Kinetics of dissociative adsorption of formic acid on electrodes of tetrahexahedral platinum nanocrystals

Abstract

In the present paper we study the kinetics of dissociative adsorption of formic acid on the electrode of tetrahexahedral platinum nanocrystals (THH Pt NCs). In situ FTIR spectroscopic results demonstrate that HCOOH can be oxidized to CO2 at a low potential (−0.2 V(SCE)) on the THH Pt NCs electrode, and the chemical bonds inside formic acid molecule are broken to form adsorbed COL species. The kinetics of the dissociative adsorption of HCOOH was quantitatively investigated by employing programmed potential step technique. It has been determined that, in 5 × 10−3 mol·L−1 HCOOH + 0.1 mol·L−1 H2SO4 solution, the maximal value of the average rate (υ a max ) of dissociative adsorption of HCOOH on a commercial Pt/C catalyst electrode is 8.58 × 10−10 mol·cm−2·s−1, while on the THH Pt NCs the υ a max is 1.5 times larger than the υ a max measured on Pt/C and reaches 13.19 × 10−10 mol·cm−2·s−1. The results have revealed that the reactivity of the THH Pt NCs is much higher than that of the Pt/C catalysts.