Hydrogen Evolution Activity of Ruthenium Phosphides Encapsulated in Nitrogen‐ and Phosphorous‐Codoped Hollow Carbon Nanospheres

Abstract RuP x nanoparticles (NPs) encapsulated in uniform N,P‐codoped hollow carbon nanospheres (RuP x @NPC) have been synthesized through a facile route in which aniline–pyrrole copolymer nanospheres are used to disperse Ru ions followed by a gas phosphorization process. The as‐prepared RuP x @NPC exhibits a uniform core–shell hollow nanospherical structure with RuP x NPs as the core and N,P‐codoped carbon (NPC) as the shell. This strategy integrates many advantages of hollow nanostructures, which provide a conductive substrate and the doping of a nonmetal element. At high temperatures, the obtained thin NPC shell can not only protect the highly active phase of RuP x NPs from aggregation and corrosion in the electrolyte but also allows variation in the electronic structures to improve the charge‐transfer rate greatly by N,P codoping. The optimized RuP x @NPC sample at 900 °C exhibits a Pt‐like performance for the hydrogen evolution reaction (HER) and long‐term durability in acidic, alkaline, and neutral solutions. The reaction requires a small overpotential of only 51, 74, and 110 mV at 10 mA cm −2 in 0.5 m H 2 SO 4 , 1.0 m KOH, and 1.0 m phosphate‐buffered saline, respectively. This work provides a new way to design unique phosphide‐doped carbon heterostructures through an inorganic–organic hybrid method as excellent electrocatalysts for HER.