Preparation,characterization And CO₂ Adsorption Properties Of Boron Doped Mesoporous Carbon Materials

The Porous carbon nanomaterials are widely used in many fields such as CO₂ adsorption,catalysis,supercapacitors and electrode materials due to their high specific surface area,uniform pore size distribution,controllable preparation process and stable structure.In recent years,the doping technology of the nano-carbon has been developed rapidly,and the optimization of its functions can be realized by doping and modifying the nano-carbon,and the application of the nano-carbon in various research fields can be widened.A large number of experimental studies have shown that the development of boron modified mesoporous carbon materials has a great prospect.A series of boron-doped mesoporous carbon materials with mesoporous structure were prepared by hydrothermal synthesis in soft template method.The physical and chemical properties of boron-doped mesoporous carbon materials were characterized by X-ray powder diffraction?XRD?,N₂ adsorption and desorption analysis,transmission electron microscopy?TEM?,Raman spectroscopy?Raman?,Fourier transforminfraredspectroscopy?FT-IR?,X-rayphotoelectron spectroscopy?XPS?.The effects of different boron sources,boron-carbon molar ratio and template dosage on the physical and chemical properties of the material were investigated.The CO₂ adsorption and regeneration properties of the material were also tested.The main work of this paper is as follows:1.A series of boron-doped mesoporous carbon materials with different boron-to-carbon molar ratios and template dosage are prepared by using boric acid as a boron source by a hydrothermal synthesis method.The adsorption of CO₂ and the reusability of the samples were also investigated.The results show that the boron-doped mesoporous carbon materials have high specific surface area,uniform pore size,regular mesoporous and highly graphitized crystal structure.The B-doped p-type semiconductors can improve the hole transport properties of carbon,increase the graphitization degree and oxidation resistance of the materials.It was found that there were obvious differences in the adsorption of CO₂ by different materials when applied to CO₂ adsorption.In addition,the presence of boron in the carbon material significantly increases the adsorption capacity of the material to CO₂.When the boron-to-carbon ratio is 0.05?BC-0.05?and the amount of the template agent is 0.5 mmol?BC-F5?,the adsorption effect of the material is preferably excellent and the performance is excellent.The equilibrium adsorption capacity of BC-0.05 to CO₂ reaches 81.17 mg·g^-11 at 30?,ambient pressure and 50 mL CO₂ flow rate.After ten successive adsorption-desorption cycles,the adsorption capacity decreased from81.17 mg·g^-11 to 52.31 mg·g^-1.Under the same conditions,the equilibrium adsorption capacity of BC-F5 to CO₂ reached 121.34 mg·g^-1.After ten successive adsorption-desorption cycles,the adsorption capacity decreased from 121.34 mg·g^-11 to 51.77 mg·g^-1.The decrease of adsorption capacity in cyclic experiments may be due to the disappearance or weakening of vacancies on the surface of adsorbate during desorption.Secondly,it is also possible that the main reason for the material to adsorb CO₂ is physically adsorption.The results show that the boron-doped mesoporous carbon material has high CO₂ adsorption potential while reducing cost.2.A series of boron-doped mesoporous carbon materials with different boron-carbon molar ratio and template dosage were prepared by using triisopropyl borate as boron source,and the adsorption of CO₂ and the reusability of the samples were also investigated.The results show that the boron-doped mesoporous carbon materials have a series of advantages,such as high specific surface area and uniform pore size.By applying it to CO₂ adsorption,it was found that the adsorption effect of different materials on CO₂ was different.When the boron-to-carbon ratio is 0.05?BC*-0.05?and the amount of the template agent is 0.2 mmol?BC*-F2?,the adsorption effect of the material is preferably excellent and the performance is excellent.The equilibrium adsorption capacity of BC*-0.05 to CO₂ reaches 94.96 mg·g^-11 at 30?,ambient pressure and 50mL CO₂ flow rate.After ten successive adsorption-desorption cycles,the adsorption capacity decreased from 94.96 mg·g^-11 to 33.95 mg·g^-1.Under the same conditions,the equilibrium adsorption capacity of BC*-F2 to CO₂ reached 95.19 mg·g^-1.After ten successive adsorption-desorption cycles,the adsorption capacity decreased from 95.19 mg·g^-11 to 60.21mg·g^-1.The decrease of adsorption capacity in cyclic experiments may be due to the disappearance or weakening of vacancies on the surface of adsorbate during desorption.Secondly,it is also possible that the main reason for the material to adsorb CO₂ is physically adsorption.The results show that the boron-doped mesoporous carbon material has high CO₂adsorption potential.