Enhanced n-Propanol Electrocatalytic Oxidation by Porous Electrode under Flow-Through Operation for Improving Mass Transfer and Selectivity

A porous electrode with Co(CO3)0.5OH immobilized in the pores of nickel foam was developed for enhanced n-propanol electrocatalytic oxidation under flow-through operation for improving mass transfer and selectivity. At 3.05 × 10–3 m·s–1 flow velocity and 0.25 M n-propanol concentration, the limiting current density reached 280 mA·cm–2 (96.16% higher than no flow-through conditions), with the mass transfer coefficient improving from 5.54 × 10–6 to 1.09 × 10–5 m·s–1. The conversion of n-propanol reached 78%, and the selectivity of propionic acid and the Faraday efficiency reached 99% and 99%, respectively, after 12 h reaction. The kinetic model analysis indicates that as the flow velocity increases from 0 to 3.05 × 10–3 m·s–1, the reaction rate constant for the oxidation of propionaldehyde to propionic acid is enhanced by 13.35 times, with enhanced selectivity for propionic acid obtained. COMSOL Multiphysics simulations implied that a uniform concentration field and reaction residence time can be achieved under the flow-through operation.