Insight into Carbon Hybrid and Interfacial Modulation for High-Performance Electrosynthesis of Ethylene Glycol

Electrocatalytic reduction of formaldehyde with H2O on a carbon-based catalyst has shown a promising route for ethylene glycol (EG) production; however, most of the corresponding parameters are still unsatisfactory to support industrial applications. In this work, the carbon–electrolyte interfaces by regulating carbon hybrid and introducing quaternary ammonium-based ionic liquids were investigated to improve Faradaic efficiency of EG (FEEG) with high durability at high current density (j) and low temperature. The nondefective sp2-hybridized carbon (sp2-G) was demonstrated as the main active site leading to EG. Remarkably, a high FEEG of 92.0% was thus achieved on ND-1400 at −1000 mA cm–2 with 2 wt % dodecyl trimethylammonium chloride at 50 °C. The performance remained basically unchanged within 40 h of electrolysis at −200 mA cm–2. Experimental combined theoretical studies demonstrated the formation of EG versus methanol on the sp2-G carbon is slightly disfavored in thermodynamic. However, the FEEG and the applied potential, at high j, are mainly influenced by the mass transfer of H2O while exhibiting opposite correlations. The techno-economic assessment suggested this electrosynthesis of EG is profitable at the current density as high as −400 mA cm–2 using renewable energy-based electricity in southwest China.