Interface effects of platinum nanoparticles and titanium compounds for the development of high-performance and durable polymer electrolyte membrane fuel cells

Platinum nanoparticles (Pt-NPs) supported on carbon (Pt/C) are representative catalysts for polymer electrolyte membrane fuel cells (PEMFCs). Due to dissolution and agglomeration of Pt-NPs under fuel cell operating conditions, extensive research is being conducted to enhance stability through modification of support materials. In this study, we synthesized controlled titanium-based oxide and nitride NPs incorporated into carbon supports (TiO₂-C and TiN-C) as support materials. The mass activity of platinum catalysts supported on titanium nitride supports (Pt/TiN-C) for oxygen reduction reaction (ORR) were determined to be 0.32 A mg_Pt⁻¹ at 0.9 V_RHE, exceeding that of commercial Pt/C catalyst (0.21 A mg_Pt⁻¹ at 0.9 V_RHE). In single cell tests, the performance of Pt/TiN-C electrodes exhibited higher current densities of 0.358 A cm⁻² at 0.75 V compared to commercial Pt/C electrodes (0.238 A cm⁻² at 0.75 V). Remarkably, the Pt/TiN-C electrodes (33.5 % current density and 34.6 % power density reduction at 0.75 V) showed higher performance and durability than commercial Pt/C electrodes (Reduction of 67.2 % in current density and 70.5 % in power density at 0.75 V) after accelerated degradation tests. The enhanced performance and durability of Pt/TiN-C was attributed to the formation of interfaces between TiN and Pt NPs, providing appropriate oxygen adsorption energy and improving Pt stability under acidic conditions. This study provides significant insights for advanced electrode architecture of practical fuel cell applications.