A research team from Hong Kong Polytechnic University, the University of Oxford, and the National Synchrotron Radiation Research Center has developed a new membrane-electrode-assembly (MEA) system for stable electrocatalytic reduction of carbon dioxide (CO2). Described in a paper published in Nature Energy, the system does not rely on alkali-metal electrolyte and utilizes pure water as the anolyte. This allows for a prolonged stable operation, addressing a significant challenge in existing systems.
The electrocatalytic reduction of CO2, which converts the greenhouse gas into useful chemicals and feedstock using renewable energy, is a promising approach to mitigate greenhouse gas emissions. However, existing systems face limitations such as poor stability over extended periods.
The researchers aimed to create a new electrolysis architecture that suppresses carbonate formation during CO2 reduction and enables prolonged stable operation. They designed an AEM+PEM assembly membrane-electrode assembly (APMA MEA) architecture with pure water as the anolyte.
The APMA MEA system comprises two distinct membranes (AEM and PEM), a cathode catalyst (stepped-surface Cu), an anode catalyst (Pt/Ti), and pure water as the anolyte. One of its notable advantages is that it does not require additional chemicals to initiate reactions, relying only on pure H2O as the electrolyte. This characteristic makes it potentially easy to scale up to an industrial level.
The APMA MEA system was found to effectively suppress carbonate formation during CO2 reduction, achieving stability for the hydrocarbon C2H4 for an impressive 1,000 hours. The researchers believe that their breakthrough could contribute to industrializing CO2 electrocatalysis and reducing carbon emissions on an industrial scale. In future work, they plan to enhance the current density and energy efficiency of the APMA system.