Chae, Sang Youn Kim, Jae Hong Maeng, Jung Hun Hwang, Bohyeon Yang, Gun Sik Jun, Minki Kim, Jin Young Park, Eun Duck 2025-07-18T07:00:12Z 2025-07-18T07:00:12Z 2025-07-18 2025-08 1385-8947 https://pubs.kist.re.kr/handle/201004/152787 The increasing concentration of anthropogenic CO2 in the atmosphere is exacerbating global warming, making the need for carbon reduction technologies even more urgent. While photovoltaic cell (PV)-assisted electrochemical carbon dioxide reduction (CO2RR) is a promising approach for converting carbon dioxide into value-added chemicals and fuels, its practical implementation is hindered by the low selectivity and stability of electrocatalysts, particularly in seawater electrolytes. Unlike purified potassium bicarbonate (KHCO3) electrolytes, natural seawater electrolyte presents additional challenges, such as catalyst deactivation due to unwanted metal ions and competitive side reactions, and instability under fluctuating solar irradiation in PV-electrolysis systems. This study explores the role of ionomer selection in silver-based CO2RR under natural solar-driven PV-electrolysis in seawater. Comparing Nafion and Sustainion, we have found that Sustainion significantly enhances carbon monoxide selectivity (>95 % Faradaic efficiency) by suppressing the hydrogen evolution reaction (HER) and facilitating bicarbonate transport, reducing calcite-induced deactivation. Moreover, silver and Sustainion electrodes maintain stable performance under fluctuating sunlight, unlike silver and Nafion, which degrade quickly due to limescale formation. These findings emphasize the importance of optimizing ionomer-catalyst interactions and operational conditions for durable seawater-based carbon dioxide electrolysis. The integration of ionomer-engineered silver catalysts with PV-electrolysis presents a promising approach for scalable and sustainable carbon dioxide conversion. English Elsevier BV Ionomer-driven selectivity control in natural sunlight-powered CO2 electrolysis using Ag electrodes in seawater Article 10.1016/j.cej.2025.164544 1 Chemical Engineering Journal, v.518 Chemical Engineering Journal 518 N scie scopus 001517504200001 Engineering, Environmental Engineering, Chemical Engineering Article ELECTROCHEMICAL REDUCTION FLOW CELL CONVERSION CARBON-DIOXIDE Seawater CO CO2 reduction Electrochemistry Ionomer Ag electrode Seawater CO Electrochemistry Ionomer Ag electrode