Origin of the high selectivity of the Pt-Rh thin-film H2 gas sensor studied by operando ambient-pressure X-ray photoelectron spectroscopy at working conditions
Origin of the high selectivity of the Pt-Rh thin-film H2 gas sensor studied by operando ambient-pressure X-ray photoelectron spectroscopy at working conditions
复制标题
工作条件下操作环境压力X射线光电子能谱研究Pt-Rh薄膜H2气体传感器高选择性的起源
DOI：
10.1021/acs.jpclett.2c02365
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Hiroshi Kondoh
中科院分区：
文献类型：
--
作者：
Ryo Toyoshima;Takahisa Tanaka;Taro Kato;Ken Uchida;Hiroshi Kondoh
Pt-Rh薄膜传感器对H2gas检测具有良好的灵敏度和选择性。在此，我们研究了Pt-Rh薄膜传感器在工作条件下与电阻率测量并行进行环境压力x射线光电子能谱（AP-XPS）测量的高选择性检测h2o2的机理。表面Pt和Rh的元素组成和化学状态随着背景气体环境的变化而急剧变化，这直接关系到传感器的响应。结果表明，表面分离的Pt原子加速H2的解离吸附，导致传感器表面的还原，从而降低薄膜的电阻率，而薄氧化的Rh层则阻止了另一种还原剂NH3的解离。由密度泛函理论（DFT）计算得到的吸附能量支持了这一点。
The Pt–Rh thin-film sensors exhibit excellent sensitivity and selectivity for H2gas detection. Here, we studied the mechanism of highly selective detection of H2by the Pt–Rh thin-film sensors with ambient-pressure X-ray photoelectron spectroscopy (AP–XPS) measurements at working conditions, which were paralleled with electric resistivity measurements. The elemental composition and chemical state of surface Pt and Rh drastically change depending on the background gas environments, which directly link to the sensor response. It is revealed that surface segregated Pt atoms accelerate dissociative adsorption of H2, resulting in a reduction of the sensor surface and then a decrease of electric resistivity of the film, whereas a thin oxidized Rh layer blocks dissociation of the other reducing agent, that is, NH3. This is supported from the adsorption energetics obtained by the density functional theory (DFT) calculations.