In-situ doping nickel single atoms in two-dimensional MXenes analogue support for room temperature NO_(2) sensing

摘要

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 TiC_(0.5)N_(0.5) 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 NO_(2) sensing,Ni_(1)/TiC_(0.5)N_(0.5) 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.