The Use of Density Functional Theory to Decipher the Electrochemical Activity of Metal Clathrochelates with Regard to the Hydrogen Evolution Reaction in the Homogeneous Phase

The energetic needs of a rising human population have led to the search for alternative energy sources. A promising route for the large-scale storage of renewable energy is water electrolysis, which is performed with a proton-conducting polymer electrolyte. However, only platinum group metal electrocatalysts have the adequate properties to minimize the overvoltages associated with either hydrogen or oxygen evolution reactions. Alternative materials based on transition metals are scarce, but molecular electrochemistry offers some alternatives. In particular, transition metal clathrochelates exhibit an interesting activity with regard to the hydrogen evolution reaction (HER). However, such complexes form a vast family, and there is a need to implement screening approaches to identify the most performing ones. Theoretical studies on molecular electrocatalysts are adequate for this purpose, since density functional theory (DFT) has a strong predicting capability to provide clues for the improvement of practical devices. This chapter describes the most recent theoretical methods applied to several members of the clathrochelate family. We describe the computation of their common spectroscopic and electrochemical properties. In addition, DFT analysis is used to decipher the multistep reaction mechanism of a model Co clathrochelate with regard to the hydrogen evolution reaction in the homogeneous phase