Electrolyte Influence on the Electrochemical Oxidation of Anhydrous Methanol to Dry Formaldehyde

Abstract

The electrification of the formaldehyde synthesis is investigated as a sustainable alternative to the current thermal approach. The formation of formaldehyde in anhydrous methanol achieves higher Faraday efficiencies than in aqueous conditions, yet operates at higher cell potentials. The electrolyte is an influential factor, and its role is not yet understood. Here, we report on the electrolyte's effect on the electrochemical formaldehyde synthesis in anhydrous methanol. After an electrolyte screening, four electrolytes were chosen for an in-depth analysis of the supporting electrolyte's ion influence. Among the tested supporting electrolytes, the anion dominates the conductivity and viscosity while larger cations favor the formation of formaldehyde. Understanding the electrolyte properties is crucial for large-scale industrial synthesis.