Computational electrochemistry of water oxidation on metal‐doped and metal‐supported defective h‐BN

by D. Perilli, D. Selli, H. Liu and C. Di Valentin

ChemSusChem, 2019, 12, pp 1995-2007 View at Publisher

DOI: https://doi.org/10.1002/cssc.201802499
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Metal‐doped and metal‐supported bidimensional materials are attracting a lot of interest as potentially active electrocatalysts for reduction and oxidation processes. In a previous work, we have shown that when a non‐regular 2D h‐BN layer is grown on a Cu (111) surface, metal adatoms spontaneously pop up from the bulk to fill the atomic holes in the structure and become available for surface catalysis. Here, we investigate and compare, by means of computational electrochemistry, the performance of Cu‐doped and Cu‐supported pristine and defective h‐BN systems for the electrocatalysis of the water oxidation reaction. For the various model systems, we identify the intermediate species of this multistep oxidation process and compute the free energy variations for each step of reaction, even for those steps that do not involve an electron or a proton transfer. Both associative and O2 direct evolution mechanisms are considered. On this thermodynamic basis, we determine the potential determining step (PDS), the thermodynamic determining step (TDS) and consequently the theoretical overpotential (η) for comparison with experiments. Small Cu clusters (tetramers) trapped in the h‐BN defective lattice on a Cu(111) support are found to be very active for water oxidation reaction since such systems are characterized by a low overpotential and by a small energy cost for O2 release from the catalyst, which is often observed to be a major limit for other potential electrocatalyst material.