In this talk we present the first reported photothermal infrard (PTIR) spectra of ultrathin bilayer silicate films with a spatial resolution better than 10nm and compare this with traditional infrared reflection absorption spectroscopy (IRRAS) of the same surface. The growth of ultrathin bilayer silicates on Pd(100) and Pd(111) is demonstrated under a variety of conditions and was observed in real-time with an in-situ low energy electron microscope (LEEM) and micro-low energy electron diffraction (μ-LEED). The bare Pd(100) and Pd(111) surfaces are fluid-like at the crystallization temperature of the silicate film as evidenced by the movement of the steps and terraces on the Pd surfaces. After crystallization of the silicate films was observed with LEEM and μ-LEED, the samples were further characterized with X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), IRRAS and PTIR. The resolution of the infrared peaks from the nanoIR instrument are substantially better than those obtained from the traditional IRRAS setup owing to the significantly smaller sampling area. The PTIR spectra are overlayed with the topographic information obtained from the AFM tip and some hyperspectral images will be presented. The chemical activity and selectivity of these model silicate/Pd catalysts will also be discussed.

Spectromicroscopy of ultrathin bilayer silicate films on Pd(100) and Pd(111)

2019 Spring National Meeting

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