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利用吸附相反应技术制备弱紫外光响应的高效催化剂,并通过XRD、XPS以及HRTEM探索了不同焙烧温度下La3+掺杂量对TiO2结晶过程的影响.结合弱紫外光下甲基橙的降解反应,深入研究催化剂结晶过程的变化对弱紫外光下催化剂活性的影响.结果表明,La3+掺杂会抑制TiO2的结晶过程.当焙烧温度或者掺杂量较低时,La3+不能进入TiO2的晶格结构但会轻微地抑制TiO2的结晶过程;未进入晶格结构的La3+存在会引入光生载流子的浅能级捕获中心,在弱光体系中极大提升了催化剂的活性.当La3+的掺杂量为0.05%(原子分数)时,经过900℃焙烧后催化剂降解能力最高,其活性超过商用P25的2倍多.在较高La3+掺杂量(超过0.20%)时,900℃焙烧后一定量La3+进入TiO2的晶格结构而大大抑制了TiO2结晶;这种强烈的抑制作用使得催化剂中存在大量无定形结构TiO2,无定形TiO2甚至多于700℃焙烧后的催化剂,反而大大抑制了弱光体系中催化剂活性.
The effect of La3 + doping amount on the crystallization process of TiO2 was investigated by XRD, XPS and HRTEM. The degradation of methyl orange by weak UV light was studied. The effect of the change of catalyst crystallization process on the activity of catalyst in weak UV light was studied in detail.The results showed that La3 + doping inhibited the crystallization process of TiO2 and La3 + could not enter the lattice structure of TiO2 when the calcination temperature or doping amount was low Will slightly inhibit the crystallization process of TiO2; the absence of La3 + into the lattice structure will introduce shallow carriers of photogenerated carriers, which greatly enhances the activity of the catalyst in weak light system.When La3 + doping amount is 0.05% (atomic fraction), the highest catalytic activity was obtained after calcination at 900 ℃, which was more than twice as much as that of commercial P25. At the higher La3 + doping content (over 0.20%), a certain amount of La3 + TiO2 lattice structure and greatly inhibited the crystallization of TiO2; This strong inhibition makes the presence of a large number of amorphous TiO2 catalyst, amorphous TiO2 even more than 700 ℃ after calcination of the catalyst, but greatly suppressed The catalyst system activity in weak light system.