Atomic Structure Control of Silica Thin Films on Pt(111)

Abstract

Metal oxide thin films grown on metal single crystals are commonly used to model heterogeneous catalyst supports. The structure and properties of thin silicon dioxide films grown on metal single crystals have only recently been thoroughly characterized and their spectral properties well established. We report the successful growth of a threedimensional, vitreous silicon dioxide thin film on the Pt(111) surface and reproduce the closed bilayer structure previously reported. The confirmation of the three dimensional nature of the film is unequivocally shown by the infrared absorption band at 1252 cm −1 .Temperature programmed desorption was used to show that this three-dimensional thin film covers the Pt(111) surface to such an extent that its application as a catalyst support for clusters/nanoparticles is possible. The growth of a three-dimensional film was seen to be directly correlated with the amount of oxygen present on the surface after the silicon evaporation process. This excess of oxygen is tentatively attributed to atomic oxygen being generated in the evaporator. The identification of atomic oxygen as a necessary building block for the formation of a three-dimensional thin film opens up new possibilities for thin film growth on metal supports, whereby simply changing the type of oxygen enables thin films with different atomic structures to be synthesized. This is a novel approach to tune the synthesis parameters of thin films to grow a specific structure and expands the options for modeling common amorphous silica supports under ultra high vacuum conditions.

Controlling Ethylene Hydrogenation Reactivity on Pt13 Clusters by Varying the Stoichiometry of the Amorphous Silica Support

“…A UHV chamber equipped with a laser vaporization cluster source was used to synthesize three different a‐SiO 2 thin films on a Pt(111) single crystal using the procedure detailed in our previous publication . These films (which are 4–5 layers thick) are: silicon‐rich, stoichiometric, and oxygen‐rich.…”

“…AU HV chamber equipped with al aser vaporization cluster source [32] was used to synthesize three different a-SiO 2 thin films on aP t(111) single crystal using the procedure detailed in our previous publication. [33] These films (which are 4-5 layers thick) are:silicon-rich, stoichiometric, and oxygenrich. Complete experimental details of the film growth, characterization, cluster deposition, and activity measurements can be found in the Supporting Information.…”

A Two-Dimensional ‘Zigzag’ Silica Polymorph on a Metal Support

“…Ultrathin silica films have been grown on a number of metal single crystals and have become a research topic of their own. − Depending on the oxygen affinity of the metal substrate, either single layers directly bound to the metal substrate or bilayer films only van der Waals bound to the substrate, or both on the same substrate, have been prepared. Especially bilayer films were thoroughly studied with a particular emphasis on the analysis of crystalline and amorphous structures.…”

Electronic Band Structure of Ultimately Thin Silicon Oxide on Ru(0001)

“…Recently, metal-supported crystalline silicon oxide films have been grown as thin as mono- and bilayers. − The silicon oxide structure can be described as a network of corner-sharing SiO 4 tetrahedra forming a honeycomb lattice. This ultimately thin silicate, also called 2D silicon oxide, has particularly interesting properties.…”