Hydrogenation of carbon dioxide to methanol with a discharge-activated catalyst

To mitigate greenhouse gas CO2 emissions and recycle its carbon source, one possible approach would be to separate CO2 from the flue gases of power plants and to convert it to a liquid fuel, e.g., methanol. Hydrogenation of CO2 to methanol is investigated in a dielectric-barrier discharge (DBD) with and without the presence of a catalyst. Comparison of experiments shows that this nonequilibrium discharge can effectively lower the temperature range of optimum catalyst performance. The simultaneous presence of the discharge shifts the temperature region of maximum catalyst activity from 220 to 100 degrees C, a much more desirable temperature range. The presence of the catalyst, on the other hand, increases the methanol yield and selectivity by more than a factor of 10 in the discharge. Experiment and numerical simulation show that methane formation is the major competitive reaction for methanol formation in the discharge. In the case of low electric power and high pressure, methanol formation can surpass methanation in the process.