Bifunctional Transition Metal Oxide-Based Oxygen Electrode Catalysts for Unitized Reversible Fuel Cells

Abstract

While the global warming and environmental pollutions have been emerged as international issues, hydrogen, which is renewable and sustainable energy source has received extensive attentions. Especially, unitized reversible fuel cells (URFCs) are considered as a prospective electrochemical energy conversion device due to their high energy efficiency and non-polluting system [1]. However, sluggish electrochemical kinetics and overpotential loss for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in both electrodes are still the biggest technical obstacles for entering into the real markets [2]. Until now, platinum-based noble metals such as platinum, iridium, and their alloys have been used for OER and ORR catalysts because of their high electrocatalytic activity [3]. However, the main weaknesses of these materials are low durability, low bifunctionality, and high price [4, 5]. In order to overcome these barriers, non-precious transition metal oxide-based material have regarded as promising alternative for bifunctional electrocatalysts due to their low price and high durability [6]. In this study, to increase intrinsic property and electrical conductivity of catalysts for OER and ORR, doping of other transition metals with various high surface area carbonaceous materials as a supporting material is adopted. The synthesized catalysts are analyzed by various physicochemical and electrochemical tools [7. 8]. References Y. Liang, Y. Li, H. Wang, J. Zhou, J. Wang, T. Regier, H.Dai, Nat. Mater. 10, 780-786 (2011).K. Fominykh, P. Chernev, I. Zaharieva, J. Sicklinger, G. Stefanic, M. Doblinger, A. Muller, A. Pokharel, S. Bocklein, C. Scheu, T. Bein, and D. F. Rohifing, ACS. Nano., 5, 5180 (2015).S. Anantharaj, P. E. Karthik and S. Kundu, J. Mater. Chem. A., 3, 24463 (2015).Q. Han, N. Chen, J. Zhang and L. Qu, Mater. Horiz., 4, 832 (2017).A. C. Pebley, E. Decolvenaere, T. M. Pollock, and M. J. Gordon, Nanoscale., 9, 15070 (2017).Y.-F. Li, and A. Selloni, ACS Catal., 4, 1148 (2014).N.-I. Kim, Y.J. Sa, S.-H. Cho, I. So, K. Kwon, S.H. Joo, and J.-Y. Park, J. Electrochem. Soc., 163, F3020 (2016).I.-S. So, N.-I. Kim, S.-H. Cho, Y.-R. Kim, J. Yoo, Y. Seo, Y.-S. Seo, B. Park, K. Kwon, and J.-Y. Park, J. Electrochem. Soc., 163, F3041 (2016). Keywords: Oxygen evolution reaction; Oxygen reduction reaction; Bifunctional electrocatalysts; Unitized reversible fuel cell; Transition metal oxide.