Study of formaldehyde adsorption on silicene with point defects by DFT method

Abstract

To explore the chemical activity and sorption capacity of silicene with point defects for formaldehyde (HCHO), interactions between HCHO and silicene were investigated using density functional theory (DFT) calculations. As compared to the weak adsorption on perfect silicene, HCHO molecules tend to be chemisorbed onto the Si–Si bonds of defective silicene with appreciable adsorption energy. The electronic conductance changes markedly with the adsorption of HCHO molecules on silicene containing Stone–Wales (SW) defects, whereas silicene with double vacancies still exhibits indirect semiconductor characteristics after HCHO adsorption. Moreover, the adsorption energy of HCHO on silicene with SW defects (SW-Si) undergoes a continuous increase under a tensile strain up to 10%, suggesting that the chemical reactivity of an SW-Si sheet increases by applying an external strain.