Metal-decorated siligene as work function type sensor for NH₃ detection: A DFT approach

In this work, we employed density functional theory calculations to investigate the feasibility of X-decorated (X = Li, Na, K, Mg, Ca, Sc, Ti, and Pd) two-dimensional siligene (2D SiGe) for ammonia (NH₃) sensing through variations of its work function. The results indicated that NH₃ molecule is physisorbed on pristine 2D SiGe. Moreover, Li, Na, K, Sc, Ti, Pd and Ca atoms are chemisorbed on the 2D SiGe, while Mg is barely adsorbed. Likewise, NH₃ tends to be adsorbed on the metal atoms of the decorated 2D SiGe with adsorption energies between −0.13 eV and−1.47 eV. The changes observed in the work functions of Na-, Mg-, Ca-, Sc-, and Pd-decorated 2D SiGe upon NH₃ may allow its detection. Moreover, the results indicate that only the recovery times of 2D SiGe decorate with Na, K, Ca and Pd atoms could allow for their use as reusable sensors of NH₃, while 2D SiGe decorated with Li, Mg, Sc and Ti could be used to trap NH₃. From the results of work functions and recovery times on metal decorated 2D SiGe, it is concluded that Pd, Ca, and Na-decorated 2D SiGe are the most suitable material for sensing NH₃ molecules.