Silicon carbide-derived carbon electrocatalysts dual doped with nitrogen and phosphorus for the oxygen reduction reaction in an alkaline medium
Iris Palm, Elo Kibena‐Põldsepp, Uno Mäeorg, Jekaterina Kozlova, Maike Käärik, Arvo Kikas, Jaan Leis, Vambola Kisand, Aile Tamm, Kaido Tammeveski
Abstract
In this study, two compounds (melamine phosphate and hexachlorocyclotriphosphazene) were used as nitrogen and phosphorus precursors to dope silicon carbide-derived carbon (SiCDC) with nitrogen and phosphorus moieties. The successful heteroatom doping was confirmed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy/energy-dispersive X-ray (SEM-EDX) analysis. The resulting N,P-doped SiCDC exhibited high oxygen reduction reaction (ORR) performance in alkaline conditions in terms of onset and half-wave potential, slightly surpassing the ORR activity of solely N-doped SiCDC. Since N2 physisorption showed that the porosity parameters and specific surface area of N,P-doped SiCDC (in which melamine phosphate was used as a N and P precursor) were rather similar to that of N-doped SiCDC, the improvement in the ORR activity of N,P-doped SiCDC could be attributed to the new ORR-active sites produced by the introduction of nitrogen and phosphorus moieties into the SiCDC.