| AVS 63rd International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS-ThA |
| Session: | Plasma Chemistry and Plasma Surface Interactions |
| Presenter: | Tomohiro Nozaki, Tokyo Institute of Technology, Japan |
| Correspondent: | Click to Email |
Renewable energy is recognized as indispensable CO2-free energy source in our future society and tremendous increase in renewable energy has been demanded worldwide. However, it is also well-known that energy generation and timing strongly fluctuate depending on the climate and geological conditions. Energy storage by secondary batteries and smart grid concept have been investigated extensively by now. More recently, power to gas (PtG) concept is highlighted. The key component of PtG is the electrochemical conversion of H2O into H2 and O2 with renewable electricity, enabling direct conversion of electrical energy to chemical energy. Basic concept of PtG can be extended to the synthetic CH4 production from CO2 and renewable hydrogen for increased energy storagibility and transportability. The key strategy is that electrochemical H2O conversion and conventional C1 chemistry, which utilizes thermal energy at various temperature range, is combined appropriately in order to maximize overall electrical to chemical conversion processes.
In this study, nonthermal plasma enhanced catalytic conversion of CH4 and CO2 into syngas (CO and H2) is presented. Electrical energy is converted into chemical energy of syngas via nonthermal plasma (electrical energy) driven endothermic reaction. Syngas is then converted into not only CH4, but also carbon containing liquid fuels with the existing C1 chemistry. Liquid hydrocarbon would be more preferable than synthetic CH4 because transport and storage capability of liquid hydrocarbons is improved with great flexibilities. CH4 and CO2 reforming is known as dry methane reforming (DMR): CO2 can be oxidizer as well as carbon source for C1 chemistry. There are two major problems in DMR: one is coke formation which readily deteriorates catalyst activity. The other is high temperature thermal energy is needed (above 800 °C). Therefore, combustion of initial feed is unavoidable. Nonthermal plasma enables low temperature conversion of CH4 and CO2 at relatively low temperature (below 600 °C), yet fast reforming is guaranteed because plasma-generated reactive species promote catalytic surface reaction. We have developed pulsed dry methane reforming as comprehensive diagnostic method of plasma catalytic methane reforming [1]. This diagnostic method is further enhanced by the combination of optical emission spectroscopy, isotope labeling, and admixture of reaction promoters. In the symposium, mechanistic study of plasma catalysis and prospects for practical application (PtG) will be presented.
[1] S. Kameshima, K. Tamura, Y. Ishibashi, T. Nozaki, Catalysis Today, 256 (2015) 67-75.