Triethanolamine (TEA) aqueous solution as an Electrolyte promoter in CO 2 photoelectro-conversion under simulated solar irradiation assisted by Cu-doped graphene-Titania Catalyst Md. Rakibul Hasan a , Sharifah Bee Binti O. A. Abdul Hamid b,* , Wan Jeffrey Basirun c Nanotechnology & Catalysis Research Centre (NANOCAT), 3rd Floor, Block A, Institute of Postgraduate Studies (IPS) building, University of Malaya, 50603 Kuala Lumpur, Malaysia. a rakibhhc130022@siswa.um.edu.my, b sharifahbee@um.edu.my, jeff@um.edu.my c *corresponding author: sharifahbee@um.edu.my Keywords: TEA, carbon dioxide, photoelectrocatalysis, graphene-titania composite, solar simulator. Abstract Copper doped graphene-TiO 2 nanocomposite were prepared via sol-gel process and embedded onto ITO coated glass films using electrophoretic deposition technique. The catalyst films were used for photoelectrocatalysis (PEC) of CO 2 induced under simulated solar irradiation. Triethanolamine (TEA) aqueous solution was used as an electrolyte in this experiment. CO 2 capture in the electrolyte solution plays vital role in the PEC process and in this case, the effect of TEA was investigated. Although the absorption rate of CO 2 is lower in TEA solution than primary or secondary amines, CO 2 loading was found higher in the solution. Less reactivity of TEA towards CO 2 was also observed. The impedance results showed that, increased concentration of TEA in aqueous solution helps to reduce charge transfer resistance and thus facilitates CO 2 reduction process.