Hydrogen Evolution Reaction on Cobalt-Nickel Phosphide Clusters: A Descriptor-Based DFT Study

The hydrogen evolution reaction (HER) involves reduction of protons at catalytically active sites, with molecular hydrogen formation proceeding via Tafel or Heyrovsky mechanism.  In this work, we assess the potential of cobalt nickel phosphide cluster as electrocatalysts using Density Functional Theory (DFT) and identify the structural and electronic factors governing their HER activity.

The adsorption energies of hydrogen atoms at representative active sites to evaluate catalytic performance and the Gibbs free energy () of adsorption is used as the principal activity descriptor. The correlation between and the local atomic and charge environment is examined using multiple structural fingerprints, including the generalized coordination number (GCN), atom-centered symmetry functions (ACSFs), and smooth overlap atomic orbitals (SOAP) representation [1-3].

For the electronic fingerprints, both the first and second moments of the d-band density of states are calculated to capture the center and width of the metal d-band as descriptors of reactivity. Insights gained from this study are expected to guide descriptor-driven screening and rational design of transition metal phosphide-based electrocatalysts for hydrogen evolution and related electrochemical processes.

[1]   Federico Calle-Vallejo et al. Science 350, 185 (2015)

[2]   J. Behler, J. Chem. Phys. 134, 074106 (2011)

[3]   A.P. Bartók, R. Kondor, G. Csányi, Phys. Rev. B 87 (2013) 184115