Halloysite nanotubes loaded with HKUST-1 for CO2 adsorption

Abstract

Halloysite nanotubes (HNTs) loaded with HKUST-1 (HKUST-1@HNT) were synthesized and characterized. HKUST-1, a metal-organic framework, was encapsulated in HNTs that served as nanocarriers of precursor so-lutions allowing for the formation of nanosized HKUST-1 crystals. In this study, HKUST-1@HNT composites were prepared using vacuum loading and solvothermal reactions. HNTs were modified by etching the inner layers and amine functionalizing the outer surface. Electron microscopy, X-ray diffraction, and thermogravimetric analysis were used to characterize the concentration of HKUST-1 in HNTs, and Brunauer-Emmett-Teller (BET) methods were employed to investigate N-2 and CO2 gas adsorption performances. Results showed that the loading capacity of HKUST-1 crystals increased with the magnitude of etching treatment. The crystalline structure was established in conjunction with the tubular structure of the HNTs. The gas adsorption capacity was enhanced in HKUST-1@HNT and increased with the loading capacity of HKUST-1. Furthermore, when amine-functionalized HNTs were used, the composites exhibited effective CO2 adsorption performance. Results showed that the synthesis of HKUST-1 and HNTs hybrid materials is a promising strategy for the development of novel adsorbing materials.