Engineered atomically dispersed cobalt sites in one dimensional pyridine-based covalent organic frameworks for enhanced photocatalytic CO2 reduction

Abstract

Metal-coordinated covalent organic frameworks (COFs) have attracted significant attention for photocatalytic CO 2 reduction, but the precise role of coordination microenvironments engineering and topological structure in modulating charge transfer dynamics remains unclear. Herein, we synthesized two novel one-dimensional COF architectures incorporating distinct chelating motifs-phenanthroline and imine-pyridine units. By anchoring cobalt ions, two atomically dispersed cobalt-coordinated COFs (Co-Phen-COF and Co-Py-COF) were successfully constructed for efficient photocatalytic CO 2 reduction. Notably, Co-Py-COF exhibited superior photoelectric properties and a higher CO generation rate compared to the pristine COF and Co-Phen-COF. The experimental and theoretical analyses revealed that the synergistic interaction between single-atom Co 2+ sites and one-dimensional Py-COF configuration enhanced CO 2 adsorption, promoted charge migration and carrier separation, and lowered the formation energy barrier of the rate-determining intermediate. Mechanistic studies demonstrated that the localized charges at the interface of Co sites and Py-COF were redistributed and more photogenerated electrons were accumulated around the single-atom Co 2+ sites in Co-Py-COF, promoting CO 2 activation and improving CO 2 reduction efficiency. This study offers a promising strategy for optimizing photocatalytic CO 2 -to-CO conversion by fine-tuning metal-chelating microenvironments within COF frameworks.