Electrosynthesis of formic acid and hydrogen via efficient glycerol oxidation on a 2-methylimidazole-modified NiCo LDH

Abstract

The electrocatalytic glycerol oxidation reaction (GOR) coupled with the hydrogen evolution reaction (HER) presents an innovative strategy for the co-production of value-added chemicals and green hydrogen. However, its efficiency is often hindered by the sluggish kinetics of conventional layered metal catalysts. Herein, we report a nickel-cobalt layered double hydroxide (NiCo LDH) electrocatalyst synthesized via a 2-methylimidazole-modified strategy, which significantly enhances GOR performance. The optimized catalyst exhibits a low potential of 1.44 V vs. RHE to deliver 100 mA cm⁻² and achieves a high Faradaic efficiency of 93.7% for formic acid. When integrated into a two-electrode GOR||HER system, the catalyst enables stable operation at 300 mA cm⁻² with a hydrogen Faradaic efficiency of 96.5%. Both experimental and mechanistic studies demonstrate that 2-methylimidazole not only directs the formation of a well-defined layered architecture but also modulates the surface chemistry by increasing oxygen content and optimizing Ni–Co electronic synergy, which collectively enhance the adsorption of active oxygen intermediates and boost GOR performance. This work provides a rational ligand-mediated approach for designing high-performance layered electrocatalysts toward the efficient glycerol valorization and hydrogen production.