NH3 capture and detection by metal-decorated germanene: a DFT study

We report an investigation of the adsorption of ammonia (NH3) on pristine, alkali (Li, Na, K), alkaline earth (Mg, Ca), and transition metal (Sc, Pd, and Ag) decorated germanene using a first-principles approach based on density-functional theory (DFT). The most stable adsorption geometries, adsorption energies, and charge transfers of NH3 adsorbed on pristine and metal-decorated germanene are thoroughly discussed. First, the NH3 adsorption on pristine germanene was considered, and subsequently, the NH3 adsorption on metal-decorated germanene was studied. Our calculations found that the NH3 is weakly adsorbed on pristine germanene. All metals improved the adsorption properties of pristine germanene. In particular, Sc, Mg, and Li atoms showed significantly enhanced interactions between NH3 and germanene. In general, the electronic and adsorption properties demonstrated that metal-decorated germanene is superior to pristine germanene for the adsorption of NH3 molecules. Changes in the work function due to adsorption of NH3 molecule on the metal-decorated germanene were also calculated. Adsorption energy and desorption time results show that Sc-decorated germanene could trap this dangerous molecule at room temperature.Graphical abstract