Introducing dual metal centers in high purity pyrrolic-N for superior oxygen reduction reaction

Transition metal- and N-codoped carbon catalysts with low cost are latent substitutes to Pt-based catalysts in oxygen reduction reaction. However, the variety of N species obtained by pyrolysis often makes the determi- nation of the active site controversial. Here, we design catalyst structures with pyrrolic-N anchored dual metal centers, while the presence of pyrrolic-N avoids the complex and variable structure of the active sites. Theory calculations demonstrate that coupling of the Cu-N4 single-atom sites is favorable to reduce the reaction energy barrier of pyrrolic-N-type Fe-N4 active site during the reaction process. Subsequently, the high-purity pyrrolic-N- type iron and copper single-atom catalyst is successfully synthesized to verify the hypothesis. The obtained FeCu-N-C catalyst achieves a half-wave potential of 0.913 V, higher than the 0.839 V of Pt/C. This route may provide new insights for regulating catalytic active sites in high purity pyrrolic-N type catalysts.

Automated summary

Transition metal- and N-codoped carbon catalysts, with pyrrolic-N anchored dual metal centers, are designed and synthesized to replace Pt-based catalysts in oxygen reduction reaction. The coupling of Cu-N4 single-atom sites reduces the reaction energy barrier of pyrrolic-N-type Fe-N4 active site, leading to the successful synthesis of high-purity pyrrolic-N-type FeCu-N-C catalyst. The obtained catalyst exhibits a higher half-wave potential compared to Pt/C, indicating its potential as an effective catalyst in the field of oxygen reduction.