Spatiotemporal Control of MOF Reconstruction Unlocks Efficient Oxygen Evolution.

Abstract

Understanding the dynamical reconstruction mechanisms of the active phase in metal-organic frameworks (MOFs) during the course of oxygen evolution reaction (OER) is central to the development of efficient and durable OER catalysts, but remains elusive till present. Herein, a spatiotemporally decoupled reconstruction strategy is pioneered to engineer a dual-metal-node MOF ([Fe₃O(hbdc)₃][Ni₂(trz)₃]) catalyst (hbdc: 2-hydroxyterephthalic acid, trz: 1,2,4-triazole), in which orbitally coupled pore-microenvironments drive time-phased kinetic reconstruction of the spatially separated Fe/Ni metal nodes, creating a foundational platform to lay bare the mechanisms governing the reconstruction processes and the cross-scale kinetic. Furthermore, a multimodal operando diagnostic platform is developed that integrates in situ X-ray absorption spectroscopy (XAS), in situ Raman spectroscopy, and real-time reaction kinetics tracing, to decipher the MOF atomic-to-mesoscale reconstruction kinetics from the Fe-centered active phase to the NiFe-centered more active phase. Crucially, the purpose-partitioned pore architecture synergizes the interplay between the Fe─Ni nodes, while the self-adaptive defects, bond relaxation, and structural regeneration collectively modulate the kinetic behavior, leading to the pronounced OER activity enhancement. This work establishes a structural dynamics tracking methodology that can integrate multi-scale characterization techniques and provide deep insights into the reconstruction mechanisms, thus filling the critical gap in understanding structure-activity relationships under operando conditions.