Lewis-basic PO43- induced interfacial water dissociation on CoWO4 for enhanced neutral oxygen evolution reaction.

In neutral water electrolysis, the intrinsically low OH- concentration compels the oxygen evolution reaction (OER) to proceed via an additional water dissociation step, leading to sluggish kinetics and high overpotential, which poses a challenge for efficient catalyst design. Introducing Lewis base sites on the catalyst surface can act as proton acceptors, accelerating HOH bond cleavage and thereby promoting the generation and accumulation of *OH. Herein, we incorporated the Lewis base PO43- into CoWO4 to construct a self-supporting PO43--CoWO4 electrode. The incorporated PO43- engages in electronic interactions with Co/W active sites, modulating the local electronic structure. Electrochemical tests demonstrate that PO43--CoWO4 exhibits outstanding OER performance in 1 M phosphate buffer solution (PBS), achieving an overpotential of only 330 mV at 10 mA cm-2 and stable operation over 250 h. Mechanistic studies reveal that PO43- optimizes the interfacial water on CoWO4, increases the fraction of free water, facilitates water dissociation, and enhances the surface *OH coverage. Moreover, it effectively suppresses the leaching of active Co/W species during OER, thereby improving the structural stability of the catalyst. This interfacial regulation by PO43- synergistically boosts the activity and stability of neutral OER, providing new insights for designing highly efficient neutral water electrolysis catalysts.