Three-dimensional multiphysics simulation on reaction and thermal characteristics of MEA electrolyzer for CO₂ reduction

Thermal phenomena during the CO₂ electro-catalytic reduction reaction significantly impact product selectivity and formation rates, while also inducing detrimental thermal stress in the membrane electrode assembly. A three-dimensional simulation is urgent to understand the thermal phenomena in electrolyzer. In this work, three-dimensional multiphysics simulation is developed to simulate a membrane electrode assembly CO₂ electrolyzer. The results have been represented by reaction, heat generation and transfer characteristics, synthetically researched heat transfer, fluid dynamic, mass transfer and electrochemistry in three-dimensional procedures. In this simulation, optimal condition to balance production and thermal phenomena requires a voltage at 3 V, temperature at 293 K and cathode CO₂ supply at 50 mL/min. Temperature beneath 303 K benefited liquid phase product including methanol while between 303 K and 323 K favored gaseous product like CO. The three-dimensional analysis reveals that temperature gradients exceeding 10 K/cm emerge above 2.25 V in the vertical direction and 2.5 V in the horizontal direction. Temperature beyond 293 K intensified these thermal phenomena. Moreover, the temperature gradients increase more severely in the vertical direction than in the horizontal direction as the ambient temperature rises. The components of heat had been quantified that electrochemistry heat will take a majority at 52 % of heat component when reaches 3 V. At initial phase of low voltage beneath 2.5 V and temperature below 293 K, ohm heat will take the majority at 36 %. These findings highlight the necessity of proactive thermal management to optimize reactor performance and longevity. This research underscores the importance of a thermal management system in electrolyzers and prior to the practical application of CO₂ electro-catalytic reduction technology.