Nanocrystalline Brookite with Enhanced Stability and Photocatalytic Activity: Influence of Lanthanum(III) Doping
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- 作者：C茅line Perego ; Yu-heng Wang ; Olivier Durupthy ; Sophie Cassaignon ; Renaud Revel ; Jean-Pierre Jolivet
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2012
- 出版时间：February 22, 2012
- 年：2012
- 卷：4
- 期：2
- 页码：752-760
- 全文大小：424K
- 年卷期：v.4,no.2(February 22, 2012)
- ISSN：1944-8252
文摘
Metastable TiO2 polymorphs are more promising materials than rutile for specific applications such as photocatalysis or catalysis support. This was clearly demonstrated for the anatase phase but still under consideration for brookite, which is difficult to obtain as pure phase. Moreover, the surface doping of anatase with lanthanum ions is known to both increase the thermal stability of the metastable phase and improve its photocatalytic activity. In this study, TiO2 nanoparticles of almost only the brookite structure were prepared by a simple sol鈥揼el procedure in aqueous solution. The nanoparticles were then doped with lanthanum(III) ions. The thermal stability of the nanoparticles was analyzed by X-ray diffraction and kinetic models were successfully applied to quantify phases evolutions. The presence of surface-sorbed lanthanum(III) ions increased the phase stability of at least 200 掳C and this temperature shift was attributed to the selective phase stabilization of metastable TiO2 polymorphs. Moreover, the combination of the surface doping ions and the thermal treatment induces the vanishing of the secondary anatase phase, and the photocatalytic tests on the doped brookite nanoparticles demonstrated that the doping increased photocatalytic activity and that the extent depended on the duration of the sintering treatment.