High−performance silica nanosheet/carbon black supported platinum catalyst in high−temperature proton exchange membrane fuel cells

Current catalysts for high-temperature proton exchange membrane fuel cells (HT-PEMFCs) are challenged by limited three−phase boundaries and electrochemical active surface area (ECSA). In response, hybrid silica nanosheet (SN) and carbon black (CB) supported Pt catalysts were synthesized. To enhance the electrical conductivity of the SN, the surface was coated with zeolitic imidazolate framework−8 and then carbonized to prepare carbon coated SN (CSN). The hybrid catalyst with a SN: CB weight ratio of 2:3 (Pt/SN₂−CB₃) retained around 95% of the ECSA even after 18000 cycles of accelerated stress test. Furthermore, Pt/CSN₂−CB₃ showed a superior peak power density of 320 mW cm⁻², compared with 283 mW cm⁻² for Pt/SN₂−CB₃ and 237 mW cm⁻² for Pt supported on CB (Pt/CB). Benefiting from their hydrophilicity and surface hydroxyl groups, SN and CSN could retain phosphoric acid (PA), thereby decreasing the PA absorption on catalyst surface, evidenced by improved ECSA and performance. Techno-economic analyses suggest a ∼30% reduction in cell production cost using the hybrid catalysts compared to bare CB case. This work demonstrates that the scalable, low-cost, and recyclable Pt/CSN₂−CB₃ catalyst can enhance HT-PEMFC performance and accelerate the integration of hydrogen fuel cells into renewable energy systems.