3D‐Printed Copper‐Based Gas Diffusion Electrodes with a Tunable Bilayer Architecture for Controlled CO 2 Electroreduction Selectivity

Electrochemical CO₂ reduction reaction (CO₂RR) offers a promising pathway for converting CO₂ into value-added chemicals, contributing to climate change mitigation and the advancement of sustainable chemical production. In CO₂RR flow cell systems, developing gas diffusion electrodes (GDEs) with enhanced electrochemical performance is crucial for enabling commercial applications. However, the exploration of copper-based self-supported GDEs is constrained by a narrow selection of substrates. 3D printing technology offers an approach to creating intricate structural components, but its integration with GDE fabrication remains unexplored. Here, a 3D-printed copper-based GDE, fabricated via fused deposition modeling (FDM) and featuring a tunable porous structure, is successfully applied in a CO₂RR flow cell. Under specified operating conditions, adjusting the thickness of the electrode's solid layer influenced H₂ selectivity, while modifying the thickness or density of the grid-like infill layer allowed for tuning C₂H₄ and CO selectivity. Notably, the S2I2 electrode configuration, with 0.2 mm-thick solid and infill layers, achieves 47% C₂₊ product selectivity at a current density of 200 mA cm^-2. This work demonstrates the potential of 3D printing for designing architecture-tailored GDEs and tuning CO₂ electroreduction product distributions.