Activation Effect of Electrochemical Cycling on Gold Nanoparticles towards the Hydrogen Evolution Reaction in Sulfuric Acid

[Display omitted] This article reports a study of electrochemical cycling effects on hydrogen evolution catalytic activity of gold nanoparticles in sulfuric acid. We found that after cycling within the double layer regime, up to 0.64V vs RHE, there is a dramatic effect on the HER activity of gold nanoparticles: 128mV drop of the overpotential, a decrease of 23mV/dec for the Tafel slope as well as a nearly twenty times increase of the turn-over frequency (TOF). This enhanced activity is tentatively assigned to the formation of stepped like structures by the consecutive electrochemical cycling in the double layer region.