were determined from the LSV data. Influence of operating parameters, specifically electrolyte composition and temperature, was also investigated.

First results indicated the highest activity of La_1.9Sr_0.1NiO₄ for the OER in the studied temperature range (25 – 85 ºC).

References

[1] M. Risch, K. A. Stoerzinger, S. Maruyama, W. T. Hong, I. Takeuchi, Y. Shao-Horn, J. Am. Chem. Soc. 136 (2014) 5229 − 5232.

[2] C. Jin, X. Cao, L. Zhang, C. Zhang, R. Yang, J. Power Sources 241 (2013) 225 – 230.

[3] R. A. Rinc, E. Ventosa, F. Tietz, J. Masa, S. Seisel, V. Kuznetsov, W. Schuhmann, ChemPhysChem 15 (2014) 2810 – 2816.