Mascolo G, Comparelli R, Curri M L, Lovecchio G, Lopez A, Agostiano A
Istituto di Ricerca Sulle Acque, Consiglio Nazionale delle Ricerche, Via F. De Blasio 5, I-70123 Bari, Italy.
J Hazard Mater. 2007 Apr 2;142(1-2):130-7. doi: 10.1016/j.jhazmat.2006.07.068. Epub 2006 Aug 3.
The photocatalytic efficiency of supported TiO2 nanoparticles (mean size 6 nm), immobilized onto the inner walls of a cylindrical glass photoreactor was compared versus the performance of conventional TiO2 Degussa P25 catalyst. For this purpose the degradation of methyl red dye was used as evaluation test. The obtained results showed that the TiO2 Degussa P25 catalyst is more efficient than the supported nanoparticles. The poorer performance of the nanosized catalyst can be ascribed to the fact that the immobilization procedure turns out, in spite of the extremely high surface to volume ratio, in an overall reduction of active surface area available for target molecule adsorption, due to the low porosity of the supported catalyst layer. The kinetics of the investigated processes were monitored and a study on the reaction products and intermediates was carried out in order to evaluate possible difference in the reaction pathway in presence of immobilized nanoparticles versus suspended catalyst. The results demonstrate that the mechanisms of parent dye degradation in presence of supported TiO2 nanoparticles are the same as those occurring in presence of TiO2 Degussa P25 catalyst. The present work describe the results obtained on the feasibility of scaling up the colloidal nanocrystal-based photocatalysis experiment: the comparison with a well standardized degradation method performed with a known material can allow a realistic evaluation of the advantages and the limits of the investigated nanoparticle towards the ultimate technology transfer.
将负载型TiO₂纳米颗粒（平均尺寸6纳米）固定在圆柱形玻璃光反应器内壁上，与传统的TiO₂德固赛P25催化剂的性能进行了比较。为此，以甲基红染料的降解作为评估测试。所得结果表明，TiO₂德固赛P25催化剂比负载型纳米颗粒更高效。纳米催化剂性能较差可归因于这样一个事实：尽管表面体积比极高，但由于负载型催化剂层孔隙率低，固定化过程导致可用于目标分子吸附的活性表面积总体减少。监测了所研究过程的动力学，并对反应产物和中间体进行了研究，以评估存在固定化纳米颗粒与悬浮催化剂时反应途径可能存在的差异。结果表明，存在负载型TiO₂纳米颗粒时母体染料的降解机制与存在TiO₂德固赛P25催化剂时相同。本工作描述了在扩大基于胶体纳米晶体的光催化实验可行性方面所获得的结果：与用已知材料进行的标准化降解方法进行比较，可以对所研究的纳米颗粒在最终技术转移方面的优势和局限性进行实际评估。
