Study On Modification Of MOF-199 Derived Porous Carbon And Its Performance For Removal Of Organic Pollutants

Metal-organic frameworks（MOFs）have been used in many fields due to their large specific surface area,high porosity and abundant active sites.The MOFs-derived porous carbon materials obtained by directly calcining MOFs not only inherit the characteristics of MOFs materials,but also have good electrical conductivity and stability.Therefore,they have attracted people’s attention in the field of photocatalysis.However,MOFs and their derived porous carbon materials often have a large band gap and are not easily excited under visible light irradiation,resulting in lower photocatalytic performance.An effective strategy is to use semiconductor modification to improve performance.Therefore,this paper combinesα-Fe₂O₃,BiVO₄ and MOFs-derived porous carbon to obtain an efficient photocatalyst.The specific research results are as follows:Firstly,MOF-199 was synthesized in this paper,and then porous carbon material Cu@C was prepared by high-temperature roasting method,andα-Fe₂O₃ was combined with Cu@C to prepare a series ofα-Fe₂O₃/Cu@C photocatalysts.X-ray diffraction（XRD）,laser Raman spectroscopy（LRS）,scanning electron microscope（SEM）,transmission electron microscope（TEM）and X-ray photoelectron spectroscopy（XPS）were used to analyze the physical and chemical properties of the samples,revealing the formation ofα-Fe₂O₃,Cu₂O,Cu and porous carbon in the catalyst.In addition,the capture experiment and band edge position analysis show that a p-n heterojunction is formed betweenα-Fe₂O₃ and Cu@C,and the degradation mechanism of Rhodamine B（Rh B）is suggested.Under visible light irradiation,adding 10 mg ofα-Fe₂O₃/Cu@C800-2 composite photocatalyst can degrade 96%Rh B within 180 minutes,and use high-performance liquid chromatography-mass spectrometry（HPLC-MS）for analysis the reaction process and path of Rh B are described.Secondly,on the basis of the above-mentioned research work,this paper successfully prepared the BVO/Cu@C composite photocatalyst by compounding BiVO₄（BVO）and Cu@C,and systematically investigated the calcination temperature and the amount of BVO added.The characterization results of SEM,TEM,fluorescence spectroscopy（PL）,ultraviolet-visible diffuse reflectance（UV-vis DSR）and photocurrent response prove that the thin-shaped BiVO₄ is attached to the porous carbon Cu@C surface,and its introduction also forms p-n heterojunction accelerates the separation and transfer of photo-generated electron-hole pairs,inhibits the recombination of photo-generated carriers,and promotes the improvement of photocatalytic performance.Under visible light irradiation,adding 5mg of BVO/Cu@C800-3 composite photocatalyst can completely degrade TC within 90minutes,and further suggest the photocatalytic degradation route of TC based on the results of HPLC-MS.