A Dual‐Function Catalyst for Efficient Electrocatalytic Water Splitting: Harnessing the Synergy of Cobalt‐Phosphorus‐Nitrogen PN³P

Abstract A robust cobalt‐based PN³P‐pincer molecular complex is introduced that serves as an efficient bifunctional electrocatalyst for electrochemical water splitting. This water‐soluble, electron‐deficient cobalt PN³P‐pincer complex demonstrates impressive catalytic activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), utilizing metal‐ligand cooperation to optimize the overpotential for water splitting. Importantly, the (pseudo)dearomatized species, with a nucleus‐independent chemical shift (NICS) value of −14.6, show excellent OER activity, while the aromatized species achieve superior HER performance at an exceptionally low overall overpotential (≈0.46 V), outperforming other reported cobalt‐based molecular catalysts. Stability assessments confirm the catalyst's durability during prolonged electrolysis, exhibiting minimal decomposition and high Faradaic efficiency. Insights from density functional theory (DFT) calculations demonstrate a lower‐energy pathway for the (pseudo)dearomatized complex in the OER, consistent with experimental results. This research emphasizes the promise of aromaticity‐controlled molecular design for enhancing electrocatalytic water splitting, contributing to renewable energy applications and sustainable hydrogen production.