Goal
Generate molecular oxygen directly from carbon dioxide via energetic ion-surface collisions.
Problem
Need for efficient CO_2 reduction pathways and sources of O_2 for space-flight life-support, planetary habitability, and astrophysical O_2 formation.
Concept Summary
When hyperthermal CO_2^+ ions impact a solid surface (e.g., Au) they undergo a two-step sequential collision. The first O atom strikes the surface, then the CO fragment collides with a second surface atom. This impulsive energy transfer bends the CO_2 molecule into a strongly bent configuration, which then dissociates to C + O_2. The O_2 product is ionized by charge transfer from the surface, allowing detection of O_2^+ and O_2^-. First-principles molecular dynamics simulations reproduce the experimental ion energy and velocity distributions and predict a neutral O_2 yield of ~0.6-0.8 % at incidence energies around 55-70 eV.
Principles
- Collision-induced dissociation
- Sequential two-step surface collision
- Bending of CO_2 to a strongly bent geometry
- Surface-mediated electron transfer
Scientific Domains
Materials
- Gold (Au) surface
- Carbon dioxide (CO_2) gas
Mechanisms of Action
- Hyperthermal ion-surface collisions
- Intramolecular rearrangement of CO_2
- Charge transfer ionization from metal surface
Energy Sources
Applications
- Spacecraft life-support (O_2 generation from CO_2)
- Atmospheric CO_2 utilization
- Astrophysical modeling of O_2 formation
Claimed Performance
Neutral O_2 yield up to 0.8 % (+/-0.2 %) at ~=70 eV incidence; ionized O_2^- yield ~=33 % of O_2 products.
Experimental Evidence
Ion-beam scattering experiments showing O_2^+/O_2^- signals; kinematic analysis matching binary-collision theory; first-principles MD simulations reproducing ion energy and velocity distributions.
Limitations
- Very low neutral O_2 yield (<1 %)
- Requires hyperthermal ion beam and metal surface
- Neutral O_2 not directly measured in the study
