Study On Multiple Photocatalysts Preparation And Photocatalytic Performance Of Zeolite Imidazole Cage Confined Metal/Metal Oxide

In recent years,the water environmental pollution has been increasing due to widespread usage of organic pollutants,which has become one of the most important factors threatening human health.In response to the strategic call for the construction of ecological civilization in China,the management of organic pollutants in environmental water has become an urgent task.How to deal with the problem of water pollution has become a common concern of public thinking.Based on this,researchers are committed to finding an efficient and secondary pollution-free strategy to reduce the harm caused by pollutants to the water environment Notably,photocatalysis as an environmentally friendly green technology is considered to be one of the effective ways to solve such problems.However,researchers have been more interested in constructing multiple photocatalysts to enhance their photocatalytic activity,ignoring the key scientific question of how to construct active sites in conventional materials.In this paper,a series of zeolite imidazole cages with good stability,precisely tunable structure and regular pore channels were used as confined carriers,and a series of zeolite imidazole cage confined metal/metal oxide photocatalysts materials were prepared by means of encapsulation and doping.The effects of composition,structure and confined effects of the prepared photocatalytic materials on the stability,selectivity,active sites and ability to capture light of the photocatalysts were investigated by combining various characterization techniques.The mechanism of catalyst activation targets and photocatalytic degradation of pollutants in different systems were discussed.The main research contents and results of the paper are summarized as follows:(1)Z-scheme Ag@ZIF-8/g-C3N4 composite photocatalysts were prepared by an in-situ impregnation reduction self-assembly method using Ag as the active site and zeolite imidazole framework-8(ZIF-8)as the carrier.The prepared materials exhibited efficient degradation(>90%)of all ten antibiotics under visible light-driven.The excellent photocatalytic performance depends on the confined effect of ZIF-8 regular pores on Ag+ in the composites and the successful construction of Z-scheme heterojunctions.Among them,the assembly of Ag@ZIF-8 enhances the light harvesting ability and adsorption ability of the material while exposing more active centers,and the Z-scheme heterojunction formed between Ag@ZIF-8 and g-C3N4 enhances the separation of photogenerated carriers and the redox ability of the photocatalyst surface.This work presents a novel and effective strategy to modulate the ZIF-8 energy band and provides a new idea for the preparation of photocatalysts with integrated adsorption and degradation functions.(2)The heterojunction photocatalyst Cu2O@ZIF-8/Ti3C2 with yolk-shell structure was constructed by the template method using Cu2O as the catalytic active center,zeolite imidazole frameworks-8(ZIF-8)as the carrier and Ti3C2 as the co-catalyst The confined of ZIF-8 on Cu2O protected the stability of Cu2O and enhanced the catalytic activity of Cu2O-based mimetic enzyme.Combination of co-catalyst Ti3C2 and Cu2O@ZIF-8 heterojunction achieves efficient separation of photogenerated carriers.The optimized materials showed excellent selectivity for the hydrolysis of bovine serum albumin(BSA)under mild conditions.The efficiency of hydrolysis of BSA was 96%within 60 min.The radical capture experiments confirmed that ·O2-,h+ and ·OH are all active species in the catalytic reaction process.The excellent photocatalytic activity was attributed to the protection of the active center by caged ZIF-8,the expansion of the light absorption range and the formation of directed electron transfer channels.This work provides new ideas for the preparation of more Cu2O-based mimetic enzyme composites for solar energy conversion.(3)The HE-ZIF/ZnIn2S4 photocatalysts were constructed by mechanical ball milling method with electrostatic self-assembly strategy using metal ions in high-entropy ZIF as the active center.The results showed that the prepared photocatalyst could remove tetracycline and rhodamine B efficiently,and the degradation and removal of RhB by the optimized material was 95.8%in 10 min and 93.9%in 60 min for real TC.The excellent photocatalytic performance is not only attributed to the unique "cocktail effect" of the high-entropy material and the synergistic effect with ZnIn2S4,but also to the unique carrier separation ability of HE-ZIF and ZnIn2S4 Z-scheme heterojunction.The radical trapping experiments demonstrate that ·O2-and h+ are the main active species.This work provides new insights into the photocatalytic applications of high-entropy materials.(4)The coupling complexes of nitrogen-doped hollow carbon tubes with MoO3-x were prepared based on the derivatization strategy of zeolite imidazole framework materials in this chapter.The results show that the MoO3-x light absorption sidebands are significantly red-shifted and the light absorption intensity is enhanced significantly by the construction of oxygen vacancies,and secondly,the visible light capture ability of the composites is enhanced again to a certain extent by relying on the unique photothermal absorrption and conversion of the derivatized carbon materials.Efficient degradation(>90%)of both targets(rhodamine B and methylene blue)could be achieved within 60 min.The radical capture experiments demonstrate that ·OH and h+ are the main active species.This work not only highlights the advantages of the derivatization strategy of ZIFs,but also elucidates the important role of the construction of oxygen vacancies in enhancing the light absorption and suppressing the carrier complexation of the materials.