CoN4 active sites coupled with low-loading Pt as advanced oxygen electrocatalyst for proton exchange membrane fuel cells

Abstract

Proton exchange membrane fuel cells (PEMFCs) are regarded as a cornerstone of next-generation energy conversion technologies due to zero emission and high energy efficiency. However, the high cost and scarcity of conventional Pt-based electrocatalysts hinder its commercialization. Herein, we successfully developed a platinum and cobalt bimetallic covalent organic polymer (Pt-CoNC) electrocatalyst with low Pt loading (0.96 wt%) for the oxygen reduction reaction (ORR) by integrating Pt sites with carbon materials featuring Co-N4 active centers. This unique structural design not only effectively mitigates the high cost associated with Pt-based catalysts but also notably boosts the activity and stability of non-precious metal catalysts. The results verified that the half-wave potential of Pt-CoNC in the acidic ORR was increased by 105 mV as compared with pure cobalt phthalocyanine-based covalent organic polymer (COP-Co). Furthermore, the as-assembled PEMFC device achieved a peak power density of 1.14 W cm−2 under an H2-O2 atmosphere, which is comparable to commercialized 20% Pt/C catalysts.