Synthesis and electrocatalytic performance of N-doped ordered mesoporous carbon-Ni nanocomposite

Highly ordered mesoporous carbon co-modified with Ni-N can be prepared via homogeneous phase route as well as dual-phase route, named as Ni-N-OMC-1 and Ni-N-OMC-2 respectively. Triblock copolymer Pluronic F127 were employed as the template agent, urea as the N precursor, NiCl₂ as the Ni source and resorcinol-formaldehyde resin as the carbon precursor. X-ray diffraction (XRD), Raman, and transmission electron microscope (TEM) showed that nickel particles dispersed in the carbon matrix in forms of metal nickel, in situ catalyzing the graphitization of amorphous carbon. X-ray photoelectron spectroscopy (XPS) revealed that urea existed in four different N species after heat treatment: sp₃ nitrogen atoms bonded to carbon atoms, pyridine-like N, sp₂ nitrogen atoms bonded to carbon atoms and quaternary-N atoms. The co-modification of nitrogen and nickel changed the physicochemical properties of carbon matrix, thus making for the loading and dispersing of Pt. Pt nanoparticles deposited on Ni-N-OMC-1 nanocompsite showed excellent electrocatalytic activity. The electrochemical active surface area of hydrogen oxidation was 138.53 m²∙g^-1 and the limiting current density in ORR was 5.32 mA∙cm^-2, which indicated higher electrocatalytic ability than that of the commercial 20% Pt/C catalysts (4.49 mA∙cm^-2, 96.98 m²∙g^-1).