Ligand engineering tailors hydrophobic microenvironments for efficient electrocatalytic oxidation of fatty alcohol

The intrinsically low solubility of fatty alcohols in aqueous electrolytes imposes critical mass transport limitations for electrocatalytic oxidation. Conventional anodic electrocatalysts typically suffer from poor activity along with severe oxygen evolution reaction due to their hydrophilicity. Here, we present a ligand engineering strategy utilizing nickel-based metal-organic frameworks (Ni-MOFs) to construct hydrophobic microenvironments. Precise modulation of the aromatic structures of organic ligands promotes local enrichment of fatty alcohols and enhances structural robustness through π-π stacking interactions. Consequently, the optimized Ni-MOF exhibits enhanced activity for octanol oxidation compared to Ni(OH)2, achieving a threefold higher production rate and significantly improved Faradaic efficiency (84.7% versus 30.8%). The octanoic acid production rate is competitive with that of state-of-the-art thermocatalytic aerobic oxidation. This work highlights a general design principle for hydrophobic microenvironment to overcome mass transport barriers in organic electrocatalysis, demonstrating its potential for practical applications. Electrocatalytic oxidation of fatty alcohols in aqueous media is limited by mass transport due to their low solubility. Here, the authors propose ligand engineering to create hydrophobic microenvironments in Nickel MOFs, enabling efficient oxidation to fatty acids by enriching reactants.