First-Principles Calculations of Gas-Sensing Properties of Pd Clusters Decorated AlNNTs to Dissolved Gases in Transformer Oil

Abstract

The potential decoration structures of Pd atom, Pd2 cluster and Pd3 cluster on the AlN nanotubes (AlNNTs) surface were initially studied. As the structure of Pd2 decoration on AlNNTs is similar to that of two single Pd atom decoration, only Pd-AlNNTs and Pd3-AlNNTs were further analyzed. It is found that Pd atom and Pd3 cluster preferred to adsorb on the surface surrounding N atom. Pd atom and Pd3 cluster reduced the energy band gap, and increases the electrical conductivity of AlNNTs, especially Pd3 decoration. The adsorption behavior, charge transfer, densities of states, projected densities of states, and molecular orbital analysis of AlNNTs towards four oil-dissolved gases, including H2, CH4, C2H2, and C2H4, were analyzed. These analyses indicated that Pd-AlNNTs and Pd3-AlNNTs showed strong interaction to four gas molecules. Pd-AlNNTs and Pd3-AlNNTs acted as the electron donators by transmitting electrons to the gas molecules during the interaction. According to the analysis of gas-sensing response, gas molecules adsorption on Pd-AlNNTs and Pd3-AlNNTs decreases the conductivity of the whole adsorption system.

Keywords

• DFT calculations
• Pd cluster decoration
• DGA
• adsorption and sensing