CO2 adsorption on a water-resist HKUST-1 by incorporation of Graphene Oxide

This paper aims to improve the aqueous stability and electrochemical activity of HKUST-1 (or Cu₃(BTC)₂, BTC = benzene 1,3,5-tricarboxylate; and HKUST from Hong Kong University of Science and Technology) by the incorporation of Graphene Oxide (GO). The synthesis was carried out in two steps; first, Cu^II ions were pre-adsorbed on the surface of GO, and then the BTC organic linker was added to form the HKUST-1 structure dispersed on GO sheets. Two concentrations of copper were used in the synthesis, 3.57 and 14.27 mmol, to obtain the samples: GO@HKUST-1_low and GO@HKUST-1_high, respectively. N₂ adsorption properties of GO@HKUST-1_high suggest an increase in surface area compared to HKUST-1 up to 1082.0 m²·g⁻¹. In addition, the CO₂ capture of GO@HKUST-1_high increased from 5.34 (HKUST-1) to 6.92 mmol·g⁻¹ at 273 K and 100 kPa. This improvement is associated with the dispersion of the HKUST-1 on the GO sheets achieved through the synthesis strategy used, which also increased the surface area, H₂O adsorption capacity of the composite material, and electrochemical stability. After the H₂O adsorption tests, XRD confirmed that the material was stable under aqueous conditions, showing that the material did not undergo any structural modification.