Understanding hydrogen evolution reaction in bicarbonate buffer

• Bicarbonate reduction is an important pathway for hydrogen evolution on gold and platinum electrodes. The rate of bicarbonate strongly dependent mass transport. cations, in different ways gold. most likely a direct pathway, not mediated by solution acid-base reaction. Buffers are often employed as electrolytes their ability to resist pH changes. Still, they just spectators the electrocatalytic processes, rather may take primary role. Here, we attempt understand mechanism reaction (HER) bicarbonate-containing two distinct materials, Au Pt. Keeping bulk constant, voltammetric measurements reveal promotional effect HER presence buffer, well substantial change with Tafel Slope resembling one acidic media (ca. 100 40 mVdec ?1 Pt, respectively). Nevertheless, because increase surface due concomitant water (2H 2 O + 2e ? ? H OH ), consumed reactions branch becomes significant only large buffer concentrations. appear intrinsically different, exhibit opposite dependence cation identity scale differently specific area electrode. Through microkinetic modelling, exclude that can be explained via generation proton reactions. Rather, suggest which, negatively charged reactant, concentration.