Designing of cobalt doped pyridine based covalent organic frameworks for efficient visible light driven CO2 reduction

Abstract

Covalent organic frameworks (COF) are the class of compounds that impulses the boundaries of organic/polymer chemistry and materials science to achieve the exceptional control of predesigned long-range ordered structures. The present work deals with one-pot reaction of pyridine-2,6-diamine and terephthalaldehyde in pyrex tube at slightly elevated temperature and resulted in the formation of PDT/COF. The obtained PDT/COF was then functionalized using cobalt (Co@PDT/COF). The formation of COF and metal incorporation is confirmed by Fourier transform Infrared spectroscopy (FTIR). The simulated AB staggered stacking model for both PDT/COF and Co@PDT/COF correlate well with the observed PXRD pattern than AA eclipsed stacking. The theoretical findings using materials studio software showed increase in the porosity and interlayer spacing after the addition of Co to PDT/COF. The superior photocatalytic CO2 reduction activity is observed in Co@PDT/COF compared to PDT/COF. Co@PDT/COF was able to produce 13, 24 and 45 μmol g−1h−1 of H2, CH4 and CO, respectively. The obtained experimental optical properties were correlated well with Density functional theory (DFT) studies. Based on the characterization results, mechanism of photocatalysis has been discussed. Good stability and efficiency towards photocatalytic reduction CO2 in presence of the Co@PDT/COF shows its suitability for further research on pyridine based COFs for different applications.