Double-Shelled NiCo-LDH@MSiO3(M = Ni, Cu, Mn) Hollow Polyhedral Cages for Efficient Adsorption Toward Anionic Organic Pollutant

Abstract

Hierarchical hollow nano-/micro-architectures with complex multishelled structures are highly desirable for achievement of various functionalities. However, it is still a great challenge to integrate multinary compositions into a nonspherical hollow structure with complex multishells. Herein, we developed an effective strategy to construct hierarchical double-shelled NiCo-layered double hydroxides@MSiO3 (NiCo-LDH@MSiO3, M = Ni, Cu, Mn) hollow polyhedral nanocages with inner NiCo-LDH and outer MSiO3 layers. Our design principle involved a one-pot synthesis of Co-based zeolitic imidazolate framework-67@SiO2 (ZIF-67@SiO[Formula: see text] core@shell polyhedrons and a subsequent two-step in situ chemical conversion reaction process. Benefiting from the structural merits including high specific surface area, abundant mass diffusion pathways, and the unique hierarchical hollow structures, the double-shelled NiCo-LDH@MSiO3 hollow polyhedral cages exhibited significant adsorption capacity of Congo red. Especially, the maximum adsorption capacity of the double-shelled NiCo-LDH@NiSiO3 hollow polyhedral cages could reach up to 510.6[Formula: see text]mg/g, implying a high efficiency for the removal of Congo red from aqueous solution and a potential application in water treatment.