Development of a ReaxFF Force Field for Aqueous Phosphoenolpyruvate as a Novel Biomimetic Carbon Capture Absorbent

YH Huang and AS Wexler and KJ Bein and R Faller, JOURNAL OF PHYSICAL CHEMISTRY C, 126, 9284-9292 (2022).

DOI: 10.1021/acs.jpcc.2c01841

Phosphoenolpyruvate (PEP) found in C4 plants could be a novel green absorbent in biomimetic carbon capture through its crassulacean acid metabolism (CAM) mechanism and could potentially substitute the most commonly used absorbent monoethanolamine in future postcombustion capture systems. In this study, a new ReaxFF model has been developed to describe the CAM reactions involving PEP and the atomic interactions in the P/C/O/H system. The ReaxFF force field parameters were fitted against quantum mechanical (QM) training data for partial charges, molecular structures, bond dissociation energies, reaction energies, and activation energies. Second-generation water parameters were combined with P/C parameters for more accurate water description, and P's electrostatic parameters were specially treated to correct P/O interactions. The developed P/C/O/H ReaxFF model was able to reproduce the training set for structures and energetics of the molecules and reactions involved in the CAM process and accurately describe the aqueous bicarbonate and PEP systems. Molecular dynamics simulations using this ReaxFF model depict how bicarbonate reacts with PEP and in solution and determine the impact of local structure on reactions necessary to perform carbon capture by using PEP, which enables the potential design of PEP variant as the optimal carbon capture absorbent.

Return to Publications page