The effect of chemical surface oxidation of the carbon black Vulcan XC-72R on the capacitance, tolerance to corrosion and electrochemical activity toward the hydrogen evolution reaction (HER) has been studied in 0.1 M NaHCO3. Acid treatments with HNO3 or a HNO3-H2SO4 mixture resulted in a progressive introduction of oxygen-containing groups which led to a strong increase of the capacitance and a higher tendency to carbon corrosion. In contrast, an inhibition of the hydrogen evolution current (at potentials more negative than -1.0 V) was observed for oxidized samples in comparison to the un-treated material. HER was also tested in the presence of dissolved CO2 to study the influence of the surface chemistry on the CO2 electroreduction. An inhibition of the H-2 evolution current was evidenced in the CO2 saturated electrolyte due to the adsorption of species from CO2 reduction. A strong hydrogen current decrease (65-78%), and thus a higher tendency to adsorb (CO2)(red) species, was obtained on the original Vulcan and the HNO3-treated samples, in comparison to the carbon oxidized with HNO3-H2SO4 (15%), which could be related to the highest content of basic groups of the last carbon. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.