Flux and surfactant directed facile thermal conversion synthesis of hierarchical porous MgO for efficient adsorption and catalytic growth of carbon nanotubes

Abstract

Three-dimensional (3D) hierarchical porous structures have attracted extensive attention owing to their versatile applications. Herein, 3D hierarchical porous MgO superstructures with a well faceted profile and high crystallinity were successfully obtained via a facile flux and surfactant directed decomposition of metal oxalates. As a nonionic surfactant, NP-9 served as the dispersing agent and prevented the porous MgO particles from aggregating with each other. The flux NaCl induced vapor migration through the porous structure, favoring the in situ crystallization of MgO after the phase conversion from the oxalate precursor, enhancing the toughness of the backbone and further realizing the preservation of the polyhedron-like morphology. The as-obtained hierarchical porous MgO superstructures were very efficient and effective as adsorbents for methylene blue (MB) and a catalyst support for single-walled carbon nanotube (SWCNTs) growth. The as-obtained SWCNTs afford an ultrahigh surface area of 1232 m² g⁻¹. Such superstructures could be employed as great potential candidates in dye-containing water treatment as well as heterogeneous catalysis.