Integrating Electrocatalytic 5-Hydroxymethylfurfural Oxidation and Hydrogen Production via Co–P-Derived Electrocatalysts

Electrocatalytic biomass valorization with renewable energy input represents a promising way to produce sustainable and nonfossil-based carbon products. Even more desirable is that the oxidative biomass upgrading can be integrated with H2 production in a single electrolyzer. Herein, we report that electrodeposited Co–P can act as competent electrocatalysts for 5-hydroxymethylfurfural (HMF) oxidation to 2,5-furandicarboxylic acid (FDCA) at the anode and H2 production at the cathode simultaneously in alkaline media. When serving as a catalyst precursor on the anode, Co–P was able to achieve a current density of 20 mA/cm2 for HMF oxidation in 1.0 M KOH with 50 mM HMF at 1.38 V vs RHE, prior to the takeoff of the competing reaction, O2 evolution. Long-term chronoamperometry demonstrated a nearly 100% conversation of HMF and a ∼90% yield of FDCA. When HMF oxidation and H2 evolution were integrated in one electrolyzer with a Co–P/Co–P catalyst couple, the potential required to achieve a current density of 20 mA/cm2 was 1.44 V, 150 mV lower than that of overall water splitting. Nearly unity Faradaic efficiency was obtained for H2 evolution. Overall, our results indicate that it is feasible to employ earth-abundant electrocatalyts to integrate H2 production and oxidative biomass upgrading with higher energy conversion efficiency than water splitting as well as to produce valuable products at both cathode and anode in a single electrolyzer.