2-Methylimidazole-tuned “4-Self” strategy based on benzimidazole-5-carboxylate for boosting oxygen reduction electrocatalysis

Abstract

Rational design highly active transition metal or transition metal oxides/nanocarbon hybrids is one of the feasible way to deliver a cooperative oxygen reduction (ORR) with a synergistic effect of the hybrid interface. Herein, based on benzimidazole-5-carboxylate (BIMC), CoO/Co-N-C nanocomposites are fabricated via 2-methylimidazole (2-MeIm)-tuned “4-Self” strategy, namely, self-templating, self-adapting, self-assembly and self-catalysis. As a base competitive ligand with N and C sources, 2-MeIm modulates the dispersion of BIMC in methanol to generate collodial-like BIMC tiny particles, the coordination ability of BIMC to Co(II), the composition and morphology of the self-assembled precursor (Co-BM), and as well as the conductivity of the resultant electrocatalyst. Impressing, carbonization of Co-BM at 800 °C under N2 atmosphere endows the pyrolysis product (Co-BM-800) with the well-dispersed Co/CoO riveted on nitrogen-doped carbon, as well as the enhanced ORR performance in terms of positive onset-potential (0.890 V vs. RHE), large diffusion limiting current density (5.21 mA cm−2), and high stability.