We have recently shown that acid washing of a carbon support prior to metal (Au, Pd) deposition enhances the activity of the resulting catalysts for the direct synthesis of hydrogen peroxide, a process with great industrial potential. Despite detailed characterisation of the treated carbon support using very high resolution STEM and XPS we have not been able to identify significant differences between the untreated and treated materials. We wish to build on recent, limited measurements made using TOSCA in order to compare and contrast the vibrational spectra from: untreated carbon, acid treated carbons which show enhancement (nitric acid and acetic acid), and two samples treated with hydrochloric acid and a base, ammonium hydroxide, where an adverse effect on activity is observed. Our key objective is to reveal the surface changes responsible for the catalytic enhancement.