Structural Regulation And Catalytic Hydrogen Production Of Titanium Oxide/polyelectrolyte Composite Films

In recent years,the development of semiconductor photocatalysts is booming.The basic research and technical route of two-dimensional materials have been greatly developed,and they have also shown excellent performance in a wide range of applications.Research on photocatalysis of two-dimensional semiconductor materials is one of the ways to solve the current environmental problems,and two-dimensional titanium oxide nanomaterials?TiO₂?are also recognized as the most environmentally friendly photocatalytic materials with development prospects and application potential.Two-dimensional titanium oxide nanosheets?TNs?as semiconductor photocatalysts have the advantages of low cost,good stability,and reusability.They have been widely used in the field of photocatalysis.However,due to its high electron-hole ineffective recombination rate,low visible light utilization rate,and wide band gap,etc.,its use in photocatalytic degradation of organics and hydrogen production is limited.In order to improve the photocatalytic activity of titanium oxide nanomaterials,solve the catalyst recovery problem and meet the application requirements,this paper proposes to use layer-by-layer self-assembly?LbL?method to regularly prepare ordered[titanium oxide?TNs?/polyelectrolyte?PAH,PDDA,PLL?]organic-inorganic composite photocatalytic structure on the surface of quartz substrate,to study the mechanism of the effect of organic polyelectrolytes on the performance of inorganic titanium oxide nanosheets,to explore the synergistic effects of various components,and the performance of the composite structure.In this paper,the organic solvent swelling and peeling method is used to peel the titanate precursor synthesized by high temperature solid phase into a single layer and a small number of multilayer titanium oxide nanosheets.Using it as an assembly element,a?PAH/TNs?n binary multilayer film was successfully prepared by layer-by-layer self-assembly method with polyelectrolyte PAH.At the same time,gold nanoparticles?AuNPs?were prepared in one step by a simple citric acid reduction method,and?PAH/TNs/Au?n ternary multilayer films were prepared in the same way.Using the advantages of the layer-by-layer self-assembly method in structural design and highly repetitive structure control,the effects of the number of assembly layers n and gold nanoparticle loading on the photocatalytic performance in the composite photocatalytic structure were explored.Secondly,the polyelectrolytes PDDA and PLL with different monomer structures were substituted for PAH as the assembly element to prepare organic-inorganic composite multilayer films,and the effect of different types of polyelectrolytes on the photocatalytic performance of the composite structure was analyzed by horizontal comparison.By controlling the assembly conditions and optimizing the assembly structure,the prepared organic-inorganic composite film has good photocatalytic hydrogen production performance under visible light.It is expected to provide references for the precise control of high-efficiency catalytic structures and the application of organic-inorganic composite catalytic systems.