ANION ADSORPTION ON PT(100) FROM SULFURIC-ACID - ELECTROCHEMISTRY ANDFOURIER-TRANSFORM INFRARED-SPECTROSCOPY

The adsorption of bisulfate and sulfate anions from 0.05M H2SO4 soluti on on Pt(100) was characterized by Fourier transform infrared spectros copy (FTIR). Subtractively normalized interfacial FTIR spectra (SNIFTI RS) indicated only weak adsorption of bisulfate at potentials below 0. 4 V (vs. PdH), in contrast to the strong adsorption seen on the (111) surface by the same technique. At potentials above 0.6 V the SNIFTIRS spectra were due entirely to diffuse layer species. At potentials betw een 0.4 and 0.6 V, changes in the IR bands indicated either a rearrang ement (and possibly deprotonation) of adsorbed bisulfate or weak adsor ption of sulfate ion.