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

Abstract

Photocatalytic reduction of carbon dioxide (CO2) to form valuable energy source of methane (CH4) in the ethanolamine (MEA) solution is investigated in this study. The TiO2 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 CO2 greenhouse gas capture from flue gas streams. And it is intended to integrate the CO2 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-TiO2 > Mn-TiO2> Zn-TiO2 > Fe-TiO2. Tests were also evaluated with a solar light concentrator, and it has been proved that it is possible to produce CH4 under solar light without the addition of any external energy source.