Preparation And Applications Of The Inorganic Layered Compound Complexed With Cationic Pigment

Organic-inorganic intercalation compounds are a unique type of materials, in which the organic guest species are intercalated into a crystalline nanoscale inorganic host lattice through some processes such as ion-exchange. What is interesting is that after intercalation, the structural integrity of the host lattice is still retained, and the featured intercalation structure and the host-guest interaction usually endow the intercalation compounds with prominent properties. By intentionally choose and assembly of the host and guest species, various kinds of layered nanocomposite can be synthesized, and may find applications in heterogeneous catalysts, devices for non-linear optics, sensors, ionic conductors, absorbents, flame retardants, structural materials, etc.In this dissertation, two kinds of cationic dye, methyl viologen (MV) and methylene blue (MB), and two metal porphyrins, FeⅢTMPyP and MnⅢTMPyP, were chosen as guest materials, layered metal oxide semiconductors (K4Nb6O17、KNb3O8、KTiNbO5、KLaNb2O7、 V2O5) were chosen as host materials to synthesize eleven novel organic-inorganic layered nanocomposites. XRD, elemental analysis, FT-IR, UV-vis、SEM and TEM techniques were utilized to characterize the structures, properties and morphologies of the nanocomposites, the electrochemical properties were investigated by use of cyclic voltammetric technique. The application possibilities of the nanocomposites were explored by testing the catalytic, electroatalytic and phothochemistry activities.MV and MB were intercalated into the interlayers of K4Nb6O17, KNb3O8, KTiNbO5and KLaNb2O7to obtain six intercalation composites, the structural models of the composites were proposed by use of the XRD and elemental analysis data. The host cations formed single or double molecular layer between the inorganic nanosheets with the molecular plane somewhat inclined to the host layers. CV graphs demonstrated that the composites maintained the electrochemical properties of the guest ions, but the electrochemical activities and stabilities of the guest differed owing to the structures and properties of the host layers. Among the six composites, the cations intercalated KLaNb2O7demonstrated excellent electrocatalytic activities. Briefly, the MV2+-LaNb2O7/GCE had good electrocatalytic oxidation upon NO2-, the linear detection range of NO2-was2×10-5～4.88×10-3mol/L with a detection limit of1.8×10-5mol/L. A novel biosensor MB+-LaNb2O7-GOD/CTS/GCE was constructed for glucose determination in neutral buffer solution, the linear detection range of glucose was2.5×10-5～2.83×10-3mol/L and the detection limit was2.0×10-5mol/L, the intercalated MB+served as a good electron mediator in the novel biosensor. The photoelectrochemical behaviors of the MV intercalated composite were examed, it was found that UV irradiation caused the electron transfer from the niobate layers to MV2+to form MV+radical cation and (MV)22+spin-paired radical cation dimer in MV2+-Nb6O17. The influences of the nanocomposites structures on the electrocatalytic and photoelectric conversion behaviors were discussed.FeⅢTMPyP and MnⅢTMPyP were intercalated into interlayers of KNb3O8and KLaNb2O7to obtain four intercalation nanocomposites. SEM graphs demonstrated that the layered mophologies were not destroyed by intercalation reaction; however, the layers were mostly dispersed. From the XRD and elemtental analysis data we proposed that the metal porphyrin formed an inclined monolayer with respect to the inorganic laminate. The four intercalation nanocomposites had excellent electrocatalytic activities upon oxygen reduction in neutral buffer solution, which is benefitted from the intercalated metal porphyrin cations. Besides, the FeⅢTMPyP-Nb3O8/GCE had unique electrocatalytic reduction on H2O2and oxidation on ascorbic acid (AA), and could be used for quantitative detection, the detection limits were1.75×10-6mol/L for H2O2and4.2×10-5mol/L for AA, respectively. MnTMPyP-LaNb2O7/GCE had good electrocatalytic oxidation on NO2-even better than MV2+-LaNb2O7/GCE. with linear examination area of2×10-5～2.14×10-2mol/L and detection limit of1.3×10-5mol/L. The electrocatalytic mechanisms were speculated and the application potential of the above nanocomposites in electrochemical sensors was proposed. The catalytic performance of FeⅢTMPyP-Nb3O8and MnⅢTMPyP-Nb3O8nanocomposites for selective epoxidation of cyclohexene was studied. The nanocompostes exhibited much higher selectivity on the epoxidation despite the lower conversion rate, besides, the catalytic activities and selectivity remained appreciable after several recycles.MB was intercalated into layered V2O5through the redox reaction of I-with V2O5followed by electrostatic reaction of the MB+with the reduced V2O5layers. The intercalated MB cations showed a well defined electrochemical redox process and facilitated the immobilized horseradish peroxidase’s (HRP) good catalytic reduction upon H2O2. The as-prepared MB-V2O5/HRP/GCE biosensor showed a linear response to H2O2over a range from2.0×10-6to9.5×10-5mol/L with a detection limit of1×10-6mol/L. The reaction mechanism of the biosensor was proposed.