Photocatalytic reduction of CO₂ using Ti-MCM-41 photocatalysts in monoethanolamine solution for methane production

Photocatalytic reduction of carbon dioxide (CO₂) to form a valuable energy source of methane (CH₄) in monoethanolamine (MEA) solution is first investigated by mesoporous photocatalysts of Ti-MCM-41 in this study. The MEA solution was chosen as the absorbent and reductant because amine absorption is one of the most popular methods for CO₂ capture from flue gas streams. Also, it is intended to integrate the CO₂ capture and utilization into one process. The photocatalytic results of methane yields indicated that MEA served as a better reductant than water and NaOH which have been commonly used for CO₂ reduction. For the best photocatalyst of Ti-MCM-41(50) manufactured at a Si/Ti molar ratio of 50, its methane yield (62.42 Îmol/g of cat.) was much higher than that of commercial P25 photocatalyst after 8 h of UV illumination. A photoreduction quantum efficiency (PQE) of 9.18% was achieved.