Ligand‐Intercalated MOFs Enable Reaction‐Pathway Engineering in Biomass Electrooxidation via Steric and π‐Electronic Microenvironment Control

Abstract

ABSTRACT Controlling reaction pathways in electrocatalytic biomass upgrading remains challenging because mass transport, substrate adsorption, and elementary kinetics are intrinsically coupled within catalyst architectures. Here, we report a ligand‐intercalation strategy that enables selective reaction‐pathway engineering in layered metal–organic frameworks (MOFs) by decoupling effects of steric and electronic microenvironments. Aromatic dicarboxylate ligands with systematically varied length and π‐electron density are intercalated into NiCo‐based MOFs to create tunable interlayer nanochannels that independently regulate molecular diffusion and substrate–catalyst interactions. Expanded interlayer spacing enhances alcohol oxidation by improving mass transport and active‐site accessibility, whereas π‐electron‐rich ligands selectively promote aldehyde oxidation through strengthened π–π interactions and accelerated hydrogen atom transfer (HAT), resulting in a shift of the rate‐determining step (RDS) from a chemical to an electrochemical step. These orthogonal effects are quantitatively correlated with kinetic analysis, impedance spectroscopy, adsorption measurements, in situ spectroscopy, and density functional theory calculations. As a result, the optimized MOFs deliver low onset potentials, current densities up to 200 mA cm −2 , and near‐quantitative Faradaic efficiencies and product yields in the selective oxidation of representative biomass substrates, 5‐hydroxymethylfurfural and 2,5‐diformylfuran. This work establishes ligand‐intercalated MOFs as a versatile platform for microenvironment‐driven reaction‐pathway control in electrocatalytic biomass valorization.