Single-pass electrooxidation of glycerol on bismuth-modified platinum electrodes as an anodic process coupled to the continuous CO2 electroreduction toward formate

Abstract

CO₂ electroreduction has emerged as a promising strategy for reducing emissions while simultaneously generating valuable products, particularly formic acid/formate. To further enhance the sustainability of this process, the traditional oxygen evolution reaction at the anode can be replaced by a more interesting reaction like glycerol oxidation to high value-added products, in a covalorization approach. In this study, the effect of the presence of a bismuth (Bi) atom supplier (Bi₂O₃ particles) in the anolyte solution during the glycerol electrooxidation process on platinum (Pt) electrodes coupled with the electroreduction of CO₂ to formate is investigated for the first time, operating in a continuous mode with a single pass through the reactor. The results reveal that in the cathode, significant HCOO− production, with Faradaic efficiencies reaching 93%, and modest energy consumption of 208 kW h·kmol−¹ were obtained in the continuous CO2 electroreduction to formate using Bi gas diffusion electrodes. On the other hand, in the anode, the presence of Bi₂O₃ particles leads to a significant alteration in the distribution of high-value-added oxidation products obtained. For instance, the anode demonstrates remarkable dihydroxyacetone (DHA) production of 283 μmol·m−² ·s −¹ , surpassing the results obtained with the nonmodified Pt electrodes. The performance of this system offers a promising pathway for the simultaneous coproduction of high-value-added products from both CO₂ and glycerol.