How do the unique Au/α-Fe2O3 interfacial structures determine activity in CO oxidation?†,Catalysis Science & Technology

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How do the unique Au/α-Fe2O3 interfacial structures determine activity in CO oxidation?†
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2018-10-04 00:00:00 , DOI: 10.1039/c8cy01467a
Lingli Gu _{1,

2,

3,

4,

5} , Qin Su _{1,

2,

3,

4,

5} , Wu Jiang _{1,

2,

3,

4,

5} , Yao Yao _{1,

2,

3,

4,

5} , Yijun Pang _{1,

2,

3,

4,

5} , Weijie Ji _{1,

2,

3,

4,

5} , Chak-Tong Au _{6,

7,

8,

9}

Affiliation

In this study, three α-Fe₂O₃ crystallites of regular morphology (truncated hexagonal bipyramid, quasi cubic, and hexagonal plate) were prepared in a controllable manner. Based on the (HR)TEM and SEM characterizations, the exposed crystal facets of three α-Fe₂O₃ crystallites, namely {113}, {214}, {104}, {110}, {012}, and {001}, were carefully identified. Au nanoparticles of ca. 2.0 nm with a narrow particle size distribution were essentially monodispersed on the three α-Fe₂O₃ substrates through a controlled deposition strategy. In such a way, the Au/α-Fe₂O₃ interfacial structures with structurally defined oxide substrates and nearly identical Au particle size and morphology have been obtained. The systems allowed us to compare in depth the behaviors of distinct surfaces/interfaces in CO oxidation. The characterization including O₂/surface hydroxyl-TPD, CO-TPSR, and in situ FTIR clarified the role of the surface oxygen/hydroxyl species in developing crucial intermediates on distinct interfaces. The results demonstrated that the evolution of different intermediates (CO₃²⁻ and HCO₂⁻) was directly controlled by interfacial features, i.e., the weakly adsorbed oxygen and surface hydroxyl species as well as the specific Au–Fe₂O₃ boundary structure, which meaningfully determined CO activation and conversion to CO₂. The present study provided new insights into the significance of Au/α-Fe₂O₃ interfacial structures governing the evolution of reaction intermediates in CO oxidation.

中文翻译：

如何独特的Au /的α-Fe _2层ö ₃界面结构确定在CO氧化活性？†

在这项研究中，三的α-Fe _2个ö ₃规则形态的微晶（截短的六方双锥，准立方和六方板）以可控的方式来制备。基于（HR）TEM和SEM表征，三个的露出晶面的α-Fe ₂ ö _3个微晶，即{113}，{214}，{104}，{110}，{012}，和{001} ，经过仔细识别。约金纳米粒子。具有窄的颗粒尺寸分布为2.0nm基本上单分散的三个的α-Fe _2个ö ₃通过受控沉积策略基材。以这样的方式，在Au /的α-Fe ₂ ö ₃已获得具有结构确定的氧化物底物和几乎相同的Au粒径和形态的界面结构。该系统使我们能够深入比较CO氧化过程中不同表面/界面的行为。包括O ₂ /表面羟基-TPD，CO-TPSR和原位FTIR的表征阐明了表面氧/羟基物质在不同界面上形成关键中间体方面的作用。结果表明，不同的中间体（CO演变₃^2-和HCO ₂^{- ）}中的溶液直接通过界面的功能，控制即，所述弱吸附氧和表面羟基物种以及特定的Au-的Fe ₂O ₃边界结构，有意义地决定了CO的活化和向CO _2的转化。本研究提供了新的见解的Au /α-Fe的意义₂ ö ₃理事反应中间体在氧化CO的演变界面结构。

更新日期：2018-10-04

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