Field-Effect Induced Interfacial Water Restructuring Accelerates Zinc-Catalyzed Hydrodeoxygenation

The deoxygenation of biomass-derived molecules is thermodynamically challenging yet essential for their conversion to commodity chemicals. Metallic zinc is a promising material for deoxygenation due to its strong reductive properties, but sluggish kinetics and harsh reaction conditions detract from practical application. Here, we hypothesize that zinc-catalyzed hydrodeoxygenation could be limited by inefficient proton transport due to disordered interfacial water structure. Using the transformation of dihydroxyacetone to acetone as a model reaction, we identified the rate-determining step to be an Eley-Rideal-type proton-coupled electron transfer from water to the hydroxyacetone intermediate. Applying an electric field accelerates this step by restructuring the interfacial hydrogen-bond network and promoting direct proton transfer, thereby enabling a 10³-fold increase in surface-area-normalized turnover frequency and Faradaic efficiencies of 63%-70% at current densities up to 300 mA/cm². These findings highlight interfacial water restructuring as a powerful lever for enhancing hydrodeoxygenation efficiency.