Preparation And Performance Study Of MOF-based Ag@AgCl Composite Photocatalyst

Metal-Organic Frameworks?MOFs?are novel organic-inorganic hybrid porous crystal materials formed by self-assembly of metal ions and organic ligands due to their adjustable porous structure,diverse morphology,and large specific surface area,open metal sites,and the ability to capture photo generated electrons to metal clusters?LCCT?to promote electron-hole separation,making this new organic porous material MOFs a place in the field of photocatalysis.Although MOFs have semiconductor behavior,their photocatalytic performance is inferior to conventional semiconductor photocatalysts.Therefore,the structural design and preparation of MOFs and the modification based on MOFs make it more excellent in photocatalytic activity.Based on the above research background,two MOFs-based composite photocatalysts were designed and constructed reasonably,and a series of researches were carried out on them:?1?ZIF-67 was synthesized by a room temperature stirring method,and a porous structure of C400 was prepared by high-temperature calcination using ZIF-67 as a template to improve the utilization of light.Then,a new high-efficiency composite photocatalyst Ag/Ag Cl/C400 was synthesized by photo-depositing Ag/Ag Cl semiconductor materials on C400 surface.Then through a series of characterization methods,the crystal structure and particle morphology of the composite photocatalyst were explored.Ag/Ag Cl/C400 still has a rhombohedral dodecahedral structure similar to ZIF-67,and the efficiency of visible light utilization is greatly improved.Since Ag/Ag Cl can generate plasmon resonance effect,which accelerates the transfer rate of photogenerated carriers on the catalyst surface and improves the separation efficiency of electron-hole pairs,it is expected to enhance the photocatalytic activity of photocatalysts.According to the results of the photocatalytic degradation of methyl orange,the composite photocatalyst Ag/Ag Cl/C400 showed the best photocatalytic activity,the photocatalytic degradation efficiency reached over 90%,and showed good stability and reproducibility.?2?Amino-functionalized MIL-101?Fe?-NH₂ material was first synthesized by solvothermal method using ferric chloride hexahydrate and 2-aminoterephthalic acid as raw materials and N-N dimethylformamide as solvent.The composite photocatalyst Ag@Ag Cl/MIL-101?Fe?-NH₂ with high efficiency of adsorption-visible light degradation was successfully synthesized by photodeposition on MIL-101?Fe?-NH₂surface with different content of Ag@Ag Cl.The crystal structure and particle morphology of several synthetic materials were explored by means of XRD,XPS,SEM and TEM.The photoelectrochemical properties of the prepared materials were analyzed by PL,EIS and photocurrent density tests.Then,the removal rate of the organic dye methylene blue was judged by the composite photocatalyst.The results show that the composite photocatalyst Ag@Ag Cl/MIL-101?Fe?-NH₂ exhibits good adsorption and photocatalytic properties under visible light.Among them,AAMN-3composite photocatalyst exhibits the strongest methylene blue adsorption-visible photocatalytic degradation efficiency,and has good stability and reusability.