Syntheses,Structures And Photocatalytic Properties Of Lanthanide-Titanium Oxo Clusters

Research shown that lanthanide-TOCs can be applied to light,electricity,magnetic properties and better catalytic activity due to existing lanthanide cations,which could effectively combine the advantages of rare earth and titanium.The reported lanthanide-TOCs were used single carboxylic acid or alcohol as the ligands,which lead to poor stability,lower nuclearities and simple properties.Based on the above,we explored the synthesis conditions of lanthanide-TOCs and synthesized a series of crystals,then investigated their structure and photocatalytic properties.The main contents are as follows:?:A series of lanthanide-TOCs,Ln₂Ti₄?1-12?,were synthesized through the solvothermal method with salicylic acid ligand,rare earth salts and Ti?OiPr?₄.The UV-vis proved that the band gaps for?1-12?were all smaller than P25?3.2eV?.Hence we used these clusters work as catalysts in photocatalytic experiment without adding any sensitizer and co-catalyst in 10%methanol aqueous solution.The photocatalytic properties of 1-12 revealed that their photocatalytic properties are significantly better than P25,at least 3.4 times.Especially Ln₂Ti₄?4?which coordinated with 5-fluoro-salicylic acid would provide the best performance.Hydrogen production efficiency is up to 780?mol·g-1·h-1,which is 13 times of commercial P25.It also had good stability and circularity in photocatalytic water splitting.?:Two lanthanide-TOCs,LasTi₆?13?and GdsTi₆?14?were synthesized through the solvothermal method with 5-chloro-salicylic acid ligand,rare earth salts and Ti?OiPr?4.Meanwhile,the lanthanide-TOCs,Tb₂₂Ti₁₄?15?,which presents maximum nuclear number is synthesized by adjusting the proportion of materials.We found the ligands ratio would influence lanthanide-TOCs' nuclearity in the same conditions.with the Ti?OiPr?₄ and Ln?Ac?₃ ratio gradually decreasing,the structure of the clusters will gradually get bigger,which lead us to successfully get another 36 nuclear lanthanide-TOCs Eu₂₂Ti₁₄.?:In chapter 3,Various lanthanide-TOCs include Ln₂Ti₄?16-18?,Eu₁Ti₁₃?19?,Nd₂Ti₁₃?20?,Ln)4Ti)2?21-22?were synthesized through the solvothermal method with small molecule carboxylic acid or alcohol ligand,rare earth salts and Ti?OiPr?4.Ln₂Ti₄ which have same structure but different number of nuclear were compared.Then,the photocatalytic?1,17?and photoelectrochemical properties?16,18?of Ln₂Ti₄ were investigated.The results showed that their properties were similar,and the photocatalytic efficiency of?1,17?was about 6 times higher than that of P25,and the photoelectric current density of?16,18?after illumination was about 5 times higher than that of the dark.