Sustaining atmospheric plasma with nanosecond microwave pulses to increase the efficiency of CO2 splitting

An atmospheric CO2 plasma sustained in a coaxial torch with short, nanosecond microwave pulses is compared with a plasma sustained with continuous microwave power. The use of a novel, advanced solid state microwave generator enables to supply pulsed microwave energy with ON and OFF times from 50 ns to 200 s. Analysis of both CO2 conversion and energy efficiency made for different pulse lengths, duty cycles and gas flows has shown the advantage of pulsed energy supply against CW operation. The work also features the accurate measurement of the absorbed microwave power in the plasma, which is demanding for the correct estimation of process efficiency.