adsorption in metal organic frameworks

Global warming caused by excessive emission of greenhouse gases (mainly CO₂) into atmosphere imposes profound changes in environment. For curbing the global temperature increase, effective approaches for carbon capture are needed. As porous sorbents, metal organic frameworks (MOFs) are promising candidate-materials that potentially combine high CO₂ uptake and CO₂/N₂ selectivity. However, it is still challenging to computationally identify the best suited species within the hundreds of thousands of MOF structures known today. First-principles-based simulations of CO2 adsorption in MOFs would provide the necessary accuracy, however, they are impractical for screening purpose due to the high computational cost. Classical-force-field based simulations would be computationally feasible, however, they do not provide sufficient accuracy. Here, we report the quantum-informed machine-learning force fields (QMLFF) for atomistic simulations of CO₂ in MOFs. We demonstrate that the method has a much higher computational efficiency (~1000 times) than first-principles one while maintaining quantum-level accuracy. As a proof of principle, we show that the QMLFF-based atomistic simulations can yield various physical quantities comparable to experimental results. The combination of machine learning and atomistic simulation paves the way for modeling CO₂ capture by MOFs both accurately and efficiently.