Pd deposition on TiO2(110) and nanoparticle encapsulation

被引:9
作者
Bowker, Michael [1 ,2 ]
Sharpe, Ryan [1 ]
机构
[1] Cardiff Univ, Cardiff Catalysis Inst, Sch Chem, Cardiff CF10 3AT, S Glam, Wales
[2] RCaH, Rutherford Appleton Lab, UK Catalysis Hub, Harwell OX11 0FA, Oxon, England
来源
CATALYSIS STRUCTURE & REACTIVITY | 2015年 / 1卷 / 03期
基金
英国工程与自然科学研究理事会;
关键词
Nanoscience; Catalysis; Model catalysts; Nanoparticles; Encapsulation;
D O I
10.1179/2055075815Y.0000000008
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The effect of sputtering, annealing and oxidation on the surface properties of TiO2(110), and on the same surfaces with nanoparticles present, has been investigated. Sputtering the crystal clean gives a much reduced surface with Ti2+ as the dominant species. This surface is mainly Ti-3+,Ti-4+ thorn after annealing in vacuum. Oxidation reduces the surface Ti3+ considerably. When Pd nanoparticles are annealed on any of the investigated titania surfaces, the particles become encapsulated by a film of titanium oxide. This is particularly noticeable in ion scattering spectroscopy (ISS) where the Pd: Ti ratio drops by a factor of 300 after annealing to 750 K, indicating complete coverage of the Pd nanoparticles by the oxide film. This happens most easily for the nanoparticles deposited on the reduced surfaces (beginning at similar to 673K) but also occurs for the very oxidized surface at similar to 773 K. Thus, reduced Ti from the subsurface region can migrate onto the Pd surface to form the sub-oxide, the sub-oxide being a thin TiO-like layer.
引用
收藏
页码:140 / 145
页数:6
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