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Structure–Property Relationships in the Y2O3–ZrO2 Phase Diagram: Influence of the Y-Content on Reactivity in C1 Gases, Surface Conduction, and Surface Chemistry
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-09-26 00:00:00 , DOI: 10.1021/acs.jpcc.6b07234
Michaela Kogler 1 , Eva-Maria Köck 1 , Bernhard Klötzer 1 , Simon Penner 1
Affiliation  

The C1 chemistry of Y-doped ZrO2 samples (3, 8, 20, and 40 mol % Y2O3; 3-YSZ, 8-YSZ, 20-YSZ, and 40-YSZ) was comparatively studied with respect to the correlation of electrochemical properties and surface chemistry in CH4, CO, and CO2 atmospheres by electrochemical impedance (EIS) and spectroscopic (FT-IR) methods up to 1273 K to unravel the influence of the Y-doping level. A consistent picture with respect to qualitative and quantitative surface modifications as a function of temperature and gas-phase composition evolves by performing highly correlated operando/in situ measurements. A detailed study of carbon deposition in CH4 and CO and adsorption of CO and CO2, but also proof of the strong influence of the surface chemistry, is included. Carbon deposition during treatment in CH4 and CO at temperatures T ≥ 1023 K is a common feature on all materials, irrespective of the Y content. On the 40-YSZ sample, the thinnest, but at the same time fully percolated, carbon layer was generated, and hence, “metallic” conductivity was apparent. This goes along with the fact that 40-YSZ is most unreactive toward adsorption, suggesting a direct link between homogeneous deposition and suppressed reactivity. For all Y-doped samples, temperature regions with different charge carrier activation energies could be identified, perfectly corresponding to significant changes in surface chemistry. Due to the different degree of hydroxylation and the different ability to chemisorb CO and CO2, the influence of the surface chemistry on the electrochemical properties is varying strongly as a function of Y-content.

中文翻译:

Y 2 O 3 –ZrO 2相图中的结构-性质关系:Y含量对C1气体中反应性,表面传导和表面化学的影响

对Y掺杂ZrO 2样品(3、8、20和40 mol%Y 2 O 3; 3-YSZ,8-YSZ,20-YSZ和40-YSZ)的C1化学性质进行了比较研究。 CH 4,CO和CO 2气氛中电化学性质和表面化学的相关性,通过电化学阻抗(EIS)和光谱法(FT-IR)达到1273 K来揭示Y掺杂水平的影响。通过执行高度相关的操作/原位测量,可以得到有关定性和定量表面改性随温度和气相组成变化的一致图像。CH 4中碳沉积的详细研究并且包括CO以及CO和CO 2的吸附,还包括表面化学的强烈影响的证明。在温度T下在CH 4和CO中处理过程中的碳沉积≥1023 K是所有材料的共同特征,而与Y含量无关。在40-YSZ样品上,最薄但同时被完全渗滤的碳层已生成,因此“金属”电导率显而易见。伴随着这样的事实,即40-YSZ对吸附的反应性最弱,这表明均相沉积与抑制的反应性之间存在直接联系。对于所有掺Y的样品,可以识别出具有不同载流子活化能的温度区域,这完全对应于表面化学的显着变化。由于不同的羟基化程度和化学吸附CO和CO 2的能力不同,表面化学对电化学性能的影响随Y含量的变化而变化很大。
更新日期:2016-09-26
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