Hierarchically Porous Carbon-Based Composites Using MOFs As The Precursor For High-Performance Capacitive Deionization

Capacitive Deionization?CDI?is a novel water treatment technology based on the principle of electrical double layer,which has attracted increasing attention due to its low energy consumption,low cost and high energy efficiency.Electrode material is a key factor in determining CDI performance.Compared with traditional carbon materials,MOF-derived porous carbon is simple to prepare,low in cost,and high in adsorption.However,MOF-derived porous carbon has problems such as poor conductivity,self-agglomeration,and low ion mobility,and there is still much room for improvement in CDI performance.Therefore,this paper mainly designs the microstructure of the electrode to accelerate the ion migration rate under the premise of ensuring high ion adsorption capacity,and achieve efficient capacitance desalination.The main research contents are as follows:Experiment 1,?1?Fe-MOF/graphene oxide hydrogel is obtained by adding pre-synthesized Fe-MOF to graphene oxide dispersion.The Fe-MOF-derived porous carbon/graphene composite material is obtained by freeze-drying,calcination,and etching.The preparation method has the advantages of simple operation,mild synthesis conditions and easy mass production,and can effectively prevent the agglomeration between the self-agglomeration of the MOF and the graphene sheets,so that the composite has high specific surface area,high electrical conductivity and rich mesoporous structure.?2?PC/rGO-20 was obtained by adjusting the ratio of Fe-MOF and graphene in the precursor,which reaching 30.3 mg g^-1 at 1.2 V in 500 mg L^-1 NaCl solution.?3?A series of MOF-derived porous carbon/graphene composites were obtained by changing the MOF species.Experiment 2,?1?ZIF-67 is calcined in a hydrogen and ethanol atmosphere,and CNTs are grown using a metal as a catalyst,and a carbon nanotube/porous carbon composites with high specific surface area and good conductivity are prepared by etching.?2?The specific surface area of a series of carbon nanotube/porous carbon composites were improved by changing the kind of doping metal.Co-Fe-CNT/PC shows the best CDI performance(37.0 mg g^-1)at 1.2 V in 500 mg L^-1 NaCl solution.In this paper,the microstructure of the electrode material based on MOF-derived porous carbon was designed by constructing a hierarchical porous structure with three-dimensional conductive network and bimetal doping while performing CNT growth,which improve CDI performance by synergistic action through the two materials,laying the foundation for the application of MOF-derived porous carbon in the field of CDI.