Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (11): 2151-2157.doi: 10.3866/PKU.WHXB201510083

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Growth, Electronic Structure and Thermal Stability of Ni on ZrO2(111) Thin Film Surfaces

Yong. HAN,Qian. XU,Huan-Xin. JU,Jun-Fa. ZHU*()   

  • Received:2015-08-06 Published:2015-11-13
  • Contact: Jun-Fa. ZHU E-mail:jfzhu@ustc.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(U1232102, 21403205);National Key Basic Research Programof China (973)(2013CB834605)

Abstract:

The growth mode, electronic structure, and thermal stability of Ni nanoparticles on thin ZrO2(111) film surfaces were investigated using X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and low-energy electron diffraction. Stoichiometric ZrO2(111) thin films with thickness of 3 nm were epitaxially grown on a Pt(111) single-crystal surface. The results indicate that the growth of Ni vapor deposited on thin ZrO2(111) films follows two-dimensional growth up to 0.5 ML (monolayer), followed by threedimensional growth (i.e., the Stranski-Krastanov growth mode). The Ni 2p3/2 binding energy (BE) increases with decreasing Ni coverage. We used the Auger parameter method to differentiate the contributions to this BE shift from the initial-state and final-state effects. The main contribution to the Ni 2p core level BE shift is made by the final-state effect. However, at low Ni coverages, the initial-state effect also contributes. This suggests that at the initial stage of Ni growth on the ZrO2(111) surface, Ni and ZrO2 interact strongly, leading to charge transfer from Ni to the ZrO2 substrate, with the appearance of partially positively charged Niδ+. Thermal stability studies of Ni/ZrO2(111) model catalysts with two different coverages (0.05 and 0.5 ML) indicate further oxidation of Ni to Ni2+ and concurrent diffusion of Ni into the ZrO2 substrate at elevated temperatures. These findings provide an atomic-level fundamental understanding of the interactions between Ni with ZrO2, which is essential for identifying the structures of real ZrO2-supported Ni catalysts.

Key words: Nickel, Zirconia, Model catalyst, X-ray photoelectron spectroscopy, Ultraviolet photoelectron spectroscopy

MSC2000: 

  • O643