A DFT-based determination of the mechanism of electrochemical reduction of CO₂ to CO by a cobalt-Schiff base catalyst

Authors

Meliton R. Chiong III; Francis N. C. Paraan

Source

9th Electronic Structure and Processes at Molecular-Based Interfaces Workshop, National University of Singapore, Singapore, P024 (2017).

Abstract

We perform density functional theory (DFT) based calculations to investigate the reduction of carbon dioxide CO2 to carbon monixide CO using a cobalt-Schiff base catalyst, Co(salen). DFT calculated formation energies and reduction potentials showed that CO2 is reduced to CO via a [Co(salen)-COOH] intermediate. The first step of the mechanism involves the reduction of electrically neutral [Co(salen)] to [Co(salen)]- anion, followed by an electrophilic addition of CO2. Furthermore, the sigma bond formed between cobalt metal center and CO2 involves a back-donation and partial charge transfer from cobalt to carbon. [Co(salen)-COOH] is further reduced to [Co(salen)-CO] and CO is released from the catalyst along with water H2O.