Determination of the potentials of zero total charge of Pt(100) stepped surfaces in the [011̄] zone. Effect of the step density and anion adsorption

The electrochemical behavior of Pt(S)[n(100)×(111)] electrodes is examined in perchloric acid solutions in the absence and in the presence of sodium acetate. Charge densities associated with adsorption processes at step and terrace sites have been analyzed as a function of the step density. The results obtained from CO displacement experiments allow the estimation of, in a first approximation, the corresponding potentials of zero total charge (pztc). The values of the pztc diminish with the step density. In the case of acetate containing solution, the specific adsorption of acetate anions was monitored by means of Fourier transform infrared (FTIR) spectroscopy. The potential and the step density dependence of the corresponding infrared adsorption bands have been found to be in agreement with the electrochemical results.