Design of active Pt on TiO₂ based nanofibrous cathode for superior PEMFC performance and durability at high temperature

Oxygen reduction reaction (ORR) activity and stability of the cathode catalyst are important issues for practical applications, which should be even considered for the materials in high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). To improve these properties, modification of the catalyst electronic structure and finding durable supports can be a good approach. In this study, we synthesized a noble nanofibrous composite electrode which consist of carbon nanotube (CNT)-winded Pt/TiO₂ nanofiber (CNT-Pt/TiO₂). Our approach takes advantages of the electrochemical conductivity of CNF as well as better stability from the corrosion resistivity of TiO₂ and strong metal-support interaction (SMSI) between the Pt nanoparticles and TiO₂ nanofibers for less Pt dissolution. We also found that the Pt electronic state can be changed by an interaction with neighbouring CNT and TiO₂, resulting a decrease of Pt d-band vacancy for enhanced catalytic activity. Furthermore, nanofibrous structure with a unique 3D pore structure provides higher surface area for additional improvements of the mass transfer. These results reveal that the CNT-Pt/TiO₂ nanofiber based electrode shows enhanced performance with the maximum power density of 567 mW cm⁻² compare to commercial Pt/C (461 mW cm⁻²) with a significant durability at harsh conditions of 120 °C and RH 40%.