Coulomb Explosion of Metastable Dications in Space and Lab Using Plasma-Assisted Conversion of CO2 to Fuels

Molecular dications, which are doubly charged cations, play a significant role in flames, plasma chemistry and physics, and the chemistry of planetary upper atmospheres. These exotic species can store substantial energy at a molecular level. This energy, that can be often of several electron volts, can be released as the translational energy of two mono-cation fragments produced by a Coulomb explosion. Because of this, molecular dications have been proposed as a possible novel type of alternative propellant. In the early 2000s, the scientific community began discussing the potential role of molecular dications in planetary upper atmospheres. This led us to hypothesize a reason for the unexpectedly low O+ concentration in Mars’ atmosphere, as recorded by VIKING 1 lander and MARINER 6 spacecraft. We developed the suggestion that the atmospheric scarcity of O+ could be due to the dissociative double photoionization of CO2 molecules, resulting in the Coulomb explosion of the metastable intermediate CO22+ dication. This process could, in principle, contribute to the gradual erosion of Mars’ atmosphere. Building on these findings, we leveraged our three decades of experience in plasma generation and characterization to investigate enhancing the chemical reactivity of CO2 + H2 mixtures used in methanation processes through plasma-assisted catalysis. Our approach involves generating plasmas in CO2 + H2 mixtures and examining whether the formation of CO22+ dications, followed by Coulomb explosion and the production of CO+ and O+ fragments with high relative kinetic energy (approximately 6.0 eV), can increase chemical reactivity. This increased reactivity could facilitate hydrogenation of carbon dioxide into organic molecules suitable for use as fuels.