Directional Growth of One-Dimensional CO2 Chains on ZnO(101̅0)

Atomic insights into the interaction of CO2 with the mixed-terminated ZnO(1010) surface were achieved in detail by low-temperature scanning tunneling microscopy (LT-STM) together with density functional theory (DFT) calculations. The binding site and adsorption geometry were directly imaged by LT-STM, revealing that the CO2 molecules are chemisorbed and turned into surface carbonate species. The strong interaction of CO2 with the ZnO(1010) surface in turn activates the surface, i.e., reconstructs the local surface such that facilitates further CO2 bindings, leading to the formation of a one-dimensional assembly structure which grows along the [0001] direction. DFT simulations indicated that the superior agglomeration energies along ⟨0001⟩ directions as well as the CO2-induced surface reconstruction are responsible for the directional growth of the surface carbonate chains.