Nitrogen and Phosphorus Dual-Doped Silicon Carbide-Derived Carbon/Carbon Nanotube Composite for the Anion-Exchange Membrane Fuel Cell Cathode
Iris Palm, Elo Kibena‐Põldsepp, Marek Mooste, Jekaterina Kozlova, Maike Käärik, Arvo Kikas, Alexey Treshchalov, Jaan Leis, Vambola Kisand, Aile Tamm, Steven Holdcroft, Plamen Atanassov, Kaido Tammeveski
Abstract
Dual heteroatom (N,P)-doped catalysts based on the composite of silicon carbide-derived carbon (SiCDC) and carbon nanotubes (CNTs) or solely CNTs were prepared for oxygen reduction reaction (ORR) using melamine phosphate as nitrogen and phosphorus precursors. The half-cell test conducted by the rotating ring-disk electrode method exhibited a high ORR electrocatalytic activity for N,P-SiCDC/CNT with an onset potential of 0.91 V and a half-wave potential of 0.80 V in alkaline solution. Similar ORR results were obtained with N,P-CNT. The dual heteroatom-doped SiCDC/CNT composite as a cathode catalyst exhibited an impressive peak power density of 538 mW cm–2 in an anion-exchange membrane fuel cell (AEMFC) test. The superior AEMFC performance of this catalyst could be attributed to (i) the high specific surface area along with hierarchical porosity (micro/mesopores) as revealed by the N2 physisorption analysis, (ii) high defect density (ID/IG = 1.54) determined by Raman spectroscopy analysis, and (iii) successful doping of N and P moieties into the carbon materials as revealed by X-ray photoelectron spectroscopy and scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy.