Optical Properties Of Zn-Al Layered Double Hydroxides And Ni-Based Metal Organic Framework

In the past few decades,widespread attention has been focused on two-dimensional?2D?materials due to their unique structures as well as fascinating properties.Layered double hydroxides?LDHs?and metal-organic frameworks?MOFs?represent a family of 2D layered materials with tunable versatility and high stability.The highly tunable composition combined with the ability of anion exchange and intercalation allow the exploitation of a series of functions of LDHs and MOFs materials,allowing their use as catalysts and absorbents,in biotechnology and drug delivery,and as magnetic materials,as well as electroactive and photoactive materials.Herein,Zn–Al layered double hydroxides?LDHs?are proposed for the first time as highly sensitive and uniform substrates for both SERS and SEIRA.Raman and infrared spectroscopies are typical vibrational spectroscopies that have complementary selection rules,which are,in combination,highly valuable spectroscopies for the identification of structures and dynamics of molecules as well as chemical unknowns.Surface-enhanced Raman scattering?SERS?and Surface-enhanced infrared absorption?SEIRA?are being rapidly developed and widely used in many fields due to its high sensitivity and specificity.Zn–Al LDH show a remarkable SERS effect with an enhancement factor?EF?as high as 1.637×10⁴by using 4-mercaptobenzoic acid?4-MBA?as the probe molecule,where the charge transfer and hydrogen bonds are believed to result in the SERS effect.Interestingly,Zn–Al LDH also exhibit SEIRA by using 4-methoxybenzenethiol?4-MTP?,where the resultant substrates possess excellent long-term stability of up to 60 days.In addition to the application of two-dimensional semiconductor materials in spectroscopy,this thesis successfully produced nickel-based MOF nanosheets on a flexible carbon cloth substrate by hydrothermal method.In order to improve the photocatalytic activity of the material and improve the stability and uniformity,a unique core-shell nanostructured Co₃O₄/Ni-PTA composite was prepared on a flexible carbon cloth substrate by a two-step hydrothermal method.In addition,triethanolamine?TEOA?-assisted Ni-based MOF can be used as a photocatalyst for hydrogen evolution from water splitting under the near-infrared irradiation.This research pioneered the application of MOFs and its related composite materials in the field of near-infrared driven photocatalytic hydrogen production,laying a solid foundation for the future research of this material in the field of catalysis.