Adsorption of CO2, H2O, H2S, NH3 and NO2 on germanane nanosheet—A density functional study

Abstract

In this research work, adopting density functional theory method, the structural stability including electronic properties and adsorption behavior of various toxic small gases namely CO2, H2S, NH3 and NO2 molecules on the germanane nanosheets are explored. The adsorption behavior of H2O on germanane nanosheet is also studied to find the influence of humidity effect on sensing response. To ensure the stability of the germanane nanosheets, the formation energy is computed first, and its value is calculated as negative formation energy (−2.18 eV) eV/atom. Then, using energy band gap, adsorption energy, Bader charge transfer and a modification in band gap, the reaction between the main substance germanane nanosheets and gases are investigated. For pure germanane nanosheet the energy gap is calculated to be 1.508 eV. The energy band gap of germanane nanosheets changes according to the adsorption of H2O, CO2, H2S, NO2 and NH3 gases. The outcome of this study indicates that germanane nanosheets could be utilized as an effective gas sensing material for NO2.