Controllable Synthesis Of Functional Inorganic Nanomaterials And Their Applications

With the unprecedented boom in nanotechnology and characterization methods,functional nanomaterials have attracted much attention in many fields.Thus,rational design and controllable synthesis of functional nanomaterials and their related applications are still the research hotspot in many fields.At the same time,many problems remain to be resolved.In this thesis,the controllable synthesis and application of allinorganic perovskite nanomaterials and metal-based catalysts have been studied.As a new type of photoelectric material,all-inorganic perovskite nanomaterials(CsPbX3,X=Cl,Br,I)have attracted extensive attention in various fields due to their excellent photophysical properties and promising applications.CsPbX3 nanocrystals have many advantages,which making them great candidates for diverse applications.Although excellent achievements have been made in the synthesis and application of CsPbX3 nanocrystals in recent years,there are still many problems and challenges in this field,such as poor stability of materials and low efficiency of devices,which seriously restrict the practical application.Aiming at these problems,we successfully prepared CsPbX3 nanocrystals with different morphologies and enhanced stability by using various synthetic methods.Furthermore,the application of such materials in LED has been preliminarily discussed.Metal-based catalysts have been widely used in catalysis due to their excellent physicochemical properties.Besides,the surface effect and quantum confinement effect caused by small size endow this series of material different properties compared with their bulk counterparts.The distinct properties of such materials,such as adjustable morphology and size,play a critical role in determining their physicochemical properties and catalytic properties.Nowadays,metal-based nanocatalysts have made great progress.However,there are some problems and challenges in the synthesis,such as uncontrollable morphology and particle size,unclear mechanism,low yield,high cost,time-consuming process,poor reproducibility,and so on.These issues restrict the practical application of metal-based nanocatalysts to a large extent.In this thesis,we have carried out a series of researches on the preparation method,reaction mechanism and application of metal-based catalysts.The specific researches are summarized as follows:1.Through a modified hot-injection strategy,we have successfully synthesized CsPbX3 nanocrystals by regulating the injection temperature and the reaction temperature.The as-obtained CsPbX3 nanosheets possess uniform size distribution,and their thickness can be precisely tailored on the atomic level.Caused by the smaller size compared with its Bohr radius,the quantum confinement effect makes its intrinsic optical properties appear specially.These CsPbBr3 nanosheets have been successfully applied in blue LED devices as the emitting layer for the first time,which provide a new kind of active layer for blue LED devices.2.Based on the mutual conversion characteristics between Cs4PbX6 nanocrystal and CsPbX3 nanocrystal at an oil-water interface,CsPbX3 nanorods with uniform size,unique morphology and accurate tunable aspect ratios have been successfully prepared by adjusting the concentration of Cs4PbX6 solution and the reaction time.What’s more,the conversion process has been further systematically studied.Finally,the CsPbBr3 nanorods with suitable aspect ratio,low hole injection barrier and clean surface were used as the luminescent layer in green LED devices with an external quantum efficiency of 8.2%.3.GaPt nanoalloys with narrow size distribution and tunable composition were prepared by a facial colloidal synthetic method.The GaPt catalysts prepared through this method have excellent activity and stability toward both the reaction of propane dehydrogenation to propylene and electrocatalytic oxidation of methanol due to the change of its electronic environment caused by the formation of chemical bonds between Pt and Ga atoms,resulting in a certain synergistic effect between the two elements.Above all,this work paves a way for the synthesis and alloying of Pt-based composite electrocatalysts and also provides an opportunity for the preparation and development of such materials.4.Vanadium-based catalysts have outstanding catalytic performance toward electrocatalytic functionalization of methane.Vanadium-based heterogeneous catalysts(VOPO4·2H2O nanosheets)were prepared through high-temperature refluxing.Such catalysts showed excellent catalytic performance for methane oxidation in concentrated sulfuric acid.Subsequently,the kinetic process of methane functionalization catalyzed by vanadium-based homogeneous catalyst(V-oxo)at low acid concentration was further studied.The study of acid concentration and catalyst usage provides new ideas for the design and research of high-performance catalysts.