Electrocatalytic Oxidation of Lignin on Cobalt Electrodes in Alkaline Media

In the context of the global energy transition, the utilization of renewable feedstocks is imperative. The Lignin Electrochemical Oxidation Reaction (LEOR) represents a promising route to valorize biomass residue from industrial processes into high-value aromatics, such as vanillin, while simultaneously generating green hydrogen. While nickel is extensively studied for the LEOR, cobalt remains relatively unexplored. In this work, we optimized a potentiostatic electrodeposition process to fabricate cobalt electrodes with a high-surface-area petal-like morphology (approximately 5.8 × 1019 active sites per cm2geom). The Co electrocatalyst exhibited a high Faradaic efficiency for vanillin (19.5%)─surpassing bulk Ni electrodes─with high product selectivity. Remarkably, this performance was achieved at an overpotential 400 mV lower than that of nickel. However, stability challenges remain as the electrode underwent morphological degradation and surface area loss during operation.