The effect of organic molecules adsorption on hydrogen absorption in relation to the hydrogen evolution reaction

Abstract

The competitive adsorption of organic molecules (2, 7-naphthalenedisulfonic acid) and adsorbed H is of interest in relation to its influence on H absorption into a Pd-Ni electro-deposited alloy. The experimental results, in acid solution, show an enhancement of the coverage of the electrode surface with adosrbed H due to the competitive adsorption of organic molecules that interfere with H atoms, through lateral attractive interactions between the adsorbed species and communal electronic effects, leading supposedly to a decreased probability of H entry into the alloy. Chemisorbed H is, on the other hand, an intermediate in the HER, so the enhancement of the electrode coverage in the presence of co-adsorbed organic molecules promotes the hydrogen evolution reaction.