Nitrogen-Doped Carbon Nanosheets Supported Co for Efficient and Stable Electrocatalytic Oxygen Reduction

Designing highly efficient non-noble metal electrocatalysts to replace state-of-the-art noble metal electrocatalysts such as Pt is crucial for large-scale application of hydrogen fuel cells. In this paper, we proposed a facile synthetic strategy using metal–organic framework material as a template to achieve evenly distributed Co nanoparticles (Co NPs) on the N-doped carbon nanosheets with high specific surface area and electrocatalytic activity toward the oxygen reduction reaction (ORR). The presence of pyrrolic N modulated the electronic structure of Co to promote the ORR catalytic activity while hindering the Co NPs from aggregation. The results show that the carbon nanosheet-supported Co NPs have the best ORR electrocatalytic activity at an optimal annealing temperature (900 °C). The electrocatalyst exhibited an onset potential (Eonset) of 0.96 V vs. RHE and a half-wave potential (E1/2) of 0.89 V vs. RHE, which outperformed the commercial 20% Pt/C. At the same time, it also showed better oxygen evolution reduction and zinc–air battery (ZAB) performance than commercial RuO2 and 20% Pt/C. Therefore, this work can provide guidance for the design and synthesis of multifunctional non-noble metal electrocatalysts for future ZAB applications.