Photocatalytic CO2 Reduction Using Homogeneous Carbon Dots with a Molecular Cobalt Catalyst

Identifier:  imarina:9423949

Handle: https://hdl.handle.net/20.500.11797/imarina9423949

Authors:  Kim, Dongseok; Bhattacharjee, Subhajit; Lam, Erwin; Casadevall, Carla; Rodriguez-Jimenez, Santiago; Reisner, Erwin

Abstract:
A simple and precious-metal free photosystem for the reduction of aqueous CO2 to syngas (CO and H-2) is reported consisting of carbon dots (CDs) as the sole light harvester together with a molecular cobalt bis(terpyridine) CO2 reduction co-catalyst. This homogeneous photocatalytic system operates in the presence of a sacrificial electron donor (triethanolamine) in DMSO/H2O solution at ambient temperature. The photocatalytic system exhibits an activity of 7.7 +/- 0.2 mmol(syngas) g(CDs)(-1) (3.6 +/- 0.2 mmol(CO) g(CDs)(-1) and 4.1 +/- 0.1 mmol(H2) g(CDs)(-1)) after 24 hours of full solar spectrum irradiation (AM 1.5G). Spectroscopic and electrochemical characterization supports that this photocatalytic performance is attributed to a favorable association between CDs and the molecular cobalt catalyst, which results in improved interfacial photoelectron transfer and catalytic mechanism. This work provides a scalable and inexpensive platform for the development of CO2 photoreduction systems using CDs.