Study On ZIF-8@GO Composites Synthesis,Functional Modification And Their CO₂ Adsorption Properties

The greenhouse effect caused by CO₂ emission from fossil fuel combustion was becoming more and more serious,so it was urgent to develop new adsorbents with CO₂adsorption performance.Among many adsorbents,metal-organic frameworks(MOFs)had potential application value in the field of CO₂adsorption due to their large specific surface area,controllable pore structure,design ability and strong interaction with gas molecules.However,when MOFs materials were used at high temperature,the framework of MOFs materials would twist,deform and collapse due to the rise of temperature,thus losing the CO₂adsorption performance.To further improve the thermal stability and CO₂adsorption performance of MOFs,ZIF-8 material with better stability was selected to study on ZIF-8 and graphene oxide(Graphene Oxide,GO)composite and functionalization modification.Three kinds of composite ZIF-8@GO?ZIF-8@GO-COOH and Cu-ZIF-8@GO-COOH were prepared to reveal the effect of carboxyl functionalization and doped copper ions on the thermal stability and CO₂adsorption properties of ZIF-8@GO composites.The microstructure,thermal stability and CO₂adsorption properties of three functionalized ZIF-8 composites were studied by XRD?FTIR?SEM?TG?BET?XPS and other characterization methods and main conclusions were as follows:(1)The study on the influence of ZIF-8@GO composites material on the CO₂adsorption performance showed the introduction of GO was not affect the crystal structure of ZIF-8 and increased the thermal decomposition temperature and CO₂adsorption capacity of ZIF-8.When the addition amount of GO was8wt%,the ZIF-8@GO composite showed the thermal decomposition temperature of the composite was 480?,the BET specific surface area and Langmuir specific surface area were 1037.18m²/g and 1115.90m²/g respectively and the CO₂adsorption capacity was 34.35cm³/g which was 32.3%higher than that of ZIF-8.(2)The study on the influence of ZIF-8@GO-COOH composites material on the CO₂adsorption performance showed the introduction of GO-COOH was not affect the crystal structure of ZIF-8 and increased the thermal decomposition temperature and CO₂adsorption capacity of ZIF-8@GO.When the addition amount of GO-COOH was 8wt%,ZIF-8@GO-COOH composite showed the thermal decomposition temperature of composite was 560?,BET specific surface area and Langmuir specific surface area were 1319.80m²/g and1381.85m²/g respectively and the CO₂ adsorption capacity was 37.50cm³/g which was 44.4%higher than that of ZIF-8.(3)Doping copper ion in ZIF-8@GO-COOH,the crystal structure of ZIF-8was not affected by the introduction of copper ions,which improved on the thermal decomposition temperature and CO₂adsorption capacity of ZIF-8@GO.When the addition amount of copper ion was 10wt%,Cu-ZIF-8@GO-COOH composite showed the thermal decomposition temperature of the composite was590?,BET specific surface area and Langmuir specific surface area were1387.67m²/g and 1466.07m²/g respectively and the CO₂adsorption capacity was39.94cm³/g which was 53.8% higher than that of ZIF-8.