Coordination effect-adjusted Co in a bimetallic zeolite imidazolate framework for efficient oxygen electrocatalysts

Abstract

Fuel cells require low-cost, efficient, durable oxygen reduction catalysts. The utilization of metal–nitrogen–carbon (M–N–C) catalysts stemming from zeolite imidazolium frameworks (ZIFs) holds immense promise in the realm of catalysis. In this paper, we report a synthesis of bimetallic zeolite imidazolium framework composite catalyst (VC-Co@NC-40) with added ligand organics prepared by high temperature pyrolysis at 800 °C. The adjustment of the metal element ratios and the addition of coordination organics were used to improve the precursor metal element distribution. Morphology and structural characterization confirmed that the Co agglomeration in the catalyst was weakened and the active sites were increased. Under alkaline conditions, electrochemical tests showed excellent oxygen reduction reaction (ORR) activity with an onset potential (E_onset) of 0.93 V and half-wave potential (E_1/2) of 0.83 V. The catalyst also showed better stability compared to commercial Pt–C. This study provides a cost-effective method for preparing ORR electrocatalysts that exhibit outstanding catalytic efficiency and exceptional stability.