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

Electrocatalytic CO2 reduction (CO2RR) is vital for carbon recycling, yet scalable production of well-defined catalysts remains challenging. Herein, we develop a rapid and scalable microfluidic printing strategy that enables dynamic splitting and directional construction of conductive metal-organic framework (cMOF). Within the confined microfluidic channel, the shear forces induced by laminar flow play a dominant role in effectively suppressing interlayer interactions along the vertical direction, while simultaneously promoting 2D in-plane crystallization. Consequently, cMOF with preferentially exposed (001) planes are formed within only several minutes. Compared with the conventional perpendicular rod-like ST-cMOF, microfluidic-processed MF-cMOFQx/ty series exhibit ripple-like ultrathin lamellar with the substantially reduced thickness of 11-2 nm. Such ultra-thin features dramatically increase the density of accessible active sites, enhancing reactivity toward CO2RR. Besides, benefiting from the continuous flow and high throughput, the optimized MF-cMOFQ1.28/t5 achieves a remarkable yield of 0.29 g h-1 and an ultrahigh space-time yield of 502 kg m-3 day-1, representing 282-fold enhancement over conventional synthesis. Moreover, MF-cMOFQ1.28/t5 delivers CH4 FE of 79.6 % at -1.2 V vs. RHE, outperforming a 1.8-fold improvement of ST-cMOF. This work establishes microfluidic printing as an effective strategy for structurally defined MOF and highlights the potential for sustainable and industrially scalable CO2 electroreduction.