SnAu clusters as detectors of CO and NO gases: A DFT study

Abstract

Monitoring and control of CO and NO gases are now considered important for public health. These can be achieved by the research and development of novel sensors. Bimetallic Au–Me clusters such as Au-Pt, Au-Pd, and Au-Pb exhibit extremely high sensitivity, making them suitable for application in gas adsorption and sensing. Here, the ground-state structure, average binding energy, fragmentation energy, second-order energy difference, HOMO–LUMO gap, and average charge of SnnAun (n: 2–12) clusters were evaluated using density functional theory calculations. It was found that the SnnAun (n = 3, 8) clusters exhibited optimal performance in terms of chemical stability and charge transfer dynamics. Furthermore, the efficiency of CO and NO adsorption on the SnnAun (n = 3, 8) clusters was investigated in terms of the geometric, energetic, and electronic properties of the clusters. The results showed that CO and NO molecules chemisorb on the SnnAun (n = 3, 8) clusters, thereby allowing limited charge transfer, which significantly affects the physical properties and HOMO–LUMO gap of CO and NO molecules. These results suggest that the SnnAun (n = 3, 8) clusters can act as gas adsorbents for CO and NO molecules, and also can be used as effective sensors for NO detection.