Electrochemical oxidation of guaiacol as a sacrificial anodic process producing fine chemical derivative, for hydrogen production via electrolysis

In this paper we propose an alternative strategy to produce green hydrogen in a more sustainable way than standard water electrolysis, where a substantial amount of the electrical energy is wasted in the oxygen evolution quite often simply released in the atmosphere. The HER (hydrogen evolution reaction) is effectively coupled with the oxidation of guaiacol at the anode, leading to the simultaneous production of H 2 and valuable guaiacol oligomers. Significative points i) a substantial decrease of the potential difference for the HER, 0.85 V with guaiacol ii) HER is accompanied by the production of industrially appealing and sustainable guaiacol based oligomers iii) guaiacol oxidation runs efficiently on carbon-based surfaces like graphite and glassy carbon, which are cheap and not-strategic materials. Then, the electrochemical oxidation mechanism of guaiacol is studied in detail with in-situ EPR measurements and post-electrolysis product characterization: LC-DAD, LC-MS and NMR. Experimental results and theoretical calculations suggest that guaiacol polymerization follows a Kane-Maguire mechanism. • Hydrogen production via electrolysis is coupled to the sacrificial oxidation of guaiacol, yielding fine chemical products. •H 2 gas evolution coupled to guaiacol sacrificial oxidation takes place at 0.85 V, 31 % less than 1.23 V water splitting. •Evolved H 2 gas volume is measured in relation to the guaiacol sacrificial oxidation, featuring 75.5 % Faradaic Efficiency. •Oligo-guaiacol products are characterized via chromatography, EPR and NMR measurements.