Research On Directional Construction Of Active Sites In TiO₂ Nanotubes For Photocatalytic Water Splitting

With the over-consumption of global energy and the aggravation of environmental pollution,the pursuit of renewable,safe clean energy to reduce the pressure of environmental pollution and energy scarcity is a continuous focus of today’s society.Using semiconductor materials as catalysts,photocatalytic splitting water to convert solar energy into clean and efficient hydrogen energy has broad application prospects.The semiconductor titanium dioxide（TiO₂）material has received extensive attention in the field of photocatalysis due to its excellent stability,safety and non-toxicity.TiO₂ has a weak response in the visible light region,and the photogenerated carriers recombine rapidly,so the photons cannot be used most efficiently.In this paper,titania nanotubes（TiO₂ NTs）were prepared by a template method,Ag nanoparticles was directionally loaded inside or outside the tube of TiO₂ NTs,and the wall thickness of the TiO₂ NTs was regulated.The Ag-supported TiO₂ NTs were analyzed by XRD,SEM,FT-IR,Raman and other characterization methods,and their photocatalytic performance for splitting water to produce H₂ was tested,revealing the reasons and mechanisms for the enhanced photocatalytic activity.The main research conclusions are as follows:1.Using carbon nanofibers（CNFs）as template and tetrabutyl titanate as titanium source,TiO₂ NTs were prepared by immersion growth heat treatment method,and the tube wall thickness of TiO₂ NTs was effectively controlled by adjusting the concentration of titanium source and the number of immersion times.2.Using carbon nanofibers（CNFs）as template and tetrabutyl titanate as titanium source,TiO₂ NTs were prepared by immersion growth heat treatment method,and the tube wall thickness of TiO₂ NTs was effectively controlled by adjusting the concentration of titanium source and the number of immersion times.3.The directional loaded TiO₂ NTs of nano-Ag particles extend the visible light absorption response,and the plasmonic resonance effect of nano-Ag enhances the photo response.Ag nanoparticles are loaded on the inner and outer walls of TiO₂ NTs tubes to achieve effective spatial separation of hydrogen evolution（HER）active sites and oxygen evolution（OER）active sites,prolong the lifetime of photogenerated carriers,and enhance the photon conversion efficiency.The tube wall thickness of TiO₂ NTs is 90 nm,the rate of decomposing water to produce H₂ under visible light with TiO₂ NTs loaded inside and outside Ag reaches the maximum value of 0.7235 mmol/g/h.