Scalable electrosynthesis of propionic acid via 1-propanol oxidation on nickel hydroxide electrodes in a diaphragmless electrolytic cell

Abstract

Biomass valorization via electrosynthesis offers an eco-friendly route under mild conditions. Herein, propionic acid from 1-propanol was produced on nickel hydroxide electrodes (Ni(OH)2/NF) using the 1-propanol precursor in a diaphragmless electrolytic cell. Systematic optimization of key operational parameters—including current density, NaOH concentration, 1-propanol concentration, and reaction time—was carried out to maximize product efficiency. Under optimal operating conditions (0.35 mol·L−1 of 1-propanol, 0.5 mol·L−1 of NaOH, 40 mA·cm−2 of current density and 5 h of reaction time), this multivariate strategy achieved a Faradaic efficiency of 94.11% and a yield of 70.42% for propionic acid. Notably, scalability was validated through gram-scale synthesis in a single batch, producing tens of grams of propionic acid and highlighting the practical viability of the diaphragmless configuration. Combined electrochemical analyses and density functional theory (DFT) calculations elucidate the reaction mechanism, revealing that Ni(OH)2/NF facilitates the dehydrogenation and oxidative coupling steps critical to selective propionic acid formation. This study not only establishes a green and efficient route for value-added chemical production from biomass-derived alcohols but also demonstrates the industrial potential of diaphragmless electrolytic systems.