Binary transition metal and ZIF-8 functionalised polymer-derived ceramic catalysts for high temperature PEM fuel cell cathode

For addressing the clean energy transition, the high-temperature proton exchange membrane fuel cells (HT-PEMFC) are attractive energy conversion devices for the long-range and heavy-duty vehicles, auxiliary power units, and aviation applications. One current drawback inhibiting HT-PEMFC commercialisation is the need for non-precious metal catalyst (NPMC) for oxygen reduction reaction (ORR) at the cathode. Here we propose the polymer derived ceramics (PDC) based material silicon oxycarbide (SiOC) with double transition metal (TM) doping and N-functionalisation for the NPMC preparation. The catalysts prepared with zeolitic imidazolate framework-8 (ZIF-8) as a N source exhibited high specific surface area, hierarchical porosity, and presence of TM (alloy) nanoparticles together with atomically dispersed TMs. The highest activity towards the ORR was observed in the case of Fe/Co containing and acid leached catalyst material (CoFe-N-SiOCa) exhibiting the highest long-term durability in 0.5 M H₃PO₄ solution and the best performance during the GDE testing in conc. H₃PO₄ at 160 °C. During HT-PEMFC testing, the open circuit voltage of 768 mV and power density at 100 mA cm⁻² of 34 mW cm⁻² with CoFe-N-SiOCa cathode were registered.