Glycerol Electrooxidation on Platinum-Tin Electrodeposited Films: Inducing Changes in Surface Composition by Cyclic Voltammetry

GISELE A. B. MELLO; PABLO S. FERNÁNDEZ; MARÍA E. MARTINS; GIUSEPPE A. CAMARA

Electrocatalysis

SPRINGER

Año: 2017 vol. 2017 p. 1 - 10

1868-2529

In this work, PtSn binary electrodeposits wereprepared in three compositions and submitted to successivevoltammetric cycles in presence of glycerol (1.0 mol L−1) inacidic media. Catalysts were characterized by energydispersive X-ray analysis and X-ray photoelectronspectroscopy before and after the cycles being performed, inorder to check eventual changes in their compositions duringthe process. Spectroscopic results show that surface compositionsare sensibly richer in Sn than their bulk counterparts.Overall, PtSn catalysts show a poor initial catalytic activitytoward glycerol electrooxidation. However, as the cyclessucceed, the voltammetric responses increasingly resemblethat of Pt, while the oxidation currents increase. Results arerationalized in terms of a continuous enrichment of the surfaceby Pt at the expenses of a loss of Sn. Moreover, when theelectrochemical surface area (ECSA) is estimated by strippingof CO, it becomes evident that electrooxidation currentsremain growing, even when the ECSA is decreased, whichmakes the gain in catalytic activity particularly relevant.Ultimately, from a broader perspective, our results suggest thatcatalytic surfaces with tunable features (such as surfacecomposition and catalytic response) can be obtained by theapplication of easily executable electrochemical protocols.