Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131 Padova, Italy.
Nanoscale. 2014 Jan 21;6(2):800-10. doi: 10.1039/c3nr04623k.
Novel interface-stabilized ceria nanophases have been grown on TiO2(110) by physical vapor deposition. At low coverage, dumbbell nanostructures constituted by reconstructed titania and ceria clusters are formed, while long range ordered nanoxides can be obtained by increasing the ceria dose. Scanning tunneling microscopy and photoemission spectroscopy were used to characterize the electronic properties of the films, showing that the TiO2 substrate can effectively stabilize ceria in reduced form over a wide range of experimental conditions. Epitaxial coupling is a very useful tool for tuning the chemical properties of mixed oxide systems. The special electronic properties of the films have a direct counterpart in the chemical activity, which has been investigated by temperature programmed desorption using methanol as a probe molecule. The experimental results indicate an exceptional activity of the ceria-titania interface in the selective dehydration of methanol to formaldehyde at an unprecedented low temperature (330 K).
通过物理气相沉积在 TiO2(110)上生长了新型界面稳定的氧化铈纳米相。在低覆盖度下，由重构的二氧化钛和氧化铈簇形成了哑铃状纳米结构，而通过增加氧化铈剂量可以获得长程有序的纳米氧化物。扫描隧道显微镜和光电子能谱用于表征薄膜的电子性质，表明 TiO2 衬底可以在广泛的实验条件下有效地将氧化铈稳定在还原态。外延耦合是调节混合氧化物体系化学性质的非常有用的工具。薄膜的特殊电子性质在化学活性中具有直接的对应关系，这已通过使用甲醇作为探针分子的程序升温脱附进行了研究。实验结果表明，在前所未有的低温（330 K）下，甲醇选择性脱水为甲醛时，氧化铈-二氧化钛界面具有异常高的活性。
