Controlled Preparation And Photocatalytic Performance Of Ordered Mesoporous Titanium Oxide And Cadmium Sulfide

The energy and ecological environment crisis caused by the excessive consumption of traditional fossil energy have become a serious problem all over the world.The emergence of semiconductor photocatalysis technology can convert the abundant solar energy into clean,efficient and sustainable hydrogen energy.Meanwhile,organic water pollutions can also be efficiently degraded by photocatalysis.In the process of photocatalytic hydrogen production and degradation of organic pollutions,the preparation of highly efficient catalysts is the key.By controlling the composition,structure and morphology of the photocatalyst,the photocatalytic activity of the photocatalyst can be effectively improved by the enhancement of the light capturing ability and transport and separation efficiency of photogenerated electrons and holes.Considering the above three aspects,we designed and synthesized a series of mesoporous TiO2,TiO2-a-Fe2O3 heterojunction and CdS and studied the mesoscopic structure and structure-activity relationship between catalytic performance of the mesoporous TiO2,TiO2-a-Fe2O3 heterojunction and CdS the main contents are as follows:A series of mesoporous TiO2 and TiO2-?-Fe2O3 heterojunctions were prepared using KIT-6 as template and fresh titanyl nitrate and ferric nitrate nonahydrate as precursors.The results show that:(1)The low hydrothermal temperature-template has a small pore size and poor connectivity.As the hydrothermal temperature increases,the pore size of the template becomes larger and the connectivity become better.After removing the template,the specific surface area of the mesoporous TiO2 was reduced from 214 m2 g-1 to 164 m2 g-1,and the pore diameter was also reduced from 12.1 nm to 3.9 nm.During the photocatalytic degradation of methylene blue,the mesoporous TiO2-40 with high specific surface area and large pore has the best ability of adsorption and photocatalytic degradation of methylene blue.(2)The mesoporous TiO2-?-Fe2O3 heterostructure is significantly enhanced in photocatalytic degradation of norfloxacin compared to mesoporous TiO2 under ultraviolet or visible light.The experimental results show that the formation of TiO2-a-Fe2O3 heterostructure effectively enhances the separation efficiency of electron-hole pairs thereby improving the photocatalytic performance of the material.A series of mesoporous cadmium sulfide(CdS)were also synthesized using KIT-6 as template and cadmium thiolate as precursor.The pore size and connectivity of the KIT-6 are gradually increased with the hydrothermal temperature.The photocatalytic hydrogen production results showed that CdS-40 with high specific surface area and double mesopores has the best photocatalytic hydrogen production activity(3.17 mmol h-1 g-1)under visible light,which is 18.7 times that of commercial CdS.Pt was deposited on the surface of the mesoporous CdS by photoreduction.The effect of loading amounts of Pt on the photocatalytic hydrogen production activity of mesoporous cadmium sulfide was studied.When 3wt%of Pt is deposited,the photocatalytic hydrogen production activity is the best(13.1 mmol h-1 g-1),which is 77.5 times that of commercial cadmium sulfide hydrogen production activity(0.169 mmol h-1 g-1).