A Study of the Optimal Conditions for the Development of Preferred Oriented Platinum Surfaces by Means of Fast Square Wave Potential Perturbations

Changes in the vol tammetr ic response of polycrystal l ine p la t inum in the direct ion expected for preferred oriented surface electrodes are achieved after applying a fast repetitive square wave potential signal covering the potential range of Hand O-electroadsorption/electrodesorption. The influence of the characteristics of the square wave potential signal on the voltammetric response of the modified platinum surfaces is systematically studied to establish the optimal conditions for obtaining surface structures with determined preferred orientations. Recent ly , it was found that changes in the vol tammet r ic response of polycrys ta l l ine p la t inum e lec t rodes in the d i rec t ion expec ted for p re fe r red or ien ted surface e lec t rodes can be ach ieved by us ing a fast repe t i t ive square wave potential signal (RSWPS) within the potential range of Hand O-e lec t roadsorp t ion /e lec t rodesorpt ion in acid solut ion (1). Similar resul ts were earl ier obta ined by applying a fast t r iangular potential signal to a polycrysta l l ine p la t inum electrode in acid e lect rolyte at room tempera ture (2, 3). After applying the fast potential pe r tu rba t ion the e lec t roae surface modif icat ions were vo l tammet r ica l ly fol lowed at a low potent ia l sweep rate in the Hand O-elec t roadsorpt ion/e lec t rodesorpt ion potential range by using an acid electrolyte. These changes in the e lec t rode surface can also be seen th rough SEM for a re la t ive ly low magnif ica t ion factor (4). The change f rom the init ial po lycrys ta l l ine p la t inum surface to the preferred oriented surface is independent of the shape of the per iodic potent ia l per turba t ion , but it is ex t r eme ly sens i t ive to its f r equency and potent ia l l imits (1, 2, 5). Thus, depending on the preset parameters of the potential per turbat ion ei ther the pla t inum (100) preferred orien ted surface or the p la t inum (111) prefer red or ien ted surface are obtained (1-5). In the present work the influence of the RSWPS characterist ics on the vol tammetr ic response at low potential sweep rate of the resul t ing p la t inum surfaces is sys temat ica l ly s tud ied to es tabl ish the opt imal condit ions for obtaining surface structures with a de termined preferred orientation.