Nanomaterials, characterized by their nanoscale dimensions and high surface area, offer several advantages for photocatalytic CO 2 reduction. One key advantage is their efficient light absorption, facilitated by their tunable band gaps and quantum confinement effects. This enables nanomaterials to effectively utilize a broad range of the solar spectrum, including visible light, for photocatalytic reactions. Quantum dots, semiconductor nanoparticles, and metal oxides are among the commonly studied nanomaterials in this field. Quantum dots, semiconductor nanoparticles with unique quantum confinement pro perties, exhibit high extinction coefficients for visible light, making them efficient photosensitizers. Their small size and large surface area provide abundant active sites for CO 2 adsorption and catalytic reactions.