Hybridizing of metal-organic framework in selectively modified clay nanotube

Abstract

In this study, the surface of halloysite nanotubes was modified selectively and hybrid materials were synthesized with the modified nanotubes and HKUST-1. Halloysite has different electric charges inside and outside the tube, so it can be selectively modified as needed, thereby inducing differentiated characteristics. Herein, halloysite served as a nanocarrier for loading the precursor solution of HKUST-1 inside the lumen, and therefore nano-sized HKUST-1 crystals were successfully synthesized in the limited space. Moreover, the halloysite, whose surface was selectively modified, exhibited unique properties to the surface of the synthetic composite material. Through the etching process using sulfuric acid, the internal space of the halloysite was expanded, which enabled the precursor solution to be effectively loaded into the tube. On the other hand, the introduction of amine groups using (3-Aminopropyl)triethoxysilane promoted chemical bonding between the outside of the tube and CO2 gas, thereby increasing the gas adsorption capacity. This study suggested the possibility of synthesizing various composite materials using nanotubes and showed synergistic effects through the synthesis of composite materials. Also, the results of this study are expected to contribute to the development of adsorbents for gas adsorption in the future and to expand the application of nanotubes.