Various perovskites and their related structures have intensely studied for applications in solar cell, fuel cell, water splitting device and metal air battery, in part because of their flexibility in the choice of compositions, including the earth-abundant elements and non-noble metals.1-4 The change in composition will result in different electronic structures of catalysts. Various studies suggest the electron configuration of B-site metal ion is very important for electrocatalytic activity in oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). In this presentation, we report a new class of high performance ordered oxygen-deficient perovskite oxide (A2B2O5) electrocatalysts with nanocrystalline structure.5 We hypothesize that oxygen vacancy should also play an important role and is a structural factor to facilitate the OER kinetics. We show that oxygen deficient perovskite, Ca2Mn2O5, can catalyze the generation of oxygen gas at ~1.50 V versus (vs) reversible hydrogen electrode (RHE) electrochemically in alkaline media, and reach an OER mass activity of 30.1 A/g at 1.70 V (vs RHE). Ca2Mn2O5 also shows higher OER activity than perovskite CaMnO3, suggesting that oxygen-deficient perovskite A2B2O5 has the potential to become a new class of high performance electrocatalysts for rechargeable metal-air battery as well as in water splitting. (1) Takeguchi, T.; Yamanaka, T.; Takahashi, H.; Watanabe, H.; Kuroki, T.; Nakanishi, H.; Orikasa, Y.; Uchimoto, Y.; Takano, H.; Ohguri, N.; Matsuda, M.; Murota, T.; Uosaki, K.; Ueda, W. J. Am. Chem. Soc. 2013, 135, 11125. (2) Savinell, R. F. Nat. Chem. 2011, 3, 501. (3) Lee, M. M.; Teuscher, J.; Miyasaka, T.; Murakami, T. N.; Snaith, H. J. Science 2012, 338, 643. (4) Vojvodic, A.; Norskov, J. K. Science 2011, 334, 1355. (5) Kim, J.; Yin, X.; Tsao, K.-C.; Fang, S.; Yang, H. J. Am. Chem. Soc. 2014, published.

Role of oxygen vacancy in nanocrystalline perovskite oxides for electrochemical reactions

249th National Meeting (2015)

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