Boosting Efficient and Sustainable Alkaline Water Oxidation on a W‐CoOOH‐TT Pair‐Sites Catalyst Synthesized via Topochemical Transformation

Abstract The development of facile methods for constructing highly active, cost‐effective catalysts that meet ampere‐level current density and durability requirements for an oxygen evolution reaction is crucial. Herein, a general topochemical transformation strategy is posited: M‐Co 9 S 8 single‐atom catalysts (SACs) are directly converted into M‐CoOOH‐TT (M = W, Mo, Mn, V) pair‐sites catalysts under the role of incorporating of atomically dispersed high‐valence metals modulators through potential cycling. Furthermore, in situ X‐ray absorption fine structure spectroscopy is used to track the dynamic topochemical transformation process at the atomic level. The W‐Co 9 S 8 breaks through the low overpotential of 160 mV at 10 mA cm −2 . A series of pair‐site catalysts exhibit a large current density of approaching 1760 mA cm −2 at 1.68 V vs reversible hydrogen electrode (RHE) in alkaline water oxidation and achieve a ≈240‐fold enhancement in the normalized intrinsic activity compare to that reported CoOOH, and sustainable stability of 1000 h. Moreover, the O─O bond formation is confirmed via a two‐site mechanism, supported by in situ synchrotron radiation infrared and density functional theory (DFT) simulations, which breaks the limit of adsorption‐energy scaling relationship on conventional single‐site.