Screening of Carbon-Supported Platinum Electrocatalysts Using Frumkin Adsorption Isotherms

Abstract

An important stage in the development of platinum electrocatalysts on carbon support is the analysis of their basic parameters. Cyclic voltammetry is an effective tool for analyzing the structural and electrochemical properties of such electrocatalysts. Using Frumkin adsorption isotherms, the contribution of the platinum surface to the hydrogen adsorption region was well described by three peaks corresponding to different crystal structures. The screening was carried out for platinum black and platinum electrocatalysts supported by carbon black, reduced graphene oxide (RGO), carbon nanotubes (CNTs), and nanofibers (CNFs). For most samples, the peak contribution to the electrochemical surface area (ESA) and corresponding hydrogen adsorption energies had close values, but the parameters deviated for Pt black and RGO-based samples was observed. The dependence of the calculated peak parameters on the number of accelerated stress test cycles was used to evaluate the effect of the type of carbon support on the stability of the electrocatalyst and the structure of platinum nanoparticles. The experimental results indicate a high degree of stability and differences in the degradation mechanisms of electrocatalysts based on nanostructured carbon compared to carbon black, which are explained by differences in the metal-support interaction and corrosion resistance of nanostructured carbon supports.

Keywords

• hydrogen adsorption
• cyclic voltammetry
• adsorption isotherm
• platinum electrocatalyst
• surface structure
• accelerated stress testing