Microwave-Assisted Synthesis of Nitrogen and Phosphorus Co-Doped Mesoporous Carbon and Their Potential Application in Alkaline Fuel Cells

A simple, highly efficient, and rapid method for the synthesis of carbon microspheres doped with both phosphorus and nitrogen using microwaves is reported. The microwave assisted carbonization of a tannin-melaminehexamine polymer in the presence of polyphosphoric acid gives yields approaching 20.5% from the carbon precursor. The method uses no inert or reducing gas during the transformation. Elemental analysis from XPS studies confirmed the doping of nitrogen and phosphorus in a sp² hybridized carbon lattice. The content of phosphorus is 2.98% while that of nitrogen is 1.12%. The spheres are mesoporous with a BET surface area of ∼1000 m²/g and show significant promise in oxygen reduction reactions and are potential candidates for use in fuel cells.