Study On Preparation And Modification Of Nanometer TiO₂ And Hydrogen Production From Photolysis Water

This article focuses on the preparation of TiO₂ catalysts with different morphologies by hydrothermal synthesis.And TiO₂ catalysts were characterized,tested on hydrogen evolution.Through preliminary screening,some TiO₂ with better catalytic effect was modified,and different noble metals were loaded to further improve its photocatalytic performance.The main content is divided into the three following parts.Firstly,different titanium sources are used to prepare TiO₂ catalysts with different morphologies by hydrothermal synthesis,including nanospheres,nanosheets,nanoflowers,nanorods,and ultrathin nanosheets.Then,photocatalytic reduction is used to modify them supported metal.And TiO₂ catalysts were characterized,tested on hydrogen evolution.The ultra-thin nanosheet TiO₂is selected.Through characterization analysis,the ultra-thin nanosheet TiO₂ has extremely thin morphology,the thickness is within 2nm and the morphology is more flexible and curled.Secondly,although TiO₂ is superior photocatalytic performance,stable chemical properties and cheap,there are low solar energy utilization rates in practical applications,photoresponse only in the ultraviolet region,and low recycling rapid（e^--h⁺）recombination.The ultra-thin nanosheet catalyst was modified by a photocatalytic reduction method,and supported three different precious metals,Pt,Pd,and Ag.Three series of catalysts Pt-TiO₂,Pd-TiO₂,and Ag-TiO₂ were obtained,The corresponding characterization and analysis were performed,and the activity of hydrogen production by photolysis of water and catalyst stability tests were performed.The catalytic performance of the modified catalyst was significantly improved.The stability of the catalyst is also good.After 6 cycles,the yield of hydrogen production can still reach 746.43μmol*g^-1h^-1,which is only 6.7%lower than the third time with the highest yield.Thirdly,in order to study the synergistic catalysis between bismuth and TiO₂ and better improve the photocatalytic performance of this system,the Pt-Pd bimetal loading and corresponding characterization of TiO₂ ultrathin nanosheets were performed.The results of photolysis of water to produce hydrogen show that the loading effect of bimetal is better than that of single metal.Bimetal has a synergistic effect in the TiO₂ catalysis process,which promotes the effective separation of photogenerated electrons and holes and improves the catalytic effect.