Investigation of the surface topography and double layer characteristics of variously pre-treated antimony single crystal electrodes

Abstract

The geometrical roughness factor, root mean square departure of the surface from flatness, the medium lateral correlation length and other parameters have been obtained for variously pre-treated Sb(1 1 1) and Sb(0 0 1) electrodes. Atomic resolution was achieved for cleaved at liquid nitrogen temperature Sb(1 1 1) surface using UHV-STM method. The surface pits with various depths and widths on the surface of electrochemically and chemically etched Sb(1 1 1) electrodes, and deep furrows on the surface of cleaved Sb(0 0 1) have been observed. Electrical double layer characteristics of variously pre-treated Sb(1 1 1) and Sb(0 0 1) electrodes were studied in terms of the Debye length dependent roughness theory (i.e., non-linear Poisson–Boltzmann theory), recently developed by Daikhin et al. [Phys, Rev. E 53 (1996) 6192; Electrochim. Acta 42 (1997) 2853 and J. Chem. Phys. 108 (1998) 1715]. According to the experimental data and results of theoretical calculation, the surface roughness increases in the order of Sb electrodes: cleaved at the temperature of liquid nitrogen Sb(1 1 1) < electrochemically polished single crystal Sb(1 1 1) < electrochemically etched Sb(1 1 1) < chemically etched Sb(1 1 1) < cleaved at temperature of liquid nitrogen Sb(0 0 1). This order of the electrode surface roughness is in agreement with the data obtained from STM, AFM and impedance measurements.