Metallic mesoporous oxide single crystals delivering enhanced electrocatalytic performance†

Abstract

Porous single crystals (PSCs) are a novel class of solid-phase materials with tailored porosity. The long-range ordered lattice and interconnected pore structure in three dimensions enable them to minimize energy losses and maintain heightened catalytic activity and stability in electrochemical systems. In the process of electrocatalytic water splitting, transition metal oxides Fe₂O₃ and Co₃O₄ are regarded as highly promising catalytic materials for the oxygen evolution reaction (OER). Here, we employed a lattice reconstruction strategy to grow porous single crystals of Fe₂O₃ and Co₃O₄ through solid–solid phase transformation, utilizing FeS₂ and CoS₂ nano-octahedron single crystals as the parent crystals. PSC Fe₂O₃ and Co₃O₄ have large specific surface areas to provide enough electrocatalytic active sites while retaining the intrinsic properties of porous single crystals. Meanwhile, we quantitatively engineered Pt clusters/metal oxide interfaces on the surfaces of PSC Fe₂O₃ and Co₃O₄ to enhance the electrocatalytic performance. The PSC Pt/Co₃O₄ catalyst with lower overpotential (269 mV at 10 mA cm⁻²) exhibits optimal electrochemical performance in the OER, with no degradation observed within 25 hours. The structural consistency of these porous single crystal oxide catalysts, coupled with the construction of active interfaces, offers advantages in enhancing electrocatalytic activity and durability.