Construction of Cu3+-OH-Pt Interface for Enhancing Glycerol Electrooxidation Coupled with Hydrogen Evolution

The electrochemical conversion of glycerol-a biodiesel byproduct into formic acid coupled with hydrogen evolution reaction (HER) offers a green route for biomass utilization. However, existing systems suffer from high energy demands and insufficient selectivity. Herein, a self-grown copper oxide nanorods decorated with platinum species (Pt/CuO NRs) is developed, reaching a current density of 20 mA cm-2 at 1.14 V vs. RHE, with 97.4% formic acid selectivity at 1.40 V vs. RHE and nearly 100% glycerol conversion. Electrochemical impedance spectroscopy and in situ Raman spectroscopy reveal that Pt0 sites enhance electron transfer at the Cu3+-OH-Pt interface, facilitating CuⅢ-OOH formation. Density functional theory (DFT) analysis shows that Pt weakens O-H bond strength in CuOOH and lowers the dehydrogenation energy barrier, synergistically boosting GOR. Furthermore, a membrane electrode assembly (MEA) with Pt/CuO NRs as the anode and Pt/CuOx (c-Pt/CuOx) as the cathode is established for GOR and HER, respectively, which can operate at 1.55 V for a current density of 100 mA cm-2, reducing the potential by 380 mV compared to water splitting. The developed GOR(+)||HER(-) electrolyzer demonstrates stable performance for 100 hours at 150 mA cm-2, with a formic acid selectivity of 90%. This represents a significant improvement over existing copper-based catalysts, highlighting the green chemistry advantages. The techno-economic analysis demonstrated the economic viability of electrochemically converting glycerol into potassium dicarboxylate (KDF) and H₂, with processing costs of $4655-4797 per ton and a market value of $6389 per ton at representative commercial current densities of 100 and 300 mA cm-2.