Fabrication of Co-Decorated NiFe-LDH@NF Electrocatalysts for Efficient Catalysis of Glycerol Oxidation Reaction Coupled Water Electrolysis

The glycerol oxidation reaction (GOR) has emerged as a promising alternative to the oxygen evolution reaction in water electrolysis, owing to its lower thermodynamic oxidation potential (0.69 V vs. RHE) and the value-added nature of its oxidation products. In this work, cobalt species were electrodeposited onto a NiFe layered double hydroxide grown on nickel foam (Co/NiFe-LDH@NF), which was used as an efficient anode for the GOR. The catalyst is derived from a Ni/Fe-based electrode of the type already used in industrial alkaline water electrolysis through a simple electrochemical modification, without changing the electrode substrate or the cell configuration, and the approach is therefore compatible in principle with existing alkaline electrolysis systems. Structural and spectroscopic characterization shows that the sample retains a nanosheet-based architecture with a rougher, partially aggregated surface, and that cobalt is present as mixed-valence Co2+/Co3+ species decorated on the NiFe-LDH surface rather than as a separate crystalline phase. In a glycerol-containing alkaline electrolyte, the Co/NiFe-LDH@NF anode reaches 10 mA cm−2 at 1.271 V vs. RHE in a single measurement, which is 383 mV lower than the potential required by the oxygen evolution reaction (1.654 V vs. RHE) on the same electrode. In two separate chronoamperometric runs, glycerol-assisted water electrolysis produced formate at 0.234 mmol cm−2 h−1 with a Faradaic efficiency of ca. 97% and hydrogen at 32.47 mL cm−2 h−1 with a Faradaic efficiency of ca. 98%. During a 10 h stability test, the catalyst retained approximately 81% of its initial current in a single measurement; we report this as a moderate but measurable decay rather than as a demonstration of long-term durability. This study demonstrates a feasible strategy for designing integrated electrocatalytic systems that co-produce green hydrogen and valuable chemicals using earth-abundant materials, thereby improving both the energy efficiency and economic attractiveness of hydrogen production.