Preparation Of MXene-based Catalysts And Research On Performance Of Plasma Synergistic Catalytic Denitrification

The exhaust gas emitted from human production and life has caused a lot of irreversible harm to the environment,and nitrogen oxides（NO_X）,as the most difficult part of exhaust gas treatment,has seriously affected people’s daily life.As a new type of gas pollutant treatment technology,plasma out-of-stock technology improves the technical defects of traditional out-of-stock processes such as large energy consumption and high cost,and avoids the reducing agent required in SCR（selective catalytic reduction）,and does not produce secondary pollution,which is one of the most promising and effective technologies in the treatment of air pollution.This topic selects two-dimensional transition metal carbide（MXene）as the main material to study the performance of plasma catalytic denitrification.Due to its excellent physical and chemical properties,MXene material can not only maintain a good reaction state in the plasma electric field,but also promote the separation of electrons and holes and improve the efficiency of the redox reaction.In this paper,three MXene catalysts are prepared for plasma catalytic denitrification,and the synergistic mechanism of various systems is discussed,which provides a powerful reference for the application research of plasma synergistic catalytic system in the field of denitrification.The main results are as follows:（1）Study on the performance of g-C₃N₄/V₂C MXene plasma synergistic catalytic denitration.The one-dimensional tubular g-C₃N₄ and the two-dimensional multilayer V₂C are combined by solvothermal method.The denitration efficiency of C/V-3 is as high as 83.3%,which is 1.2 and 2.1 times that of single g-C₃N₄ and V₂C,respectively.And the test results of XRD,FTIR,XPS,etc.show that g-C₃N₄ binds well to V₂C.SEM results show that V₂C MXene presents a good two-dimensional layered structure,while g-C₃N₄ presents a tubular structure similar to a one-dimensional hexagonal column.TG results show that V₂C has relatively thermal stability,which is conducive to the progress of the reaction.Electrons in the conduction band of g-C₃N₄ are transferred to the valence band of V₂C due to the built-in electric field,and holes are formed in the valence band,which significantly enhances the separation of electrons and holes.（2）Research on the performance of MIL-88A（Fe）/V₂C MXene plasma synergistic catalytic denitration.By constructing a needle-like MIL-88A-Fe and two-dimensional layered V₂C MXene composite catalyst with a regular hexahedral structure and applying it to plasma denitration,the denitration performance and reaction of MIL-88A-Fe/V₂C MXene-NTP are analyzed Mechanism,the results confirm that the denitration performance of this composite catalyst has been improved.A Schottky barrier is formed between V₂C and MIL-88A（Fe）,which can effectively accelerate electron transfer.Because the Fermi level of V₂C MXene is much lower than that of other semiconductors,V₂C can act as an electron acceptor,which leads to the accumulation of a large numbers of electrons on the surface of V₂C,and holes are generated in the valence band of MIL-88A（Fe）.The depletion layer maintains the separation of carriers.With the accumulation of holes on MIL-88A（Fe）,a Schottky junction is formed on the interface,blocking the entry of electrons.Moreover,when the electrons generated by plasma discharge enter V₂C from MIL-88A（Fe）across the interface,they do not accumulate,but form a drift current and flow away directly.（3）Research on the performance of MIL-88A（Fe）/MIL-100（Fe）/V₂C MXene plasma synergistic catalytic denitration.A three-way catalyst is constructed to achieve plasma denitration performance.Compared with the effects of V₂C and NTP alone,the efficiency is 76.77%and 64.43%higher.The results of SEM,XRD,BET,ESR,XPS,etc.show that the activation of NTP makes MIL-88A（Fe）/MIL-100（Fe）form a fixed coordination layer.This dense layer helps to improve the catalytic activity of plasma denitration.After the plasma discharge,the electrons are excited in the organic linker,and then the electrons are transferred on the iron（III）oxide clusters.Therefore,MIL-100（Fe）and MIL-88A（Fe）may participate in the transfer of carriers.Then the effective separation of electron-hole pairs is achieved,which leads to more photo-generated holes for enhancing the removal of NO by the MIL-100/MIL-88A（Fe）catalyst.The research results in this paper show that MOFs can be used as a super-efficient gas adsorption material and have broader applications in the field of environmental protection in the future.