Application of microwave plasma technology to convert carbon dioxide (CO₂) into high value products: A review

The most important challenge faced by mankind in the 21st century is the global warming issues associated with the global energy demand. A sustainable and low carbon-based energy economy must be developed to reduce the dependency on non-renewable fossil fuels. Other than exploring renewable energy technology, such as solar, hydro, and wind, recycling and utilization of carbon dioxide (CO₂) in synthesizing of high value-added products is also an alternative solution to mitigate climate change. As a potential technology, the plasma-based decomposition of CO₂ has received a lot of interest, especially microwave discharge due to its outstanding ability to produce non-equilibrium plasma with high ionization power, to convert CO₂ in an energy-efficient manner, and others. Hence, this paper is written to provide an overview of the microwave plasma technology on CO₂ conversion. The basic theory of plasma technology has also been discussed to brief the readers, particularly the non-specialist, on the technical background. The parameters that affect the performance of the CO₂ conversion process under microwave discharge such as pressure, microwave power supply, gas flow rate/pattern, co-reactant, and catalyst, are also highlighted. To sum up, the prospects and challenges for the commercialization of CO₂ utilization, such as methane(CH₄) with CO₂ reforming in syngas production, using microwave plasma technology have also been emphasized.