Nitrogen, phosphorus co-doped mesoporous carbon materials as efficient catalysts for oxygen reduction reaction

Abstract

Carbon, phosphorus or nitrogen-doped carbon and nitrogen, and phosphorus co-doped carbon materials were successfully synthesized. The scanning electron microscopy and transmission electron microscope indicated that the samples exhibited three-dimensional layered structure. While the X-ray diffraction and Raman results suggested that the samples were typical carbon materials with high purity, besides, the nitrogen adsorption-desorption isotherm results showed that the nitrogen, phosphorus co-doped carbon material had the highest specific surface area of 2346.2 m2 g−1 with uniform mesoporous (3.8 nm) and considerable pore volume (0.69 cm3 g−1). The cyclic voltammetry, electrochemical impedance spectra, liner sweep voltammetry, and chronoamperometry were tested in oxygen-saturated 0.1 M KOH solution. The electrochemical tests suggested that the nitrogen, phosphorus co-doped carbon material had a positive onset potential (0.92 V), half-wave potential (0.81 V), low resistance (73 Ω), and low Tafel slope (70 mV/decade) at low current region. More importantly, the oxygen reduction reaction was a 4-electron pathway with excellent methanol tolerance.