Microfluidic Printing-Induced Dynamic Splitting of Conductive MOF to Expose High-Density Active Sites for Boosted CO₂...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Electrocatalytic CO2 reduction (CO2RR) is crucial for carbon recycling, but scalable synthesis of well-defined catalysts is a significant hurdle.
• Existing methods for conductive metal-organic frameworks (cMOFs) often lack scalability and precise structural control.

Purpose of the Study:

• To develop a rapid, scalable microfluidic printing strategy for the dynamic splitting and directional construction of cMOFs.
• To investigate the impact of microfluidic processing on cMOF structure and its performance in electrocatalytic CO2 reduction.

Main Methods:

• Utilized microfluidic channels to induce shear forces from laminar flow, controlling cMOF crystallization.
• Investigated the suppression of interlayer interactions and promotion of 2D in-plane crystallization.
• Characterized the resulting ultrathin lamellar cMOF structures (MF-cMOF Qx/ty) and compared them to conventional synthesis (ST-cMOF).

Main Results:

• Microfluidic processing yielded ripple-like ultrathin lamellar cMOFs (11-2 nm thickness) with preferentially exposed (001) planes in minutes.
• The optimized MF-cMOF Q1.28/t5 demonstrated a high yield (0.29 g h-1) and space-time yield (502 kg m-3 day-1), a 282-fold enhancement over conventional methods.
• MF-cMOF Q1.28/t5 achieved a methane Faradaic efficiency (FE) of 79.6% at -1.2 V vs. RHE, outperforming conventional cMOFs by 1.8 times.

Conclusions:

• Microfluidic printing is an effective strategy for producing structurally defined MOFs with enhanced properties.
• The developed method enables sustainable and industrially scalable CO2 electroreduction, offering a promising route for carbon recycling.
• Ultrathin lamellar cMOFs with increased active site density significantly enhance reactivity for CO2RR.