Janus WSSe monolayer adsorbed with transition-metal atoms (Fe, Co and Ni): excellent performance for gas sensing and CO catalytic oxidation

The adsorption behaviors of Janus WSSe monolayer for transition-metal (TM) Fe, Co and Ni atoms, gas sensing mechanism of Ni-WSSe monolayer for harmful gas molecules CO, NH3 and H2S, and catalytic performance of Fe-WSSe monolayer for CO oxidation are explored by the first-principles methods. The adsorption strength, stability and band gap exhibit the increasing rule with TM atomic order, i.e., Fe-WSSe < Co-WSSe < Ni-WSSe. The adsorption property of Ni-WSSe monolayer for these harmful gas molecules changes from physisorption into chemisorption with the most prominent adsorption capacity for CO molecule. The CO catalytic oxidation on Fe-WSSe monolayer would be more likely to cyclically occur at room temperature by ER mechanism, with potentially high reactive speed and efficiency. The Fe-WSSe and Ni-WSSe systems may act as the potential single-atom catalyst (SAC) for CO oxidation and gas sensor for these harmful gas molecules, respectively. Thus, the electronic structure, gas sensing performance and catalytic activity of Janus WSSe monolayer could be regulated by the adsorption of TM atoms.