Modification Of Metal Organic Framework Derived Porous Carbon And Its Photodegradation Performances

Metal organic frameworks（MOFs）derived porous carbon materials not only retain the metal active sites of MOFs materials,but also inherit the structural characteristics of high specific surface area and porosity.And,the materials present good structural stability and conductivity,triggering researchers’wide attentions.In addition,to improve the visible light response abilities of the materials,some matching semiconductors are selected to be introduced to construct hybrid catalysts,which will greatly enhance the photodegradation performances of the catalysts.Therefore,Bi VO₄（BVO）bearing suitable band edge position and narrow band gap was used to modify MOFs derived porous carbon and applied to the photocatalytic degradation of tetracycline（TC）in this work.（1）In this paper,ZIF-8 was successfully synthesized and used as a precursor to prepare porous carbon material Zn@ZPC.Also,BVO was synthesized by a hydrothermal method.Finally,a hybrid BVO/Zn@ZPC was prepared by a simple heat treatment method.The samples were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and X-ray photoelectron spectroscopy（XPS）.The results confirmed the existence of Zn O,BVO and porous carbon matrix.Low-temperature nitrogen adsorption illustrated that the specific surface area（25.3m²/g）and pore volume（0.109 cm³/g）of BVO/Zn@ZPC were significantly increased compared to those of pure BVO,and abundant pore structures were formed.In addition,UV-vis diffuse reflectance（UV-vis DSR）,Mott Schottky curves,XPS valence band spectra（VB-XPS）,radical trapping experiments and electron spin resonance（ESR）analysis agreed that a Z-scheme structure was formed between phase Zn O and BVO,and confirmed that·O₂^-was the main reactive species.In the photodegradation experiment,BVO40/Zn@ZPC600 with 600℃of calcination temperature and 40 mg of BVO introduction amount exhibited the optimum photocatalytic performance.Under visible light irradiation,5 mg catalyst could completely degrade 100 m L of TC solution（50 mg/L）within 60 min.（2）On the basis of the above work,bimetallic ZIF-8@ZIF-67 was designed and employed as a precursor to prepare porous carbon material Co Zn@ZPC,which was prepared by calcining in muffle furnace and tubular furnace,respectively.BVO/Co Zn@ZPC was further obtained by collaborating a BVO.It can be summarized via a series of physical and chemical characterization that hollow porous carbon structures were formed in Co Zn@ZPC,which boosted the utilization of visible light.And,a double Z-scheme structure was produced between Zn O,Co₃O₄ and BVO,which accelerated the transferring of photogenerated electrons and inherited the recombination of photogenerated carriers.In the photodegradation experiment,BVO50/Co Zn@ZPC with600℃of calcination temperature and 50 mg of BVO introduction amount presented the optimum photocatalytic performance.Under visible light irradiation,5 mg catalyst could completely degrade 100 m L of TC solution（50 mg/L）within 30 min.In addition,the formation of intermediate products was analyzed by liquid chromatography-mass spectrometry,and the degradation path of TC was proposed.