Ag7Au6 Cluster as a Potential Gas Sensor for CO, HCN, and NO Detection

Abstract

Ag–Au bimetallic clusters have demonstrated extreme sensitivity, which can be theoretically explained by the conductivity change of the clusters induced by the absorption process, to molecules such as CO, H2S, and so forth. Recently, a 13-atom alloy quantum cluster (Ag7Au6) has been experimentally synthesized and characterized. Here, the adsorption of CO, HCN, and NO on the Ag7Au6 cluster was investigated using density functional theory calculations in terms of geometric, energetic, and electronic properties to exploit its potential applications as gas sensors. It is found that the CO, HCN, and NO molecules can be chemisorbed on the Ag7Au6 cluster with exothermic adsorption energy (−0.474 ∼ −1.039 eV) and can lead to finite charge transfer. The electronic properties of the Ag7Au6 cluster present dramatic changes after the adsorption of the CO, HCN, and NO molecules, especially its electric conductivity. Thus, the Ag7Au6 cluster is expected to be a promising gas sensor for CO, HCN, and NO detection.