Issue 42, 2023

Revealing insights into the axial coordination effect of M–N4 catalysts on electrocatalytic activity towards the oxygen reduction reaction

Abstract

Axial coordination is a powerful strategy to effectively regulate the activity of M–N4 catalysts. However, the underlying mechanism is still not clear. Here, we explore the influence of axial coordination on the activity of Fe/Co/Ni-tetraphenylporphyrin covalent organic frameworks (Fe/Co/Ni-TPP COFs) towards the oxygen reduction reaction (ORR) using the DFT method. It is found that the widely used descriptors (e.g., d-band centers) are not applicable to explain the axial coordination effect on metal reactivity. The reason is that the hybridization of the dz2 orbital of metal centers and pz orbital of axial coordination atoms leads to the formation of new active orbitals, where the effect of the pz orbital should be considered in the design of the activity descriptor. Based on this, an activity descriptor using the total number of electrons in dz2 and pz orbitals is proposed. The results show that the reactivity of the metal center is enhanced by axial coordination if N(dz2) + N(pz) > 2, while it is reduced if N(dz2) + N(pz) ≤ 2. The application of the descriptor is further extended to explain the activity change of Fe/Co/Ni-TPP COFs by different types of axially coordinated atoms. This work provides new insights into the regulation mechanism of the axial coordination effect on metal reactivity.

Graphical abstract: Revealing insights into the axial coordination effect of M–N4 catalysts on electrocatalytic activity towards the oxygen reduction reaction

Supplementary files

Article information

Article type
Paper
Submitted
24 Jun 2023
Accepted
10 Oct 2023
First published
11 Oct 2023

J. Mater. Chem. A, 2023,11, 23080-23086

Revealing insights into the axial coordination effect of M–N4 catalysts on electrocatalytic activity towards the oxygen reduction reaction

Y. Ni, W. Xie and J. Chen, J. Mater. Chem. A, 2023, 11, 23080 DOI: 10.1039/D3TA03701K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements