Study On Preparation And Energy Conversion Properties Of LDHs-Based 2D Ordered Composites

Ordered structure of molecules widely exists in both natural and artificial materials.Ordered arrangement could effectively regulate the transport of light waves,carriers,and phonons in materials and optimize the optical,electrical,and mechanical properties of materials.Ordered structure of material has a broad application in the field of energy storage,transfer and conversion.Layered double hydroxides(LDHs)are a class of2 D layered nanomaterials with many tunable properties,such as the type and proportion of frame metal ions,interlayer anions,size and morphology.With the unique layered structure of LDHs,two-dimensional ordered composites can be constructed by different methods,such as confined synthesis method and stacked assembly method.Abundant hydroxyl functional groups are uniformly located on the host layer of LDHs,providing the active site for chemical reaction,and interacting with guest molecules to affect the configuration of guest molecules.The rigid host layer of LDHs can bring a confinement space for the growth or dispersion of guest molecules or nanomaterials and realize the precise control of the morphology,structure and dispersion of guest molecules and nanomaterials.We constructed LDHs-based 2D composites with controllable structure and adjustable performance.We study the energy storage and conversion capacity of LDHs-based 2D composites,and use for matrix-assisted laser desorption ionization mass spectrometry(MALDI-MS)and thermoelectric device.1.Study on controllable preparation of LDHs matrix and applied in MALDI-MS for small molecular ionization.LDHs composites with specific composition show decent UV-light absorption capacity and energy transfer performance,which can be used as a new matrix for MALDI-MS detection.Abundant hydroxyl groups on the host layer of LDHs demonstrate the ability to selectively target hydroxyl groups in low-molecular-weight phenols,facilitating ionization of phenols and realizing interference-free mass spectra.LDHs matrix can distinguish phenols with different quantities of hydroxyl groups and their structural isomers.LDHs matrix could help to track the low-molecular-weight phenols liberated from plastics and supply spatial information for aged plastics by MALDI-MSI.It provides an effective method for tracking harmful molecule degraded from plastic.2.Study on preparation of LDHs/PSS-Ag NPs matrix and efficient utilization of laser energy.In order to solve the problem that silver nanoparticles(Ag NPs)easy to aggregate and interfere with MALDI-MS detection results.We fabricated a homogeneous film with the uniform size distribution and monodispersion Ag NPs in the confined interlayer of LDHs.The Ag NPs with advantageous UV laser absorption could realize the energy capture and transfer process,and LDHs with abundant hydroxyl groups are beneficial for the deprotonated reaction of analyte.Interferences-free mass spectra with distinguished signals,stabilized reproducibility,and high salt tolerance in negativeion mode can be successfully achieved.In addition,both liquid glucose and gaseous psoralen samples can be effectively collected and quantitatively detected by the LDHs/PSS-Ag NPs matrix.Therefore,we have proposed a new strategy for the design and construction of effective matrix for MALDI-MS,which may open viable opportunities and inspirations for fabrication of other photoactive matrixes.3.Study on preparation and thermoelectric properties of PEDOT:PSSLDHs composite film.It is important that designing and constructing ordered molecular structures to achieve advanced materials.We constructed the composite thermoelectric(TE)film with ordered structure by the 2D confned effect of LDHs.LDHs nanosheets and poly(3,4-ethylenedioxythiophene)-poly-(styrene sulfonate)(PEDOT:PSS)molecules alternative stacked to construct periodically ordered PEDOT:PSS-LDHs TE composite films.The ordered structure of PEDOT:PSS-LDHs gave rise to the extended molecular configuration of PEDOT:PSS,resulting in the improved carrier mobility in the hybrids.Moreover,the energy filtering was induced by such a periodically ordered structure,which blocked the low-energy carriers preferentially and improved the seebeck coefficient in the hybrids.Therefore,the power factor of the PEDOT:PSS-LDHs hybrid was 120-fold higher than that of pristine PEDOT:PSS.The TE device prepared by PEDOT:PSS-LDHs hybrid can distinguish electrical signals with different temperature differences.These results not only establish an effective method for the construction of periodically ordered TE materials but also address the significance of an ordered structure of molecules in TE materials.