An Efficient Turing‐Type Ag₂Se‐CoSe₂ Multi‐Interfacial Oxygen‐Evolving Electrocatalyst**

Although the Turing structures, or stationary reaction-diffusion patterns, have received increasing attention in biology and chemistry, making such unusual patterns on inorganic solids is fundamentally challenging. We report a simple cation exchange approach to produce Turing-type Ag₂ Se on CoSe₂ nanobelts relied on diffusion-driven instability. The resultant Turing-type Ag₂ Se-CoSe₂ material is highly effective to catalyze the oxygen evolution reaction (OER) in alkaline electrolytes with an 84.5 % anodic energy efficiency. Electrochemical measurements show that the intrinsic OER activity correlates linearly with the length of Ag₂ Se-CoSe₂ interfaces, determining that such Turing-type interfaces are more active sites for OER. Combing X-ray absorption and computational simulations, we ascribe the excellent OER performance to the optimized adsorption energies for critical oxygen-containing intermediates at the unconventional interfaces.