Harnessingthe Cobalt-Catalyzed Hydrogen EvolutionReaction through a Data-Driven Approach

The design of cobalt complexes for the hydrogen evolution reaction (HER) has garnered significant attention over the past few decades. To address the limitations of the traditional trial-and-error method, we introduced the strategy of a simplified mechanism-based approach with data-driven practice (SMADP) in this study. Our results indicate that the polypyridyl cobalt complexes of the DPA-Bpy family (DPA-Bpy = <i>N</i>,<i>N</i>-bis(2-pyridinylmethyl)-2,2′-bipyridine-6-methanamine) generally follow the electron transfer (E)–chemical proton transfer (C)–electron transfer (E)–chemical proton transfer (C) pathway in HER. However, the involvement of proton-coupled electron transfer (PCET) in the formation of the [Co^II(L)–H]⁺ intermediate has been observed in the PY₅Me₂ family (PY₅Me₂ = 2,6-bis(1,1-di(pyridin-2-yl)ethyl)pyridine). Furthermore, the hydricity of the [Co^II(L)–H]⁺ intermediate (Δ<i>G</i>_H^_–) and the Co^III–H/Co^II–H reduction potential (<i>E</i>_Red^°) are found to be the active descriptors in the cobalt-catalyzed HER. Excellent two-parameter regression models (Δ<i>G</i>_H^_– and <i>E</i>_Red^°) for the formation of the H₂ molecule have been obtained (<i>R</i>² = 0.9429 for the DPA-Bpy family and <i>R</i>² = 0.9854 for the PY₅Me₂ family). Our results demonstrate that the SMADP strategy is a groundbreaking method for delineating active descriptors in the cobalt-catalyzed HER. This data-driven approach could also accelerate the design of novel polypyridyl cobalt complexes for enhanced HER.