Temperature-programmed desorption mass spectrometric study of the surface properties of glassy carbon

Abstract

The temperature-programmed desorption (TPD) method combined with mass spectrometric analysis has been applied to the characterization of glassy carbon (GC) and modified glassy carbon surfaces. Five different samples of GC were obtained from a commercial resol type of phenol formaldehyde resin that bad undergone several treatments: the samples were either pure GC, GC treated with boron and phosphorus, or GC modified by metal (silver and palladium). Mass spectrometric analysis has shown that the thermal decomposition of surface oxide species results in desorption of H2O, CO and CO2, these being the major gas products. On the basis of the TPD spectra obtained, desorption energies have been calculated using a peak position method. The influence of CO2 oxidation on the surface properties of the samples was also investigated. It was concluded that metal deposition on a glassy carbon surface contributes to increased stability of surface oxide species, the most stable surface being one that has been modified by palladium deposition.