Review of plasma catalysis on hydrocarbon reforming for hydrogen production-Interaction, integration, and prospects

This paper, for the first time, reviews the development of the application of plasma catalysis, the combination of plasma and thermal catalysis, on hydrocarbon reforming for H₂ generation. It has been experimentally demonstrated that this novel technique results in a synergistic effect, i.e., the performance achieved with plasma catalysis is better than the summation of plasma-alone and catalysis-alone, indicating its promising application on H₂ generation. To gain better insights and provide useful information for further optimization, the interactions between plasma and thermal catalysis possibly leading to the synergism observed in different plasma catalysis systems are comprehensively reviewed. The thermal and non-thermal plasmas are suggested as the suitable plasma source driving the two-stage and single-stage plasma catalysis systems, in which catalyst are located downstream and inside the plasma reactor, respectively. In the latter case, the non-thermal plasma should play the role as exciting the reactants to vibrational state instead of converting them. Because of the either too high reduced field or too low electron density to effectively generate vibrationally excited species in the existing non-thermal plasmas, a novel power supply, which could separately control the electron density and electron energy is proposed to serve as the ideal plasma source.