Nitrogen, sulfur and phosphorus-codoped carbon with a tunable nanostructure as an efficient electrocatalyst for the oxygen reduction reaction

Abstract

Novel types of N,S,P-codoped carbons with varied nanostructures are developed as efficient and stable electrocatalysts for the oxygen reduction reaction (ORR). The carbon catalysts were facilely prepared using poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) nanospheres as single precursors through a pyrolysis procedure in the presence or absence of melamine. The as-prepared microporous carbon nanospheres NSP-PC-1 with a high surface area (967 m² g⁻¹) exhibit a significantly enhanced ORR catalytic activity compared to their solely N-doped counterpart (N-PC-1), suggesting the remarkable contribution of additional S,P-doping on the ORR performance. More importantly, the as-prepared mesoporous carbon nanosheets NSP-PC-2 with a moderately high surface area (613 m² g⁻¹) and comparable overall NSP content show greatly improved ORR catalytic activity relative to that of NSP-PC-1, which is even slightly superior to that of commercial Pt/C catalysts. The excellent performance of NSP-PC-2 is mainly attributed to its proper N,S,P-codoping as well as advanced structural features.