Dissolution and surface area loss of platinum nanoparticles under potential cycling

The relationship between dissolution and loss of the electrochemically active surface area (ECA) of Pt nanoparticles under potential cycling was investigated in a 0.5 M H2SO4 solution at 298 K. The nanoparticles were prepared on an Au electrode by electrodeposition in a 40 mM H2PtCl6 solution. Potential cycling was performed for 300 cycles in two different potential ranges: 0.0–1.0 V and 0.0–1.4 V. In both the potential ranges, ECA exhibited rapid loss during the first 100 cycles, but there were no significant changes in Pt dissolution. Pt dissolution was significantly enhanced by shifting the upper potential limit from 1.0 to 1.4 V, but ECA was not affected. On the basis of this result, it is expected that ECA loss was mainly due to agglomeration of Pt rather than electrochemical Ostwald ripening.

► Potential cycling tests of Pt were carried out in 0.5 M H2SO4 solution at 298 K.
► Electrochemical active surface area of Pt decreased gradually during the cycling.
► Pt dissolution decreased a little with the number of cycles.
► All results indicated Pt dissolution was independent of the surface area loss.
► Pt particle coarsening was assumed to be due to an agglomeration in this study.