Preparation and enhanced CO2 adsorption capacity of UiO-66/graphene oxide composites

New composites of UiO-66 and graphene oxide (GO) were synthesized and tested as CO2 adsorbents at room temperature. The materials and the parent composite components were characterized using X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), nitrogen adsorption–desorption isotherm analysis, scanning electron microscopy (SEM), and FT-IR spectroscopy. The CO2 isotherms on the UiO-66/GO composites and the UiO-66 were measured by a static volumetric method separately. Experiments of multiple adsorption/desorption cycles were conducted to estimate reversibility of CO2 on the UiO-66/GO. The results showed that the BET surface area of the composites was higher than that of the parent UiO-66, and the adsorption capacities of CO2 on the composites were greatly higher than that on the UiO-66 sample. The composite UiO-66/GO-5 exhibited the maximum CO2 uptake of 3.37 mmol/g at 298 K and 1 bar, which increased by 48% in comparison with that of the UiO-66, and was much higher than those of the conventional activated carbons and the zeolites. The CO2 adsorption capacity was dependent on the BET surface area and the micropore volume of the composites. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of UiO-66/GO-5 was fairly stable, without noticeable degradation in the adsorption capacity of CO2 after 6 cycles. Therefore, this kind of composites has a potential application on CO2 capture technologies to mitigate global warming.