Ultrafast room temperature synthesis of GrO@HKUST-1 composites with high CO2 adsorption capacity and CO2/N2 adsorption selectivity

Abstract

An ultrafast synthesis method is developed for the preparation of composites of graphite oxide and HKUST-1, GrO@HKUST-1. Fast synthesis of GrO@HKUST-1 composites can be quickly achieved at room temperature within 1min. The synthesized composites were characterized by XRD, SEM, N2 adsorption, FTIR and TGA. The isotherms of CO2 and N2 on the as-synthesized materials were measured and the isosteric heats of CO2 adsorption were estimated. The CO2/N2 adsorption selectivities were predicted by means of ideal adsorbed solution theory (IAST). Results show that the GrO@HKUST-1 composites have higher BET surface area and pore volume than the parent HKUST-1. The CO2 adsorption capacity of 2GrO@HKUST-1 (2% of GrO) is up to 9.02mmol/g at 1bar and 273K, giving an increase of 32% in comparison of the parent HKUST-1. The isosteric heat of CO2 adsorption on 2GrO@HKUST-1 is slightly higher than that of HKUST-1, suggesting the stronger interaction between CO2 molecules and 2GrO@HKUST-1. The CO2/N2 adsorption selectivity of 2GrO@HKUST-1 is significantly enhanced over pristine HKUST-1. At 1bar, the CO2/N2 adsorption selectivity of 2GrO@HKUST-1 is up to 186, while that of parent HKUST-1 is only 103. This rapid room temperature synthesis route is promising for new MOF-based composites.