Adsorption of CF3SO2F decomposition products by HfS2 vacancy structures as a promising detection device: A DFT study

Abstract

As a new environmentally friendly insulating gas that is expected to replace SF6, CF3SO2F has great potential for application in the power industry. However, the harm caused by its decomposition products cannot be ignored, and gas sensing detection technology is an effective means to solve this problem. The adsorption properties of HfS2 monolayer, Hf vacancy (HfS2-HfV) and S vacancy (HfS2-SV) for four CF3SO2F decomposition products (HF, SO2, SO2F2 and CF4) were investigated based on density functional theory. The results show that S vacancy is easier to form than Hf vacancy, and S vacancy can also significantly enhance the adsorption effect of HfS2 on the four gases, among which the adsorption effect of SO2 is the most obvious improvement, with the adsorption energy of -2.695 eV. During the adsorption process, SO2 acts as an electron acceptor and gains electrons, while the other three gases act as electron donors and lose electrons. After the adsorption of four gases, HfS2-SV with a large change of work function indicates that HfS2-SV has the potential to be used as a FET gas sensor. In addition, at the temperature of 298 K, HfS2-SV has an extremely ideal recovery time for SO2F2 and a very long recovery time for SO2, indicating that HfS2-SV has the potential to detect SO2F2 or remove SO2 by purposeful modification the S vacancy on the surface of HfS2 through defect engineering technology. This study shows that HfS2-SV is a promising new gas detection material or adsorption material for the detection and removal of CF3SO2F decomposition products.