Fabrication of layered double hydroxide microcapsules mediated by cerium doping in metal-organic frameworks for boosting water splitting

Assembly of micro-/nanocapsules holds great potential for catalysis, storage, and drug delivery due to their modifiable shell, high exposed surface area, and large accommodation space. Here, an ingenious one-step reaction strategy is presented to fabricate layered double hydroxide (LDH) microcapsules, which benefit from the oxyphilic and synergistic coordination of Ce species to stabilize the initial morphology of metal-organic frameworks (MOFs). Taking advantage of this unique superstructure, the as-prepared Ni-Fe-Ce-LDH microcapsules demonstrate excellent oxygen evolution reaction (OER) activity with an overpotential of 242 mV at 10 mA cm(-2)and long-term durability of at least 24 h. Density functional theory (DFT) results further confirm the electronic modulation induced by the Ce doping for both subtle 3D LDH architectures and superior OER performances. This work not only provides insight into the rare-earth (RE) doping mediated crystal growth and transformation process of MOFs but also represents a facile way to fabricate the desired microcapsule superstructure by virtue of the Lewis acid property and synergistic coordination of RE-ions.