Cobalt molybdenum di-selenide surface modification: A path to improved trifunctional catalysis via partial oxygenation

Abstract

Efficient, stable, and cost-effective electrocatalysts for hydrogen evolution, oxygen evolution, and oxygen reduction reactions have been in demand for decades. Recently, layered transition metals (Co, Mo, Ni, and Fe) and chalcogen compounds (S/Se/Te) gained prominence in catalysis and device studies. Density functional theory identified the covalency of Co and Mo, oxygenated bimetallic selenium bond, crystal structure distortions, and adsorption properties as crucial for enhanced electrocatalytic activity. Hybridizing the Co and Mo d-orbitals around the Fermi level of 0.463 eV improves bonding with metal surface-adsorbate intermediates validated by partial density of states. Oxygenated cobalt molybdenum selenide (O-CoMoSe2) (210) exhibited remarkable electrocatalytic properties at various active sites, with Gibbs free energy and theoretical overpotential at an active site of Co = 0.086 eV, 0.41 V, and Se = 0.50 V.