(220c) Understanding Amorphous Silica Coatings on the Platinum Surface with First Principles Calculations

Semi-permeable silica membranes are attractive as protective coatings for electrocatalysts, both for blocking contaminants from poisoning the catalyst and for preventing the aggregation of supported catalyst nanoparticles. Such coatings are not passive bystanders but can also affect the catalytic properties. However, to utilize the interplay of coating and catalyst, a better understanding of the coating/catalyst interface on the atomic scale is needed.

Here, we apply first principles calculations and ab initio molecular dynamics simulations to investigate how amorphous silica interacts with the surface of platinum metal electrocatalysts. Using a crystalline model interface structure, we compare different interface terminations and establish which bonds are formed between the SiO₂ membrane and the Pt(111) surface in aqueous electrolytes. We discuss how the dynamic nature of the interface may affect the catalytic properties of the SiO₂/Pt system.

The SiO₂/Pt system can be considered a simple model system for oxide-coated electrodes, and our approach can be readily extended to oxide coatings in other electrochemical devices such as batteries.