New insights on solar photocatalytic degradation of phenol over Fe-TiO2 catalysts: Photo-complex mechanism of iron lixiviates
New insights on solar photocatalytic degradation of phenol over Fe-TiO2 catalysts: Photo-complex mechanism of iron lixiviates
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DOI：
10.1016/j.apcatb.2009.09.017
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发表时间：
2009-11
影响因子：
22.1
通讯作者：
C. Adán;A. Martínez-Arias;S. Malato;A. Bahamonde
中科院分区：
文献类型：
--
作者：
C. Adán;A. Martínez-Arias;S. Malato;A. Bahamonde
研究了铁掺杂二氧化钛催化剂制备过程中铁含量和煅烧温度对日光辅助光降解苯酚的影响。纯二氧化钛催化剂也进行了比较分析。随着焙烧温度的升高，苯酚和TOC的去除率有所提高。虽然随着煅烧温度的升高，观察到短有机酸的演化和分布有细微的差异，但在所有分析的催化剂中，苯酚的光降解显然是通过相同的氧化途径进行的。铁浸出物的光络合机制，通过溶液中还原的铁（II）离子在催化剂表面重新吸附，随后被光生成的孔重新氧化，使催化剂准备好进行新的光降解循环，已经被假设来解释所获得的结果。提出了通过形成[fe -羧酸]2+络合物从催化剂表面提取铁的方法，在此过程中，难降解的羧酸同时进一步氧化。XPS结果和化学分析结果表明，新旧催化剂的铁含量没有差异，证实了催化剂表面有铁浸出物的再吸附现象。
The influence of iron content and calcination temperature applied during catalyst preparation on the solar light assisted photo-degradation of phenol over iron-doped titania catalysts have been studied. Pure titania catalysts were also analysed for comparative purpose. An improvement in phenol and TOC removal was detected upon increasing calcination temperature. Although subtle differences in evolution and distribution of short-organic acids were observed upon increasing the calcination temperature, phenol photo-degradation apparently proceeded through the same oxidation pathway over all analysed catalysts. A photo-complex mechanism of iron lixiviates by which the reduced Fe(II) ions in solution become re-adsorbed on the catalyst surface and subsequently re-oxidized by photogenerated holes, leaving the catalyst ready for a new photo-degradation cycle, has been postulated to explain the obtained results. Iron is proposed to be extracted from the catalysts surface through formation of a [Fe-carboxylic acid]2+complex within a process in which refractory carboxylic acids simultaneously undergo further oxidation. XPS results and the absence of differences in the iron content determined by chemical analysis when comparing fresh and used catalysts confirm the re-adsorption phenomena of iron lixiviates on the catalyst surface.