Producing valuable multicarbon (C₂₊) chemicals and fuels like ethylene via catalytic conversion of carbon monoxide (CO) derived from coal, natural gas, and biomass is an important nonpetroleum route. The thermocatalytic CO conversion processes such as Fischer-Tropsch synthesis (FTS) suffer from substantial CO₂ emission as well as the formation of undesired methane by-products.

Renewable energy-driven CO electrolysis is an emerging catalytic CO conversion route. This reaction proceeds with water as a hydrogen source under ambient conditions and can electrochemically eliminate the formation of CO₂ by applying a negative potential on CO molecules.

Recently, a research team from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) achieved high-rate electrosynthesis of C₂₊ chemicals and fuels via CO electrolysis. This study was published in Nature Communications.

The researchers developed a Cu nanoparticle catalyst with high-density grain boundaries (GBs) via a facile wet-chemistry synthesis approach. Combining the Cu catalyst and advanced alkaline membrane electrode assembly electrolyzers developed by the team, they achieved a C₂₊ partial current density as high as 4.35 A cm^-2 at a low cell voltage of 2.78 V, with a C₂₊ Faradaic efficiency of 87% and a notable C₂₊ yield as high as 85%.

The results of operando Raman spectroscopy and density functional theory calculation revealed that the abundant grain boundaries of Cu nanoparticles facilitate CO adsorption and C-C coupling, thus rationalizing the impressive C₂₊ production.

Using the above Cu catalyst and an electrolyzer stack with five 100 cm² membrane electrode assembly, a scale-up demonstration achieved high C₂₊ and ethylene formation rates of 118.9 mmol min^-1 and 1.2 L min^-1 at a total current of 400 A, respectively.

"This work demonstrates the great promise of CO electrolysis as a sustainable and practical route for the electrochemical synthesis of valuable C₂₊ chemicals," said Prof. GAO Dunfeng, one author of this study. "This work highlights the significance of coupling catalyst design and device design in developing highly-efficient electrolysis technology," said Prof. WANG Guoxiong, another author of this study.