Exploration of Quantum Computing in Materials Discovery for Direct Air Capture Applications

Direct air capture is a promising method for mitigating climate change. Solid sorbents, such as metal-organic frameworks, have been considered for this task, but their potential for deployment at scale has not been fully realized. The computational discovery of sorbent materials is a daunting task, given the vast search space, and the fact that their real-world performance depends on their ability to selectively bind CO2 molecules while avoiding other more abundant flue gas components. Quantum computing can potentially accelerate the discovery of novel materials for direct air capture as an alternative way to compute binding energies. In this work, we demonstrate methods and algorithms that enable these calculations in current quantum computing devices. We simulate the potential energy surfaces of CO2, N2, and H2O molecules at the Mg+2 metal center that represents the binding sites of typical metal-organic frameworks. We apply the qubit-ADAPT-VQE technique to run simulations on both classical and quantum hardware, and achieve reasonable accuracy while maintaining hardware efficiency, even when compared to more established methods such as UCCSD-VQE.