A highly efficient electrocatalyst for oxygen reduction reaction: Spinel MnCo2O4 nanoparticles supported on three-dimensional Nitrogen-doped graphene material with interconnected hierarchical porous nanostructure

Abstract

• MnCo 2 O 4 /3DNG catalyst was prepared by hydrothermal method using 3DNG as support. • 3DNG with hierarchical porous structure possessed enrich the defects and expose more active sites. • MnCo 2 O 4 /3DNG with hierarchical porous structure contributed to improve mass transfer. • MnCo 2 O 4 /3DNG demonstrated excellent ORR activity and higher durability than 20% Pt/C. We designed and synthesized spinel MnCo 2 O 4 nanoparticles supported on three-dimensional nitrogen-doped graphene (NG) with interconnected hierarchical porous nanostructure, in which polymer (2, 5-benzimidazole) (ABPBI) was used as the nitrogen precursor and the carbon precursor. Unique properties of ABPBI including nitrogen-rich aromaticity and rigid plane molecule were conductive to form NG structures through the pyrolysis dehydrogenative and carbonization. The as-prepared MnCo 2 O 4 -3DNG with interconnected hierarchical porous graphene structure possessed enriched defects and more exposed active sites, accelerating mass transport and facilitating diffusion kinetics for better catalytic ORR performance. MnCo 2 O 4 -3DNG exhibited a higher half-wave potential (0.85 V vs RHE) than 20 wt% Pt/C (0.83 V vs RHE). Moreover, the accelerated durability test and i-t chronoamperometry of MnCo 2 O 4 -3DNG revealed more excellent durability than 20 wt% Pt/C. The electrochemical tests results demonstrated that MnCo 2 O 4 -3DNG was promising as a cost-effective non-noble metal catalyst for ORR in fuel cell technology.