Pt Nanorod Catalysts Supported on Nb-SnO 2 for Polymer Electrolyte Fuel Cells Toward the Application of Heavy-Duty Vehicles

Current-voltage performance and durability in polymer electrolyte fuel cells should be improved further toward the application of heavy-duty vehicles. Pt and Pt-alloy catalyst supported on the porous carbon is one of the essential catalysts, and is in progress to obtain these performances. One of the other interesting catalysts is the Pt catalysts supported on doped SnO 2 (Pt/Nb-SnO 2 ) without carbon additives. The durability (startup/shutdown, load cycling) and oxygen reduction reaction (ORR) activity of the Pt/Nb-SnO 2 are superior to those of commercial Pt catalysts supported on carbon black (Pt/CB) etc. [1-8] 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 particle and the gas diffusion pathways via the open pores surrounded by particles. The meta-support interaction at the interface between Pt and these oxide supports affects the electronic state of the Pt catalysts, which enhance the catalytic activity and durability [5] . The IV performance of the single cell using the Pt /Nb-SnO 2 cathode catalyst layers at operating temperatures from 80 o C to 120 o C approaches the I-V performance at the end of life of NEDO target. The Pt/Nb-SnO 2 is one of the candidate catalysts for application of the heavy-duty vehicles operating at wide-temperature range (< 120 o C) [9] . Acknowledgments This work was partially supported by funds for the project 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. Referencies 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, A. 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 , 044522 (2022).