Design yolk-shelled FeCo layered double hydroxide via a “one-stone-two-birds” strategy for oxygen evolution reaction

In order to meet the demands for green and sustainable energy, it is imperative to develop high-performance, cost-effective, and environmentally friendly electrocatalysts to enhance the oxygen evolution reaction (OER). In this regard, we introduce a novel reconstruction strategy, involving crystallization, growth, and etching processes, to synthesize a highly efficient electrocatalyst for the OER. A hydrothermal process was initially employed to synthesize materials of institute Lavoisier framework-88 (MIL-88) as a self-engaged precursor, which was subsequently transformed into hierarchical FeCo layered double hydroxide (LDH)@zeolitic imidazolate framework-67 (ZIF-67). Additionally, a “one-stone-two-birds” strategy was employed to create the yolk-shelled FeCo-LDH composite (denoted as YS FeCo-LDH) by etching FeCo-LDH@ZIF-67. On one hand, ZIF-67 can be gradually etched by the H+ ions generated through the hydrolysis of [Fe(C2O4)3]3−. On the other hand, simultaneously released Fe3+ and Co2+ co-precipitate with OH–/C2O42−, resulting in the formation of the FeCo-LDH shells. Benefiting from the yolk-shell structure, excellent microstructural integrity, efficient mass transport within interlinked nanocages, and abundant active sites, the YS FeCo-LDH catalyst exhibits remarkable electrocatalytic performance in the OER. This work represents a significant advancement in the development of high-efficiency yolk-shelled hollow electrocatalysts.