Hideo Daimon
Hideo Daimon
Doshisha University
Date: July 15, 2026
Time: 1000–1100h EDT
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In 2020, Toyota Motor Corporation launched the FC-EV of MIRAI-II, which adopted a mesoporous carbon of nano dendrite (MCND) support for the PtCo alloy catalyst nano particles (NPs) to suppress ionomer poisoning. Concurrently, the CNovel® MH-18 mesoporous carbon (MPC) support, mass-produced by TOYO TANSO (Osaka, Japan) was introduced. The characteristics of the MPC support differed significantly from those of the conventional Ketjen Black EC-600JD (KB-600JD) porous carbon support. The MPC support has a primary particle size of approximately 2 μm, whereas the primary particle size of KB-600JD is 40–50 nm. In addition, the MPC support consists of isolated particles that lack the chain-like structure seen in KB-600JD. The unique pore structure of the MPC support, characterized by the coexistence of highly interconnected mesopores (2–6 nm) and macropores, enables oxygen molecules to access the Pt catalyst NPs from all directions within the support. As a result, higher cell voltages are achieved in high-current-density regions compared to the Pt/KB-600JD catalyst.
The MPC support was ground to approximately 800 nm using a bead mill. Because grinding generates new surfaces on the MPC support, the ground material was heat treated in an Ar atmosphere at temperatures ranging from 1800°C to 2400°C to improve durability. The durability of the Pt/MPC (800 nm) catalyst was evaluated in membrane electrode assemblies (MEAs) using a triangular-wave potential cycle of 1.0 to 1.5 V vs. RHE. The Pt/MPC (800 nm) catalyst prepared with freshly milled MPC support exhibited higher durability than the Pt/KB-600JD catalyst. Although new surfaces were formed by bead milling, the purchased MPC (2 µm) had already undergone heat treatment at 1800°C in an Ar atmosphere during the final manufacturing process at TOYO TANSO. Catalyst durability increased with increasing heat-treatment temperature, and the Pt/MPC (800 nm) catalyst prepared with MPC support heat treated at 2400°C exhibited the highest durability under a triangular-wave potential cycle of 1.0–1.5 V vs. RHE.
XRD and HR-TEM analyses revealed further growth of the carbon (002) plane following heat treatment. N2 gas adsorption/desorption isotherms measured at 77 K indicated that the porosity of the MPC support decreased as heat-treatment temperature increased. The surface area of the freshly milled MPC support decreased from 1338 m²/g to 351 m²/g after heat treatment at 2400°C. Considering both catalyst durability and retention of MPC support porosity, a heat-treatment temperature in the range of 2000°C to 2200°C appears to be optimal.
Attend this webinar to learn about:
- The porosity of CNovel® MH-18 mesoporous carbon support;
- Why CNovel® MH-18 mesoporous carbon support exhibits high durability;
- Strategies for optimizing the performance of CNovel® MH-18 mesoporous carbon support in PEFCs.
Presenter
Hideo Daimon completed his MSc in Chemistry at Kwansei Gakuin University in 1984 and subsequently joined the Research and Development Department at Hitachi Maxell, Ltd. There, he conducted research on magnetic materials prepared via chemical routes; the friction and wear of thin-film magnetic recording media; protective coatings and lubricants for thin-film media; and electrodeposition and electroless plating of Ni and Ni-P films.
In 2000, Daimon began synthesizing PtFe, PtRu, and Pt nanoparticles for use in fuel cells. He moved to Doshisha University in 2010, where his research has focused on Pt and Pt-based catalysts for polymer electrolyte fuel cells (PEFCs), including Au@Pt- and Pd@Pt core-shell structured catalysts, as well as PtCo alloy catalysts. Currently, his research centers on mesoporous carbon supports designed to enhance the performance and durability of PEFCs used in fuel cell electric vehicles (FCEVs).
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