High performance catalysts based on Fe/N co-doped carbide-derived carbon and carbon nanotube composites for oxygen reduction reaction in acid media

The key issue of modern electrochemical technology is clean energy production and storage. Proton exchange membrane fuel cells (PEMFC)offer a way to produce electricity from hydrogen, but are hindered by the sluggish reduction of oxygen into water on the cathode, which requires Pt/C catalysts. Iron-nitrogen-carbon (Fe-N-C)catalysts have been shown in recent years to be viable alternatives. Here, we present highly performing Fe-N-C catalysts based on composite materials synthesised from carbide-derived carbon (CDC)and carbon nanotubes (CNT). B₄C, Mo₂C and TiC, which yield CDC materials with different porosity were chosen as the starting carbides, which are then doped with Fe, N and composited with CNTs using ball-milling and pyrolysis. 1,10-phenanthroline (Phen)and dicyandiamide (DCDA)serve as the nitrogen sources and Fe(II)acetate as the iron source. The catalyst derived from TiC shows a remarkable half-wave potential for oxygen reduction of 0.8 V vs RHE, which shifts negative 36 mV during 5000 potential cycles at 70 °C, while the composite material derived from it is more stable with a shift of only 15 mV during the same period.