Acta Phys. -Chim. Sin. ›› 1998, Vol. 14 ›› Issue (10): 919-926.doi: 10.3866/PKU.WHXB19981011

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Kinetics of Irreversible Reactions on Platinum Single Crystal Electrodes(III)

Yang Yi-Yun, Sun Shi-Gang   

  1. Department of Chemistry,State Key Laboratory for Physical Chemistry of Solid Surfaces,Institute of Physical Chemistry,Xiamen University,Xiamen 361005
  • Received:1998-01-21 Revised:1998-05-11 Published:1998-10-15

Abstract:

Based on results of the lst and 2nd papers of the present studies, the procedure of data processing was developed further. Through the variation of the temperature of the reaction system the apparent Gibbs free energy of activation (△G≠0) for direct oxidation of HCOOH on Pt(100),Pt(111) and Pt(110) single crystal electrodes was obtained for the first time. Under the standard states defined in the present study i.e, at 0.0V/SCE.298.15K and 1.013×105Pa, the apparent Gibbs free energy of activatiou for HCOOH oxidation has been evaluated as 32.2±0.5 kJ.mol-1 on Pt(100), 25.8±0.4 kJ•mol-1 on Pt(111) and 10.1±0.2 kJ•mol-1 on Pt(110), respectively. It has been found that the transfer coefficient (β) of HCOOH oxidation is independent of temperature in the range between 283.15~303.15K, but varies with the surface atomic arrangement of Pt single crystal electrode and yields the same variation order as that of the apparent Gibbs free energy of activation.

Key words: Pt(100), Pt(111), Pt(110), Single erystal electrodes, Direct oxidation of HCOOH, Apparent Gibbs free energy of activation