Nano rod-shaped ZnO provides a high

Nano rod-shaped ZnO provides a high surface area and more sites for CO2 adsorption, forming a multi-layer structure with CuO. The low degree of lattice mismatch between ZnO and CuO is conducive to the formation of P-N heterojunctions. The high electronegativity and alkalinity of the two reduce the activation energy required for the reaction, which is also one of the important reasons for achieving CO2 detection at room temperature. Secondly, the work function of copper oxide is higher than that of zinc oxide, Beneficial for electron transfer from copper oxide to zinc oxide. In the air, oxygen molecules interact with the surface electrons of layered ZnO/CuO/RGO nanomaterials and convert them into ionized oxygen (O2- or O-) sites. When carbon dioxide gas passes through layered ZnO/CuO/RGO nanomaterials, it adsorbs CO2 molecules and combines with surface O2- or O- to form carbonate ions. The adsorbed molecules begin to increase and reach saturation, and the chemical reaction is as follows.