Power-to-chemical
technologies with CO2as feedstock
recycle CO2and store energy into value-added compounds.
Plasma discharges fed by renewable electricity are a promising approach
to CO2conversion. However, controlling the mechanisms
of plasma dissociation is crucial to improving the efficiency of the
technology. We have investigated pulsed nanosecond discharges, showing
that while most of the energy is deposited in the breakdown phase,
CO2dissociation only occurs after an order of microsecond
delay, leaving the system in a quasi-metastable condition in the intervening
time. These findings indicate the presence of delayed dissociation
mechanisms mediated by CO2excited states rather than direct
electron impact. This “metastable” condition, favorable
for an efficient CO2dissociation, can be prolonged by
depositing more energy in the form of additional pulses and critically
depends on a sufficiently short interpulse time.