Ce–Ag Active Bimetallic Pairs in Two-Dimensional SnS₂ for Enhancing NO₂ Sensing

Abstract

Developing gas sensors capable of efficiently detecting harmful gases is urgent to protect the human environment. Here, an active Ce-Ag bimetallic pair was innovatively introduced into SnS₂, which successfully exhibited excellent NO₂ gas sensing performance. 0.8% Ce-SnS₂-Ag showed a gas sensing response of 5.18 to 1 ppm of NO₂ at a low temperature of 80 °C, with a lower limit of detection as low as 100 ppb. DFT calculations revealed that Ce atoms are substituted into the main lattice of SnS₂, which opens up the interlayer spacing and serves as an anchor point to fix the Ag atoms in the interlayer. The Ce-Ag bimetallic pairs successfully modulate the electronic structure of SnS₂, which promotes the adsorption and charge transfer between NO₂ and Ce-SnS₂-Ag and thus achieves such an outstanding gas sensing performance. This work opens an avenue for the rational functional modification of SnS₂ with an optimized electronic structure and enhanced gas sensing.