(133b) Emerging Electrosynthesis Processes to Decarbonize the Chemical Industry

Electrifying chemical productions is a potential approach to decarbonizing the chemical industry. Currently, 21% of the global greenhouse gas emissions comes from the industry sector, while chemical manufacturing accounts for the largest share of industrial carbon emissions. The electrochemical processes, when powered by renewable electricity, have lower carbon footprints than conventional thermochemical routes. The rapid development of renewable energy provides opportunities in electrifying chemical production and decarbonizing chemical industry. In this presentation, I would like to use electrosynthesis of value-added ethylamine and ethylene glycol as two examples.

First, I would like to talk about electroreduction of acetonitrile for selective synthesis of primary amines. Primary amines are important organic building blocks; however, the synthesis is often hindered by the poor selectivity because of the formation of secondary and tertiary amine byproducts. We report an electrocatalytic route to produce ethylamine selectively through an electroreduction of acetonitrile at ambient temperature and pressure. Among all the electrocatalysts, Cu nanoparticles exhibited the highest ethylamine Faradaic efficiency (FE, ~96%) at -0.29 V versus reversible hydrogen electrode (RHE). In a flow cell configuration, an ethylamine partial current density of 846 mA cm^-2 was achieved using the Cu catalyst at -0.73 V vs. RHE in a 1 M NaOH electrolyte containing 12 wt.% acetonitrile. Moreover, the reaction mechanism of acetonitrile electroreduction was investigated by operando electrochemical differential mass spectroscopy and density functional theory calculations.

In the second part of this presentation, I would like to share our recent progress on ethylene glycol electrosynthesis. Ethylene glycol is mainly used as precursor of polyethylene terephthalate (PET) and antifreeze, with a world annual capacity of 42.09 Mt/yr. Conventionally, ethylene glycol is produced through ethylene partial oxidation at high temperature, followed by ethylene oxide hydrolysis, which has a significant carbon footprint. Here we report an electrochemical approach for ethylene glycol electrosynthesis with >90% selectivity towards ethylene glycol at a current density of 200 mA cm^-2. The reaction mechanism is investigated through operando differential electrochemical mass spectrometry experiment, isotopic-labeling experiment, and density functional theory calculation.