DFT-metadynamics insights on the origin of the oxygen evolution kinetics at the (100)-WSe2 surface

Water oxidation or oxygen evolution reaction (OER) in electrochemical cells is considered to be a major bottleneck in the way of hydrogen production by electro-synthesis, mainly due to a sluggish kinetics that characterizes the OER steps. Layered transition metal dichalcogenides, such as WSe₂, are emerging as promising non-precious electrocatalysts for water splitting due to their excellent activity and stability. This paper aims to shed light on the (100) WSe₂-aqueous interface in catalyzing the slow kinetics of the OER in the context of water splitting electro-catalysis. We employ state-of-the-art DFT-metadynamics to explore reaction mechanisms, activation free energies, and catalytic sites. This study reveals an energetically preferred water-assisted OER mechanism, where proton transfer is facilitated by the surrounding aqueous environment. Our findings not only provide insights into the OER process but also offer a design strategy for optimizing WSe₂-based catalysts and a modeling protocol for future DFT-based OER investigations.