GOALI: STM and AXAFS Studies of Electronic Effects due to Metal Support Interaction on Noble Metal Supported Catalysts

这是一个GOALI校企合作项目。沃尔夫教授和米勒博士将测量贵金属催化剂在不同载体上的电子特性，并验证这些特性的变化是否与观察到的转换频率和选择性的数量级变化相关。模型催化剂将由沉积在金属氧化物支撑（氧化铝、二氧化硅、二氧化钛和k掺杂氧化铝，沉积或生长在Mo（110）上）薄膜上的Pt和Pd组成。将其与标准高表面催化剂进行比较。利用扫描隧道光谱（STS）探测表面表面的电子结构；扫描显微镜观察其形貌；研究了其与新戊烷氢解和甲烷氧化的反应动力学。将合成不同尺寸的金属颗粒。STM将用于确定颗粒尺寸分布，STS将通过裸支架和颗粒涂层催化剂上的I-V曲线获得电子特性。漫反射红外光谱（DRIFTS）吸附CO将得到结构和电子性质的信息。用EXAFS测定金属和支架的近邻结构。Pt的原子间电位将用原子吸收x射线光谱（AXAFS）测定，并与催化和DRIFTS结果相关联。酸度测定将涉及氨化学吸附。STM工作将在圣母大学进行，而BP Amoco公司的EXAFS工作将需要阿贡国家实验室的资源。

This is a GOALI university-industry collabortive project. Prof. Wolf and Dr. Miller will measure the electronic properties of noble metal catalysts on various supports and verify whether changes in those properties are correlated with the observed changes by orders of magnitude in turnover frequency and selectivity. The model catalysts will consist of Pt and Pd deposited on thin films of metal oxide supports (alumina, silica, titania, and K-doped alumina, deposited or grown on Mo (110)). They will be compared with standard high surface are catalysts. The electronic structure of surfaces of surfaces will be probed with scanning tunneling spectroscopy (STS); its morphology with scanning microscopy (STM); and its reactivity with the kinetics of hydrogenolysis of neopentane and oxidation of methane. Metal particles will be synthesized with different sizes. STM will be used to ascertain the particle size distribution and STS will yield the electronics characteristics via I-V curves on the bare support and the particle-coated catalyst. Diffuse reflectance infrared spectroscopy (DRIFTS) of adsorbed CO will yield structural and electronic property information. The near neighbor structure of metals and support will be determined with EXAFS. The interatomic potential of Pt will be determined with atomic absorption x-ray spectroscopy (AXAFS) and correlated with catalysis and DRIFTS results. Acidity determinations will involve ammonia chemisorption. The STM work will be carried out at Notre Dame, while the EXAFS work by BP Amoco will require resources of the Argonne National Laboratory.