Pt Catalysts Supported on Nb-SnO2/CeO2 for Polymer Electrolyte Fuel Cells Toward the Application of Heavy-Duty Vehicles

Highly durable and active cathode catalyst is required toward the wide spread use of polymer electrolyte fuel cells, such as heavy-duty vehicles. Pt supported on porous carbon is one of the essential catalysts, and is considered to improve the durability and activity. One of the other interesting catalysts is the Pt catalysts supported on doped SnO2 and CeO2 (Pt/M-SnO2, M = Nb, Zr) without carbon additives. The durability (startup/shutdown, load cycling) and oxygen reduction reaction (ORR) activity of the Pt/M-SnO2 is superior to those of commercial Pt catalysts supported on carbon black (Pt/CB) etc. [1-8]. The Pt/M-CeO2 also supply the new function of scavenging effect to mitigate the membrane degradation even though the higher temperature operation over 100oC. These catalysts have a unique carbon-like microstructure of a fused-aggregate network structure, which supply the essential function of the electronically constructing pathways via necking of each support particles and the gas diffusion pathways via the open pores surrounded by particles. The interface between Pt and these oxide supports also has an essential electronic interaction as shown in the catalyst design concept (Fig. 1)[5]. The IV performance of the single cell using the Pt /Nb-SnO2 cathode catalyst layers and Pt/Zr-CeO2 anode ones at operating temperatures from 80oC to 120oC is quite high to approach the NEDO target performance with keeping high durability. The catalyst is considered to have possibilities for application of the heavy-duty vehicles operating at wide-temperature range (< 120oC)[9]. Acknowledgments This work was partially supported by funds for the project “Electrolytes, Catalysts and Catalyst layers with Extraordinary Efficiency, power and Durability for PEFCs-2030 (ECCEED’30) from the New Energy and Industrial Technology Development Organization (NEDO) of Japan, and JSPS KAKENHI Grant Number (23H02059) from the Ministry of Education, Culture, Sports, Science and Technology. References K. Kakinuma, M. Uchida, T. Kamino, H. Uchida, M. Watanabe, Electrochim. Acta, 56, 2881 (2011). Y. Senoo, K. Kakinuma, M. Uchida, H. Uchida, S. Deki, M. Watanabe, RSC Adv., 6, 321800 (2014). Y. Chino, K. Taniguchi, Y. Senoo, K. Kakinuma, M. Watanabe, M. Uchida, J. Electrochem. Soc., 162, F736 (2015). K. Kakinuma, R. Kobayashi, A. Iiyama, M. Uchida, J. Electrochem. Soc., 165, J3083 (2018). K. Kakinuma, K. Suda, R. Kobayashi, T. Tano, C. Arata, I. Amemiya, S. Watanabe, M. Matsumoto, H. Imai, Iiyama, M. Uchida, ACS Appl. Mater. Interfaces 11, 34957 (2019). K. Kakinuma, M. Hayashi, T. Hashimoto, A. Iiyama, M. Uchida, ACS Appl. Energy Mater., 3, 6922 (2020). G. Shi, T. Tano, D.A. Tryk, A. Iiyama, M. Uchida, K.Kakinuma, ACS Catal., 11, 5222 (2021). G.Shi, T.Tano, D.A.Tryk, A.Iiyama, M.Uchida, Y.Kuwauchi, A.Masuda, K.Kakinuma, J. Catal., 407, 300 (2022). K. Kakinuma, H. Taniguchi, T. Asakawa, T. Miyao, M. Uchida, Y. Aoki, T. Akiyama, A. Masuda, N. Sato, A. Iiyama J. Electrochem. Soc. 169 (2022) 044522. Figure 1