Nitrogen and Phosphorus Dual-Doped Silicon Carbide-Derived Carbon/Carbon Nanotube Composite for the Anion-Exchange Membrane Fuel Cell Cathode

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 N-2 physisorption analysis, (ii) high defect density (I-D/I-G = 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.