Nonetheless, addressing global warming and energy scarcity issues can potentially be achieved by reducing CO 2 to hydrocarbons using solar light. Through the photoreduction of CO 2 in the presence of water and solar light, it is possible to produce substances such as CH 4 , HCOOH, CO, CH2O, CH3COOH, and CH 4 , depending on the transfer of electrons and protons. Among the promising photocatalysts, TiO 2 stands out for its potential in CO 2 reduction. The reaction pathways for CO 2 reduction using TiO2 can be depicted as follows. represents the defective surface. Specifically, blue species are adsorbed at oxygen vacancies, while black species are adsorbed on the titanium surface.