Mechanism and kinetic study of pulse electrodeposition process of Pt/C catalysts for fuel cells.

The growth mechanism and the corresponding kinetic parameters are valuable to improve the electrodeposition method for preparing Pt-based catalysts. In this paper, the effect of the operation condition on the electrodeposition mechanism has been investigated through experiments and theoretical analysis, and the corresponding kinetic parameters were acquired. The catalytic activity of the deposited Pt catalyst prepared by the pulse current (PC) electrodeposition method was improved, compared with that of the commercial Pt catalyst and the Pt catalyst prepared by the direct current electrodeposition method. The results show that both high current density and high t on /t off in PC electrodeposition could cause large cathode overpotentials, resulting in faster nucleation rate and smaller catalyst particle size, which leads to the better reaction activity of the Pt catalyst. Finally, kinetic parameters including the constants, which relate the nucleation rate with the overpotential, the transfer coefficient and the exchange current density of the electrodeposition process, were determined. • Effect of deposition condition on the electrodeposition mechanism is revealed. • Kinetic parameters for the Pt-electrodeposition are acquired. • PC-deposited Pt shows higher catalytic activity than commercial and DC-deposited Pt. • Increasing applied current and t on / t off lead to small particle and better activity of Pt catalyst. [ABSTRACT FROM AUTHOR]