In-situ doping nickel single atoms in two-dimensional MXenes analogue support for room temperature NO2 sensing
Weiming Chen, Peipei Li, Jia Yu, Peixin Cui, Xiaohu Yu, Weiguo Song, Changyan Cao
Abstract
MXenes are promising supports for anchoring metal single atoms due to their versatile composition, well-defined nanostructures, and suitable conductivity. However, metal single atoms are usually coordinated with surface terminal groups (-O, -OH, -Cl, etc.) of MXenes via conventional wet-impregnation, resulting in limited electronic structure modification. Through a NiCl2 molten salt etching method, we observed that Ni single atoms could be in-situ doped in the lattice of MXenes analogue TiC0.5N0.5 support (denoted as Ni1/TiC0.5N0.5), resulting in much larger charge transfer from Ni atoms to adjacent Ti atoms, and thus increasing the electronic density of these Ti atoms. When used for NO2 sensing, Ni1/TiC0.5N0.5 exhibited excellent response sensitivity (ultra-low limit of detection ∼ 10 ppb), selectivity, and good stability at room temperature. This study provides an effective strategy for producing MXenes analogue supported metal single atoms for potential application in gas sensing.