Carbon Dioxide Capture by a Hydrothermally Synthesized Water-Resistant Zinc-Oxalate-Aminotriazolate Framework.

Selective capture of carbon dioxide (CO2) from flue gas employing physisorbents represents an appealing approach owing to its potentially low energy penalty and cost-effectiveness. Microporous metal-organic frameworks (MOFs), characterized by their highly customizable pore structure and functionality, offer significant promise in this field. However, challenges such as thermal/moisture resistance, green/scalable synthesis, and adsorption durability remain unresolved. Here, we demonstrate the effective capture of CO2 from flue gas using a microporous zinc-oxalate-aminotriazolate (Zn-OX-ATZ) framework material. Zn-OX-ATZ is synthesized directly in water from zinc oxalate and 3-amino-1,2,4-trazole, achieving high atom economy. It displays a CO2 adsorption capacity of 2.29 mmol g-1 at 318 K and 0.15 bar, with a CO2/N2 selectivity exceeding 78000. Notably, its structural integrity and CO2 adsorption capability are fully maintained under highly humid conditions, as evidenced by over 50 adsorption-desorption cycles. The practical applicability of Zn-OX-ATZ for industrial CO2 capture has been experimentally validated using simulated flue gas at the kilogram scale. Additionally, we have elucidated the underlying mechanism and adsorption domains of CO2 in the presence of H2O at the molecular level through a combination of gas-loaded single-crystal X-ray diffraction, in situ infrared spectroscopy, and ab initio modeling. This study presents a durable physisorbent for CO2 capture, characterized by well-balanced adsorption capacity and selectivity, high water stability and resistance, green preparation, and, therefore, strong practical applicability.