Electrifying Oxide Model Catalysis: Complex Electrodes Based on Atomically-Defined Oxide Films
Electrifying Oxide Model Catalysis: Complex Electrodes Based on Atomically-Defined Oxide Films
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DOI：
10.1007/s10562-019-03078-x
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发表时间：
2020-06-01
影响因子：
2.8
通讯作者：
Libuda, Joerg
中科院分区：
文献类型：
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作者：
Brummel, Olaf;Libuda, Joerg
通过研究基于明确定义的氧化物表面的复杂模型催化剂，已经获得了对许多多相催化过程的表面化学的基本见解。在这一视角下，我们总结了一系列的研究，其中我们将这种模型催化方法转移到了电催化领域。我们的模型电催化剂由生长在原子定义的氧化膜上的铂纳米颗粒(NPs)组成。具体地说，我们在Ir(100)载体上使用了有序的Co3O4(111)薄膜。采用物理气相沉积(PVD)法制备了铂纳米粒子，其粒径从几个纳米到亚纳米范围内变化。我们使用专用的制备系统在超高真空(UHV)条件下制备了所有模型催化剂。这种装置使我们能够将模型催化剂从超高压转移到电化学环境中，以应用各种原位技术，而不需要暴露在空气中。我们用在线电感耦合等离子体质谱(ICPMS)、电化学红外反射吸收光谱(EC-IRRAS)、扫描隧道显微镜(STM)、非原位再现X射线光电子能谱(XPS)和低能电子衍射(LEED)研究了原始Co3O4(111)和铂/Co3O4(111)的稳定窗口。在稳定窗口(pH 10，0.3-1.1V-RHE)内，模型电催化剂的表面结构保持不变。我们在超高压和电化学环境中对相同的样品进行了分析。具体地，我们用同步辐射光电子能谱(SR-PES)和非原位重现XPS分析了电子结构，用红外反射吸收光谱(IRAS)、程序升温脱附(TPD)、EC-IRRAS和循环伏安(CV)研究了CO的吸附和氧化。模型电催化剂表现出明显的颗粒大小效应，金属载体相互作用对其催化活性起着关键作用。尤其重要的是界面铂氧化物，它由氧化物载体稳定存在，存在于低至0.5V-RHE的电极电位下。此外，溢出效应使新的反应机制成为可能，其中包括来自氧化物载体的氧。这篇综述展示了模型电催化方法的潜力，为基于复合氧化物的电催化提供了基本的见解。图解
By studying complex model catalysts based on well-defined oxide surfaces, fundamental insights have been obtained into the surface chemistry of many heterogeneously catalyzed processes. In this perspective, we summarize a series of studies, in which we have transferred this model catalysis approach to the field of electrocatalysis. Our model electrocatalysts consisted of Pt nanoparticles (NPs) grown on atomically-defined oxide films. Specifically, we used well-ordered Co3O4(111) thin films on an Ir(100) support. The Pt NPs were prepared by physical vapor deposition (PVD) and the particle size was varied from a few nanometers to the sub-nanometer size range. We prepared all model catalysts under ultra-high vacuum (UHV) conditions using a dedicated preparation system. This setup enables us to transfer the model catalysts from UHV into the electrochemical environment to apply various in-situ techniques without exposure to air. We investigated the stability window of pristine Co3O4(111) and Pt/Co3O4(111) using online inductively coupled plasma mass spectrometry (ICPMS), electrochemical infrared reflection absorption spectroscopy (EC-IRRAS), scanning tunneling microscopy (STM), ex-situ emersion X-ray photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED). Within the stability window (pH 10, 0.3-1.1 V-RHE) the surface structure of the model electrocatalysts is preserved. We analyzed identical samples both in UHV and in the electrochemical environment. Specifically, we applied synchrotron radiation photoelectron spectroscopy (SR-PES) and ex-situ emersion XPS to analyze the electronic structure and we used infrared reflection absorption spectroscopy (IRAS), temperature programmed desorption (TPD), EC-IRRAS, and cyclic voltammetry (CV) to study CO adsorption and oxidation. The model electrocatalysts show pronounced particle size effects and metal support interactions are shown to play a key role in their catalytic reactivity. Of particular importance is an interfacial Pt oxide, which is stabilized by the oxide support and exists at electrode potentials as low as 0.5 V-RHE. Moreover, spillover effects enable new reaction mechanisms, which involve oxygen from the oxide support. This review demonstrates the potential of the model electrocatalysis approach to provide fundamental insights into complex oxide-based electrocatalysis. Graphic