ABSTRACT The electrochemical valorization of glycerol (GLY), a major byproduct of biodiesel production, into high‐value lactic acid (LA) under ambient conditions presents a sustainable pathway for biomass utilization. This study reports a facile 2‐step electrodeposition strategy to construct Au‐FeO x ‐NF heterostructured electrocatalysts on nickel foam (NF) substrates for selective GLY oxidation. Comprehensive characterization via scanning electron microscopy (SEM), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS) confirms that FeO x modification electronically modulates Au active sites, optimizing catalytic performance. In 3 M KOH electrolyte at an optimal potential of 0.1 V versus Ag/AgCl, the catalyst achieves a current density of 310 mA·cm −2 with exceptional LA selectivity of 74.3% (the maximum can reach 78.11% at 0 V vs. Ag/AgCl) and a production rate of 12.58 mmol·L −1 h −1 , representing a nearly fourfold enhancement over pristine Au‐NF. The catalyst demonstrates outstanding durability, maintaining > 70% LA selectivity across five consecutive cycles and throughout 10‐h continuous electrolysis. Mechanistic investigations reveal that the FeO x promoter layer synergistically enhances selective adsorption of GLY via its secondary hydroxyl group while accelerating the generation of active hydroxyl radicals (·OH). This dual‐function mechanism facilitates GLY oxidation to dihydroxyacetone (DHA) as the key intermediate, which subsequently undergoes base‐catalyzed rearrangement to LA. This work establishes an effective strategy for the sustainable upgrading of biodiesel‐derived waste into valuable platform chemicals, offering promising implications for integrated biorefinery applications and circular economy initiatives.
Liu et al. (Sat,) studied this question.