Engineering of Copper-Based Nitrogen-Rich Covalent Triazine Frameworks (Cu@CTFs) as Highly Efficient Electrocatalysts for Carbon Dioxide Reduction

In this study, we employed a simple and efficient method to synthesize two porous covalent triazine frameworks (CTFs) using a cyanuric chloride core with both 1,4-diaminobenzene and 1,1‵-biphenyl-4,4‵-diamine, which were subsequently embedded with copper acetate, giving Cu@CTF electrocatalysts. The composite materials were comprehensively characterized, and their performance in the electrochemical CO₂ reduction reaction (CO₂RR) was systematically evaluated. The Cu@CTFs exhibited significant enhancements in CO₂RR performance compared to their unmodified counterparts. The as-synthesized Cu@CC-BP-CTF electrocatalyst possessed exceptional catalytic efficiency due to its highly porous structure and great surface area. At a voltage of 1.6 V versus RHE, it achieved a maximum CO Faradaic efficiency of 39%. In addition, the activity of this system was characterized by a partial current density of around 85.8 mAcm⁻² in a flow-cell configuration. Furthermore, this catalyst demonstrated remarkable stability over 10 h, highlighting its significant potential for real-world utilization in CO₂RR. The Cu@CC-BP-CTF electrode exhibited superior CO₂RR activity, higher mass activity, and improved charge transfer rates incomparable to the unmodified counterpart. These findings highlight the crucial role of copper in modifying the surface properties of electrocatalysts, providing valuable insights into the design strategies for advanced materials with enhanced performance in electrochemical applications.