Metal-doped Photocatalysts to Reduce Carbon Dioxide in Ethanolamine Solution for Methane Production

摘要

Photocatalytic reduction of carbon dioxide (CO_2) to form valuable energy source of methane (CH_4) in the ethanolamine (MEA) solution is investigated in this study. The TiO_2 photocatalysts were prepared by doping with nano-sized metals (Fe, Zn, Mn, Ce) via the co-precipitation method. The photocatalytic reduction process was performed in the MEA solution because the MEA absorption is one of the most popular methods for CO_2 greenhouse gas capture from flue gas streams. And it is intended to integrate the CO_2 capture and utilization into one process. The tests were performed with the UV light source of 9W and 365 nm. The light intensity of 6.3 mW/cm~2 was measured at the center point between the UV light source and the outer glass of the reactor. The 5 hours test results showed the methane yield followed the order of Ce-TiO_2 > Mn-TiO_2> Zn-TiO_2 > Fe-TiO_2. Tests were also evaluated with a solar light concentrator, and it has been proved that it is possible to produce CH_4 under solar light without the addition of any external energy source.