Engineering MOF@LDH heterojunction with strong interfacial built-in electric field towards enhanced electrocatalytic water oxidation

Guiding the dynamic reconstruction of the oxygen evolution reaction (OER) is crucial for realizing the industrial application of hydrogen production through water electrolysis. In this study, we have intricately designed a builtin electric field (BIEF) between MIL-88B(Fe) and layered double hydroxide (LDH) with an adjusted work function difference. This design drives an asymmetric interfacial electron distribution, enhancing electron accumulation at the Fe sites within MIL-88B(Fe) and electron-deficient LDHs. Consequently, this setup promotes the surface dynamic reconstruction of LDHs into highly active oxyhydroxides, while simultaneously slowing down the rapid dissolution of Fe during OER operation. This optimization improves the adsorption/desorption of oxygen intermediates, ensuring a sustained high OER activity during long-term electrochemical operation. As expected, the optimal MIL-88B(Fe)@NiCo LDH configuration demonstrates a remarkably low overpotential of only 279 mV at 10 mA cm(-2), maintaining operational stability for 70 h. This research significantly advances our understanding of the dynamic reconstruction of MOF@LDH heterojunctions and introduces a straightforward strategy for engineering BIEF to guide this process effectively.