Temperature Dependence of Sensors Based on Silver-Decorated Nitrogen-Doped Multiwalled Carbon Nanotubes

Figure 6

Adsorption of CS₂ on Ag₅₅C₈₀ cluster. (a) Initial geometry consisting in an icosahedral Ag₅₅ cluster surrounded by a carbon layer (C₈₀). (b) Relaxed structure of Ag₅₅C₈₀ cluster. (c) shows the relaxed structure after the exposure of seven CS₂ molecules at  K; in this case, only two CS₂ molecules are covalently attached to the Ag₅₅C₈₀ cluster. (d) and (e) depict the final structures obtained by molecular dynamical simulations at and 350 K, respectively, during 1 ps. In (a) only two CS₂ molecules are covalently attached to the cluster, whereas in (e) five CS₂ molecules are covalently attached to the Ag₅₅C₈₀ cluster, suggesting that it is possible to obtain a chemisorption state at higher temperatures. These results could explain the sensor behavior when the temperature is increased. Note that the CS₂ molecules are bound to the cluster via the sulfur atoms and low-coordinated Ag atoms.