Fabrication And Properties Of Silver And MOF Composite Films Based On Two-Dimensional Colloidal Crystals

At present,the problem of ecological environment pollution has become increasingly prominent,such as air pollution,water pollution,which seriously threatens human producti on and sustainable development.It is imperative to address these issues and ensure the environment in which people rely for survival.Two-dimensional colloidal crystals(MCC),which have high color saturation,non-toxicity and non-fading,simple preparation process,low price,easy control of film-forming structure,easy modification of individual structural units,good reproduci bility and unique optical properties.Metal-organic frameworks(MOFs),which have a large specific surface area,high porosity and abundant active sites.Silver nanoparticles(AgNPs),which have good catalytic activity and electrical conductivity and are abundant compared to other precious metals.The combination of the three and the development of new functional membrane materials has attracted widespread attention from researchers.However,there is no significant breakthrough in the field of optical sensing and catalytic degradation,and such binding is mostly limited to powdered materials,which are not easily separated and recovered in practical applications and can easily lead to secondary contamination.In this paper,PS@Ag@ZIF-8 composite films and PS@ZIF-8/Ag ordered arrays with two-dimensional colloidal crystals as templates were prepared by in situ growth method.The formation process was explored,and the optical sensing and catalytic degradation properties were characterized and investigated,respectively.1.Facile Fabrication of Ultrathin PS@Ag@ZIF-8 film for Volatile Organic Compounds DetectionIn this work,we prepared an efficient optical sensor device by sequentially coating AgNPs and MOF films on the surface of MCC by in situ growth method.The sensor can output optical signals efficiently and precisely according to the change of the effective refractive index of the structure under the monitored environment.It is shown that we have improved the color saturation of the structure by introducing a low refractive index substance,silver,through in situ growth method.This device exhibits selective spectral response to alcohols and acetonitrile,and we found that the type and concentration of vapors can also be visually identified by significant diff erences in optical photo color by the naked eye.The sensor has an extremely fast response rate(<4 s)to the analytes to be measured,and has a good linear response concentration range and cyclic reversibility.The sensor developed in this work has significantly improved its detection performance for VOCs,providing ideas for AgNPs and MOFs in sensor design and application.2.Construction of PS@ZIF-8/Ag functional membrane and degradation performance studyIn the present work,we prepared PS@ZIF-8/Ag functional membrane structures on glass substrates by in situ growth method to achieve efficient catalytic degradation of 4-nitrophenol(4-NP)and rhodamine B(Rh B).In the presence of Na BH4(9 m L,0.38 mol/L),the catalyst could a chieve 90% degradation of 4-NP(9 m L,0.18 mmol/L)at 10 s and almost 100% degradation within 1 min.We also explored the effects of ZIF-8 content,AgNPs content,and initial concentration of 4-NP on the degradation of 4-NP by the catalyst.In addition,the functionalized PS@ZIF-8/Ag membrane structure prepared on a glass sheet substrate overcomes the disadvantages of powdered catalysts and is easy to be recycled and manipulated in practical applications,which has high economic value.This study provides certain theoretical significance for the application research of solid substrate membrane structure in the remediation of environmental water pollution.