Highly selective and efficient electroreduction of CO2 in water by quaterpyridine derivative-based molecular catalyst noncovalently tethered to carbon nanotubes

A disubstituted quaterpyridine based cobalt complex non-covalently tethered to multiwalled carbon nanotube (MWCNT) substrate, forming a hybrid catalyst, Co-qpyCOOH/CNT, catalyzed the conversion of CO2 to CO under aqueous conditions. At an optimal and uniform loading, it exhibited remarkable catalytic activity, near-exclusive selectivity, and high stability towards the formation of CO. At a mere cathodic potential of -0.65 V versus RHE (eta = 0.54 V), it achieved a high partial current density of -6.7 mA/cm(2) and a F.E.(CO) = 100%. In addition, with 20 h of stable operation, hydrogen evolution remained practically undetected. Its hybrid structure due to noncovalent immobilization on MWCNT imparted the intrinsic activity and much-needed stability in performance whereas -COOH groups may stabilize the intermediates by acting as H-bond donors, promoting catalytic activity. Tethering to a conductive solid substrate and tuning of the second sphere of coordination played an important role in its performance to achieve desired reduction product with high selectivity and activity.

Automated summary

Researchers have developed a cobalt complex catalyst based on disubstituted quaterpyridine, which is non-covalently tethered to a multiwalled carbon nanotube substrate. This hybrid catalyst, Co-qpyCOOH/CNT, demonstrates remarkable catalytic activity, near-exclusive selectivity, and high stability for the conversion of CO2 to CO under aqueous conditions. With a mere cathodic potential of -0.65 V versus RHE, it achieves a high partial current density of -6.7 mA/cm(2) and a CO selectivity of 100%.