Adsorption and sensing of CO on VS2 monolayer decorated with transition metals (Cr, Mn, Fe, Co, Ni): A first-principles study

The adsorption behavior of transition metal (TM = Cr, Mn, Fe, Co, and Ni) atoms in VS2 monolayer, and the gas-sensing mechanism of CO in (Cr, Mn, Fe, Co, and Ni)-VS2 monolayer were studied using density functional theory. The results show that the band structures of Cr-, Mn-, Fe-, Co-, Ni-VS2 systems maintain metallic properties. Interestingly, through the analysis of charge transfer and adsorption energies, the (CO adsorption on VS2) CO/VS2 system exhibited physical absorption, while the (CO adsorption on TM-VS2) CO/TM-VS2 system exhibited chemisorption. The results show that there is a strong interaction between TMs-VS2 and CO, and a covalent bond is formed between CO and TMs. In addition, the band structures of CO/(Cr-, Mn-, Fe-, Co-, Ni-VS2) systems also maintain metallic properties. At the same time, the appropriate adsorption energy and short recovery time at high temperature indicate that Mn-, Fe-VS2 monolayers have high selectivity and sensitivity and good reversibility, and are promising CO sensor.