| Since their appearance,mesoporous metal oxides have been widely studied as catalytic materials because of their large specific surface area,abundant surface active centers,and adjustable mesoscopic structure and components.In recent years,gallium based metal oxides with d10 electronic structure and nanometer size have been widely studied because of their high electron mobility,large band gap width and more activity at nanometer size.More and more reports have reported that the sites and good electron transport ability have high stability and superior performance in the process of photocatalyzed water decomposition and hydrogen production.However,the preparation of ordered mesoporous gallium based metal oxides is still challenging.On the one hand,due to the high crystallization temperature of the stable phase formed by gallium based metal oxides,the traditional hydrothermal synthesis method is difficult to meet;on the other hand,gallium based metal oxides are vulnerable under acid and alkali conditions.When the hard template method is selected for preparation,the template and the method of etching the template are highly required.Therefore,there are few reports of ordered mesoporous gallium based oxides.Based on this,we have designed and synthesized a series of ordered large mesoporous gallium based spinel structure gallites with high specific surface area,and obtained spinel type gallium based metal oxides with different structural parameters(specific surface area,pore size or pore size distribution,pore wall thickness,particle size)and different chemical composition by adjusting and controlling.Some of them have been preliminarily discussed.The main work are listed as follows:1.KIT-6 with different structure was synthesized by hydrothermal method as template.With hydrated gallium nitrate and hydrated zinc nitrate as precursors,ordered mesoporous zinc gallinate with high specific surface area was synthesized by nano casting method.By changing the hydrothermal temperature,the pore diameter,wall thickness and connectivity of KIT-6 template are changed so as to realize the control of the mesostructure of zinc gallinate.The specific surface area can reach 137 m2/g,and the pore diameter is about 11 nm.By changing the calcination temperature and etching template conditions of the material,the influence of the material on the ordered mesoporous ZnGa2O4 mesostructure is explored.It is proved that the zinc gallinate formed after calcination at 850? has a better etching effect by heating and refluxing.When testing the photocatalytic performance,we found that the hydrogen production rate can reach 1200 ?mol/h/g as soon as possible.2.In a similar way,we changed the types of precursors.A series of ordered mesoporous cobalt gallinate materials with high specific surface area were synthesized.The results also show that the best condition to form ordered mesoporous structure of CoGa2O4 is calcination at 850?.The specific surface area is increased from 104 m2/g to 126 m2/g,and the pore diameter is increased from 10.3 nm to 12.1 nm.The photocatalytic hydrogen production performance of the synthesized material is tested and the fastest hydrogen production rate was 5800 ?mol/h/g.3.Mesoporous metal oxides such as nickel gallinate and copper gallinate were synthesized by similar methods.According to the XRD data,calcination temperature at 850? for 6 hours is the best condition for the formation of ordered mesoporous structure of nickel gallinate.By adjusting the specific surface area from 247 m2/g to 145 m2/g,and the pore diameter from 9.7 nm to 13 nm;calcination at 750? for 6 hours is the best condition for the formation of ordered mesoporous structure of copper gallinate,the specific surface area from 131 m2/g to 90m2/g,and the pore diameter from 13.5nm to 9.7nm. |
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