Impact on Electrodes During Plasma Decomposition of CO2

A reactor being developed and instrumented for plasma decomposition of carbon dioxide contains a pin-to-plane micro-discharge, with a stainless steel pin and aluminum electrode. The degradation of the aluminum electrode over testing time is an unwanted effect of this particular system. A predictive model of degradation of the current electrode is being developed to relate the system parameters and treatment time with degradation of the electrode. Other aspects of the set-up are also being studied based on this phenomenon, including energy losses from the system, which can detract from the overall efficiency of the process of plasma decomposition of carbon dioxide. A test electrode of aluminum is arranged with a demarcated grid of test sections. Then, plasma discharges are applied at the centers of these grids within each area of approximately 2 mm x 2mm. Scans of these areas are taken using a three-dimensional optical profiler for non-contact measurement and characterization of micro- and nano-scale features of the aluminum surface. It should be noted that the instrumentation utilized provides up to 0.15 nm vertical precision. Hence, a predictive model can be developed with the purpose of determining how long the discharge gap length can remain within a reasonable range to sustain the plasma discharge across the electrodes. Toward the goal of engineering a plasma system which can be consistently deployed to decompose carbon dioxide, considerations on longevity of the electrodes and/or necessary maintenance can be a useful step in scaling these systems and preparing them for more widespread use. Results will include impact of the micro-discharge on the electrodes during typical treatment times of plasma decomposition of carbon dioxide.