Carbon dioxide (CO2) electrolysis powered by renewable electricity can turn CO2 into useful fuel and chemicals. Notwithstanding, one of the key difficulties ruining CO2 electrolysis for down-to-earth application is the serious carbon misfortune under acidic and impartial circumstances, bringing about low CO2 use effectiveness (50%).
Recently, a group of researchers led by Professors A new approach for acidic CO2 electrolysis that is both carbon- and energy-efficient has been proposed by Bao Xinhe, Wang Guoxiong, and Gao Dunfeng from the Chinese Academy of Sciences (CAS).
On February 23, this study was published in Energy & Environmental Science.
By altering the anolyte composition and the input CO2 pressure in an acid membrane electrode assembly (MEA) electrolyzer, the researchers were able to fine-tune the microenvironments—local concentrations of H+, K+, and CO2—of the Ni-N-C cathode catalyst. Profiting from custom-made impetus microenvironments, they accomplished acidic CO2 electrolysis to CO at modern current densities with high CO2 productivity and high energy effectiveness.
“This work advances our understanding of modifying catalyst microenvironments for carbon-efficient CO2 electrolysis toward practical use.”
Prof. Wang.
They achieved full cell energy efficiency of 39% and CO faraday efficiency of 95% at 500 mA/cm2 under ideal reaction conditions. The CO2 loss was reduced by 86% when compared to alkaline electrolysis, and the single-pass CO2 utilization efficiency was as high as 85%.
In addition, they have demonstrated that the initial *CO2 intermediate was stabilized by the presence of H+ and K+, resulting in enhanced CO formation in accordance with theoretical calculations.
They likewise gathered a corrosive/soluble pair CO2 electrolysis framework, exhibiting carbon-efficient CO2 transformation to multicarbon items (C2+) by means of a CO2-CO-C2+ course.
Prof. Wang stated, “This work provides new insights into tuning catalyst microenvironments for carbon-efficient CO2 electrolysis in the direction of practical application.”
More information: Hefei Li et al, Tailoring acidic microenvironments for carbon-efficient CO2 electrolysis over a Ni–N–C catalyst in a membrane electrode assembly electrolyzer, Energy & Environmental Science (2023). DOI: 10.1039/D2EE03482D
