A high-throughput femtosecond laser-engineered 3D microfluidic chip for efficient chemical transformation of carbon dioxide to value-added chemicals

Efficient conversion of low reactive CO₂ within a short residence time of flow chemistry presents a challenge. We have tackled this issue by developing 3D microfluidic chips (MFCs) with high-density, small-diameter, and large-volume for CO₂ gas–liquid reactions using femtosecond laser technology. Our innovative design effectively shortens reaction times while satisfying the required temperature and pressure conditions. One of the key features is the integration of the 3D Barker's transform structure, which provides an efficient gas–liquid contact area for mass and heat transfer, even at low Reynolds numbers. As a proof of concept, we synthesize 2,4,5-trifluorobenzoic acid and various other fluorinated carboxylic acids in 3D MFCs using Grignard reagents and CO₂. Impressively, the Grignard reagents can be generated in situ and utilized at room temperature, and the CO₂ carboxylation reaction with 3D MFCs takes only 40 s with a yield of 97 %. Our findings highlight the feasibility of this multifunctional, efficient, and fast CO₂ flow conversion process, providing a valuable tool to produce value-added chemicals via 3D MFCs techniques.