Real-time measurement of axial temperature in a coaxial dielectric barrier discharge reactor and synergistic effect evaluation for in-plasma catalytic CO2 reduction

Due to serious difficulty in the measurement of catalyst-bed temperature (T-b) for in-plasma catalysis (IPC), the evaluation of the IPC synergistic effect is still disputed. Herein, we reported a real-time measurement of axial temperature (T-ax), which is much closer to T-b than wall temperature (T-w), using a thermocouple in a catalyst-packed coaxial dielectric barrier discharge reactor for the first time. In plasma catalytic CO2 reduction, the effects of discharge power and flow rate on T-ax, T-w, and CO2 conversion were examined. On the basis of T-ax, compared with the thermal catalytic case, the plasma catalytic case only shows a weak synergistic effect. It was confirmed that the synergistic effect is overestimated if based on T-w (except for the heat-insulated or quasi-adiabatic reactors).