The Turbine Blades-Embedded Electrolyzer for Boosting CO2RR Performances

Aqueous CO₂ electrolysis is a promising technology for closing the carbon cycle and de-fossilizing industrial processes. In addition to vigorously developing advanced materials for electrocatalysts and ion-exchange membranes, challenges such as media flow management, module stability, and force distribution are highly associated with improving the process performance and developing a stackable cell concept to meet industrially relevant levels. The design of the “zero-gap” membrane electrolyzer assembly achieved a prevailing position in laboratory and primary industrialization. However, the utilization of CO₂ is less than 50% despite using a cationic ion-exchange membrane or bipolar membrane to reduce the CO₂ crossover between anode and cathode, making it economically less attractive. This could be attributed to the gas path architectures in the gas chamber, which touches the gas diffusion electrode (GDE) from both sides of the electrode. Herein, we reported a promising modified electrolyzer architecture concept with hierarchically continuous flow channels and GDEs. The meticulous turbine blades were introduced in the cylindrical-shaped gas path architecture to increase the CO₂ media vortex for compulsive reaction with electrocatalysts, thereby enhancing CO₂ utilization, reduction of applied cell voltage, and selectivity. The structure was built by powder bed fusion-based 3D printing and embedded with electrochemically restructured zinc oxide nanoparticles as cathode electrocatalysts. The effect of these modifications on the cell voltage, selectivity, and overall conversion was investigated at 100 mA/cm² with varying CO₂ feed gas flow, concentration, and humidity. This as-fabricated electrolyzer was designed to be modular and provide the cell with mechanical integrity and allowed an ionic and electric contact over the entire active cell area, which is required for both stacking and upscaling of the cell. This concept-proof configuration promises ~70% CO₂ utilization and displayed 95% CO₂ to CO conversion at 3V with 180 mA/cm², showing efficient and scalable CO₂ electrolysis without a notable increase in operation cost, and has high potential for practical application.