Metallocorroles as bifunctional electrocatalysts for water-splitting: A theoretical investigation

Abstract

Designing efficient electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is an important step of the water-splitting procedure, due to the expensive electrocatalysts and the energy loss because of overpotentials. Accordingly, in the present study and based on the newly synthesized copper-corrole complexes, several metallocorroles that can be used as electrocatalysts in water-splitting reaction were theoretically designed. The main objective of the present study is to investigate the electrocatalytic behavior of various metallocorroles toward OER at the anode as well as HER at the cathode. So, our focus will be on the corrole substrates incorporating Cr, Mn, Fe, Co, Ni, and Cu single atoms, nitrogen removal defective complexes, and Cl-functionalized corroles to explore the effect of structural modifications on the catalytic activity of metallocorroles. We found that the Ni- and Cr-corrole are encouraging catalysts for the OER and HER, respectively, outperforming the synthesized copper-based substrate and other designed metallocorroles with low overpotentials (ƞOER=0.68 V and ƞHER=0.10 V). The obtained Gibbs free energies confirm the feasibility of OER on a Ni single atom and HER on a Cr single atom of metallocorroles. The Volcano diagrams also reveal that the metallocorroles with better oxygen and hydrogen desorption correspond to the Ni- and Cr-corrole substrates, respectively. Generally, results show that our designed metallocorroles can be considered competent catalysts for water-splitting reactions.