【Frontiers in HaiChuan Chemical Technology】Chinese researchers make new progress in the electrocatalytic reduction of carbon dioxide using acidic membrane electrodes

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Recently, Chinese researchers have made new progress in the field of electrocatalytic carbon dioxide reduction using acidic membrane electrodes. The research team proposed using porous membranes in place of ion exchange membranes, achieving highly selective and stable electrocatalytic conversion of carbon dioxide under acidic conditions, thus providing a new solution for the sustainable utilization of carbon dioxide. 　　This research achievement was obtained by the research team led by Professor Luo Jingshan from the School of Electronic Information and Optical Engineering at Nankai University, and was recently published in Nature Communications. 　　Carbon dioxide is the main greenhouse gas at present. How to turn carbon dioxide into a valuable resource is key to achieving carbon peak and carbon neutrality. For a long time, zero-gap membrane electrode carbon dioxide electrolyzers have been regarded as an important approach for the conversion and utilization of carbon dioxide due to their high energy efficiency and high level of integration. However, zero-gap membrane electrode electrolyzers often face problems such as salt deposition, water leakage, and hydrogen evolution side reactions during operation, making it difficult to balance stability and carbon utilization efficiency. 　　“Just as water scale forms in kettles in daily life, the ‘scale’ that appears in electrolyzers can easily clog pipes and damage equipment, causing the reaction to stop quickly and resulting in great instability. ”Wei Shilei, a member of the research team and a 2022 doctoral student at the School of Electronic Information and Optical Engineering at Nankai University, explained. 　　To address this challenge, the team proposed replacing the core \"filtering component\" by using porous membranes in place of traditional ion exchange membranes, thereby creating a zero-gap membrane electrode cell in an acidic environment. Porous membranes with the appropriate pore size and hydrophilicity were selected to achieve a balance in mass transfer, thereby fundamentally improving the reaction conditions. This design effectively suppresses the salt deposition and hydrogen evolution side reactions, enabling the system to maintain excellent performance even at high current densities. 　　Experimental results show that under acidic electrolyte conditions, the porous membrane electrolyzer achieves a carbon monoxide Faradaic efficiency of up to 85% at a current density of 400 mA cm-2, which is significantly better than that of the ion exchange membrane system. 　　Meanwhile, the research team conducted a long-term stability test lasting 200 hours continuously; the proportion of carbon monoxide in the carbon dioxide reduction products was close to 100%, there was very little hydrogen as a by-product, and no salt precipitation occurred. In tests using electrolyzers with a large area of 100 cm2, the device was able to operate stably for over 120 hours, with the proportion of carbon monoxide in the carbon dioxide reduction products remaining at around 90%, thereby fully demonstrating the scalability and industrial application potential of this technology. 　　“This achievement provides new membrane usage and design strategies for acidic membrane electrode carbon dioxide reduction electrolyzers, laying the foundation for the electrosynthesis of high-value carbon-based fuels and chemicals in the future. ”Luo Jingshan said.