The continual and increasing use of fossil fuels throughout the world has advanced concerns of atmospheric carbon dioxide (CO 2 ) concentrations, causing a swell of scientific interest to ease the predicted effects of global warming. This work experimentally investigates the conversion of CO 2 to carbon monoxide (CO) and oxygen in an atmospheric pressure microwave plasma/catalyst system. Diagnostics such as mass spectrometry and optical emission spectroscopy are used to identify the gas species present after plasma treatment and to measure plasma temperatures. The CO 2 gas is first treated with plasma alone, and is then treated with a combination of plasma and rhodium (Rh) catalyst material. While the plasma system alone is able to achieve a 20% energy efficiency, the Rh catalyst actually causes a drop in efficiency due to reverse reactions occurring on the surface. The plasma temperature measurements indicate thermal equilibrium between T r and T v around 6000-7000 K.

One possible solution to mitigating the effects of high atmospheric concentrations of carbon dioxide (CO 2 ) is the use of a plasma source to break apart the molecule into carbon monoxide (CO) and oxygen. This work experimentally investigates the efficiency of dissociation of CO 2 in a 1-kW radio-frequency (rf) plasma source operating at 13.56-MHz in a low-pressure discharge. Mass spectrometry diagnostics are used to determine the species present in the discharge, and these measurements are used to calculate the energy efficiency and conversion efficiency of CO 2 dissociation in the rf plasma source. Experimental results have found that the conversion efficiency of CO 2 to CO can reach values near 90%, however energy efficiency reaches a maximum of 3%. A theoretical energy cost analysis is also given as a method to evaluate the effectiveness of any plasma system designed for CO 2 emissions reduction.

In recent years, carbon dioxide (CO 2 ) plasma discharges have gained considerable interest due to rising concerns of global climate change. The increasing dependence on fossil fuels to serve as the world's primary energy source has lead to nontrivial effects on the overall CO 2 content in the atmosphere. One possible solution to mitigating the effects of high atmospheric concentrations of CO 2 is the use of a plasma source to break apart the molecule into carbon monoxide (CO) and oxygen.The CO can be filtered out for use in the chemical industry and as a fuel in industrial applications, or CO can be further dissociated to produce carbon and oxygen.This work experimentally investigates the dissociation of CO 2 and CO in a 1 kW radio frequency plasma source operating at 13.56 MHz in the low pressure regime of about 100-300 mTorr. Mass spectrometry, optical emission spectroscopy, and x-ray photoelectron spectroscopy diagnostics are used to determine the species present in the discharge. For plasmaassisted CO 2 dissociation to be a practical and cost-effective solution for the climate change challenges, the process must meet certain standards of energy efficiency. Therefore the energy efficiency of the radio frequency plasma source is examined for both CO 2 and CO dissociation, and is determined too low for large-scale industrial applications. Improvements must be made to enhance the energy deposition into specific modes of dissociation through changing the type of plasma source and/or adding a catalyst into the system to increase the rate of dissociative reactions.