Preparation Of New Carbon Materials And Carbon Composites For FGD And Supercapacitor

The continuous shortage of fossil energy consumption has led to the increasingly serious ecological environment pollution and energy shortage.In recent years,global SO₂ emissions have become increasingly serious,and the shortage of new green energy storage/supply devices will further aggravate this pollution.Therefore,it is very important for us to use green and renewable materials to further improve the performance of energy storage/energy supply device and to solve the environmental pollution problem by flue gas desulfurization.Carbon materials and their composites are widely used in flue gas desulfurization and supercapacitors due to their high specific surface area,abundant pore structure,high stability and good conductivity measurement.In this paper,different carbon precursors and carbonization methods were used to prepare carbon materials and carbon composites for different application environments.In this work,we report a facile one-step method for the synthesis of biomass-derived porous carbons with high specific surface areas(1195-1449 m² g^-1),mesoporous pore size?4-7 nm?and good SO₂ adsorption properties.Our carbon adsorbents exhibited an outstanding SO₂ adsorption capacity of 10.7 mmol g^-1 at 298K,which is more than twice the SO₂ capacity of benchmark carbon material cs1000a(approximately 5.0 mmol g^-1)and commercial carbon CKM-3(5.1 mmol g^-1).The new carbon adsorbents also showed an unprecedented SO₂/CO₂,SO₂/CH₄ and SO₂/N₂separation selectivities of 32,127 and 2349,respectively,which are comparable and even better than the best MOF adsorbents for SO₂ removal.Dynamic breakthrough experiments with an actual flue gas composition confirmed the feasibility of efficient removal of SO₂ from flue gas in an adsorbent column.In addition,density function theory simulation further illustrates that-NO_x and-OH groups in the carbon frameworks provide strong interactions with SO₂ molecules.The electrochemical test of the three-electrode system shows that the electrochemical stability of the material is good,and the electrolyte resistance and ion-transfer diffusion resistance are both low.The carbon adsorbents synthesized in this work are promising for flue gas desulfurization,natural gas purification and supercapacitor applications.In addition,hollow carbon nanotube?MC?was formed by heat treatment of melamine cotton.The nickel/cobalt layered double hydroxide?NiCo LDH?was further grown on the MC via a facile hydrothermal method to fabricate the NiCo LDH@MC3D composites.The MC substrate could efficiently disperse the NiCo LDH and prevent the aggregation.Meanwhile,the hollow structure also provides a convenient ions transport channel.Moreover,the obtained NiCo LDH@MC 3D composites exhibited a high specific capacitance,excellent rate retentions,and long durability as supercapacitor electrodes.The results show that the specific capacitance of NiCo LDH@MC is 1326.8 F g^-1 at a current density of 0.5 A g^-1,and the energy density is31.53 Wh kg^-1 at the power density of 2500 W kg^-1.After 1000 cycles at the current density of 5 A g-1,the capacitance retention rate remains 83.8%,and the specific capacitance is 880.1 F g^-1.Therefore,the prepared NiCo LDH@MC could be used as an advanced supercapacitor electrodes.Finally,in this paper,H₂O₂/HAC solution was used to peel the loofah at high temperature and then activated by NaHCO₃ to successfully prepare carbon nanosheets with uniform pore size distribution and pore size of 1.2 nm.The contact area between electrode and electrolyte is increased,and the electrochemical properties are improved.Through the three electrode electrochemical tests show that SG-H under the current density of 0.5 A g^-1,electric capacity of 288.1 F g^-1,the energy density is 26Wh kg^-1 at the power density of 2500 W kg^-1.After 1000 cycles at the current density of 5 A g-1,the capacitance retention rate remains 83.4%,and the electric capacity is240.1 g F^-1.It shows that this material has good reversibility and potential as the electrode of supercapacitor.By high temperature stripping,R_f fell to 2.1?,showed that for the electrochemical reaction process of ion diffusion provides a convenient channel,effectively reduces the material resistance.The carbon nanosheet prepared in this experiment is a very promising supercapacitor material.