Work

Investigating the Intrinsic Activity, Nature, and Deactivation Pathway of a Carbon-Nanotube-Confined Molecular Co Catalyst for CO 2 Reduction

Year: 2026

Type: article

Abstract: Cathodes functionalised using molecular catalysts represent a promising approach for the efficient conversion of CO₂ into valuable products, with the potential to meet the performance metrics relevant to industrial applications. However, assessing the intrinsic activity of the metal centre while maintaining stability of the catalysts molecular scaffold during electrolysis still remains a challenge. This work focuses on the in-depth characterisation of a tetraaza-macrocyclic cobalt complex-based molecular cathode, from gaining a more accurate description of the catalysts performance metrics to the investigation of its probable deactivation pathway during electrocatalytic CO2 reduction (CO2RR). Importantly, our findings confirm that lowering the surface concentration of the catalysts allows to reach a catalytic regime where the activity is not anymore limited by mass transport within the porous multiwalled carbon nanotubes film but by the intrinsic activity of the immobilised catalyst, therefore allowing to determine its TOFmax value of 4.9 s-1. We propose that at least two populations of catalysts are present at the electrode surface, with variable contribution to the electrocatalytic process. Post operando studies provide key insights on the deactivation process of the immobilised catalyst via hydrogenation of both imine functions followed by demetallation.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c22597