The Effect of Acetone on the Kinetics of HER and UPD H Processes at a Pt(511) Single-Crystal Plane, Examined in a 0.5 M H2SO4 Solution

This work presents electrochemical examinations of acetone (at variable concentrations), including cyclic voltammetry, ac. impedance spectroscopy and Tafel polarization techniques, carried out on a Pt(511) single-crystal surface, with respect to the kinetics of the processes of underpotential deposition of hydrogen (UPD of H) and the hydrogen evolution reaction (HER), examined in 0.5 M H2SO4 solution. Essential conclusions of this work are related to acetone playing the role of the UPD H facilitator while exhibiting an overpotential-dependent, dual effect on the HER kinetics. Thus, acetone was found to be facilitating the HER rates at low overpotentials and deteriorating the HER kinetics at high overpotentials, driven by changes in the surface reaction mechanism. The above was evidenced through the recorded interfacial capacitance, charge-transfer resistance and Tafel parameters. By providing some important kinetic parameters, this article could be considered complementary to important works of other authors on acetone reactivity at Pt single-crystal electrode surfaces.