摘要
人们一直期望得到像固氮酶那样的化学固氮体系,使大气中的氮和水在常温常压下转变成氨。但是,由于这是一个热力学上不能自发进行的反应,难以实现。如果将光能引入这一反应体系中,则有可能实现这一反应。Guth等首先报道了在掺Fe_2O_3的TiO_2粉末上光催化氮的还原反应.这一反应实际上包含着两个基本反应:(1)水的氧化放氧反应,(2)氮的还原质子化反应。总的反应为:
The pholocatalytic reduction of nitrogen to ammonia in gas-solid phase and in aqueous medium on TiO2 powder by UV light irradiation was investigated.The effects of different treatment methods and different crystalline forms of TiO2 powder on photocatalytic activity for nitrogen reduction to ammonia were evaluated. TiO2 powder treated by different methods gave different crystalline forms and showed different activities. The better photocatalytic activity was obtained when TiO2 powder was treated under hydrogen atmosphere, degassed in vacuum, or doped with Fe2O3. It is suggested that the pholocalalylic activity is concerned with the formation of electronic donor centre or coordinated unsaluration centre on the surface of TiO2 powder during above-mentioned treatmenls.
