Preparation of ZIF-8/urea-modified graphene oxide composite and study on its CO2 adsorption/separation performance and stability

To overcome the challenges of particle agglomeration and insufficient stability of ZIF-8 under high-temperature and high-humidity conditions during CO 2 capture, this study developed a ZIF-8/urea-modified graphene oxide (GO) composite and systematically investigated its microstructure, CO 2 adsorption and separation performance, and stability. The results demonstrate that urea-modified GO is uniformly dispersed within the ZIF-8 in a highly exfoliated state and enables the formation of a microporous-mesoporous hierarchical pore structure through synergistic interaction. At 273 K and 101 kPa, the composite achieves a CO 2 adsorption capacity of 2.36 mmol/g and a CO 2 /N 2 selectivity of 24.6, showing 40.5% and 62.9% enhancements compared with pristine ZIF-8. Due to the synergistic effect between urea-modified GO and ZIF-8, the composite exhibits notable improvements in thermal, adsorption-desorption cycling, and moisture stability. This work provides both experimental data and theoretical insights for the rational design of high-performance adsorbents tailored to practical flue gas CO 2 capture applications.