This work aims to efficiently capture CO 2 on two-dimensional (2D) nanostructures for effective cleaning of our atmosphere and purification of exhausts coming from fuel engines. Here, we have performed extensive first principles calculations based on density functional theory (DFT) to investigate the interaction of CO 2 on a recently synthesized ZnO monolayer (ZnO-ML) in its pure, defected and functionalized form. A series of rigorous calculations yielded the most preferential binding configurations of the CO 2 gas molecule on a ZnO-ML. It is observed that the substitution of one oxygen atom with boron, carbon and nitrogen on the ZnO monolayer resulted into enhanced CO 2 adsorption. Our calculations show an enriched adsorption of CO 2 on the ZnO-ML when substituting with foreign atoms like B, C and N. The improved adsorption energy of CO 2 on ZnO suggests the ZnO-ML could be a promising candidate for future CO 2 capture.