(Invited) High-Throughput Synthesis and Characterization of Fe-Based Oxygen Reduction Reaction Electrocatalysts and Perovskite Oxide Oxygen Evolution Electrocatalysts

Abstract

The sluggish kinetics of oxygen electrocatalysis and the resulting high overpotentials necessary to achieve useful current densities limit the development of promising technologies, such as fuel cells, water and carbon dioxide electrolyzers, and metal–oxygen batteries.1 The best catalysts for both the oxygen reduction and oxygen evolution reactions (ORR and OER, respectively) are based on precious, platinum group metals, such as platinum and iridium, leading to limitations in the cost effective implementation of these technologies.2,3 The development of alternative catalysts, with comparable or higher activity and durability to the PGM catalysts and derived from earth-abundant materials has thus been an active research area for decades.Incredible progress has been made over the past decade in increasing both the ORR activity and durability of PGM-free polymer electrolyte fuel cell (PEFC) cathode catalysts.4 Likewise, impressive progress has been made in developing PGM-free electrocatalysts for the OER in alkaline environments, with perovskite oxides showing activities comparable to PGM-based catalysts.5,6 The class of catalysts demonstrating the highest ORR activities are those typically denoted as “Fe-N-C” and synthesized by heat treating iron salts and zinc-based zeolitic imidazolate frameworks (ZIFs) and/or phenanthroline, as carbon and nitrogen sources, or by heat treating iron-substituted ZIFs. For this class of PGM-free materials, it has been determined that variables such as the metal and carbon-nitrogen macrocycle content, as well as the temperature and atmosphere in which the composites are heat treated are important in determining the activity and stability of the resulting catalysts.7-10 Changing these variables and testing their effect on the resulting catalyst properties is a time-consuming process and only a limited portion of the composition and temperature space have been explored for this broad class of materials. Perovskite oxides are a very broad class of materials with the general formula of ABO3, where the B site is occupied by smaller transition metal ions and the A site by larger cations which have 12-fold coordination with O.5 Both the A sites and B sites can be occupied by multiple metal ions, leading to an even more expansive design space for this class of materials.This presentation will describe the development and application of high-throughput methodology to accelerate exploration of the effects of composition and synthesis parameters on the activity of iron-carbon-nitrogen acidic electrolyte ORR electrocatalysts and perovskite oxide alkaline electrolyte OER catalysts. A multi-channel flow double electrode (m-CFDE) cell and other cells were designed and constructed for simultaneous screening the ORR and OER activity of multiple materials. The structural characterization of the materials using X-ray absorption spectroscopy (XAS) and correlation of the atomic structure with ORR and OER activity will be described, as will the high-throughput testing and optimization of the electrode composition using a 25-electrode array fuel cell hardware.11 References H. Yang, X. Han, A.I. Douka, L. Huang, L. Gong, C. Xia, H.S. Park, and B.Y. Xia, Adv. Func. Mater., 31 (2021) 2007602.B. Pivovar, Nature Catalysis, 2 (2019) 562.S. Thompson and D. Papageorgopoulos, Nature Catalysis, 2 (2019) 558.L. Osmieri, J. Park, D.A. Cullen, P. Zelenay, D.J. Myers, and K.C. Neyerlin, Curr. Opin. Electrochem., 25 (2021) 100627.J. Hwang, R.R. Rao, L. Giordano, Y. Katayama, Y. Yu, and Y. Shao-Horn, Science 358 (2017) 751.J. Suntivich, K.J. May, H.A. Gasteiger, J.B. Goodenough, Y. Shao-Horn, Science, 334 (2011) 1383.X. Wang, H. Zhang, H. Lin, S. Gupta, C. Wang, Z. Tao, H. Fu, T. Wang, J. Zheng, G. Wu, and X. Li, Nano Energy, 25 (2016) 110.H. Zhang, S. Hwang, M. Wang, Z. Feng, S. Karakalos, L. Luo, Z. Qiao, X. Xie, C. Wang, D. Su, Y. Shao, and G. Wu, J. Am. Chem. Soc., 139 (2017) 14143-14149.E. Proietti, F. Jaouen, M. Lefevre, N. Larouche, J. Tian, J. Herranz, and J.-P. Dodelet, Nature Comm. 2 (2011) 1.A. Zitolo, V. Goellner, V. Armel, M.-T. Sougrati, T. Mineva, L. Stievano, E. Fonda, and F. Jaouen, Nature Materials, 14 (2015) 937.J. Park and D.J. Myers, J. Power Sources, 480 (2020) 228801. AcknowledgementsThis work was supported by the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) under the auspices of the Electrocatalysis Consortium (ElectroCat). This work was also supported by DOE, Advanced Research Projects Agency-Energy (ARPA-E) under the DIFFERENTIATE program. This work utilized the resources of the Advanced Photon Source, a DOE Office of Science user facility operated by Argonne National Laboratory for DOE Office and was authored by Argonne, a DOE Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357.