Room Temperature Ultrasensitive NO2 Detection by Activating VS2 Basal Planes in Rare-Earth Nd-Doped VS2/Carbon Nanofibers

Two-dimensional (2D) transition metal dichalcogenides (TMDs) room temperature (RT) gas sensors are of great value for monitoring leaks of hazardous gases under harsh environments. However, the highly sensitive and rapid detection of TMDs in an energy-efficient state is still a formidable obstacle. This work reports the ultrasensitive NO₂ sensor based on rare-earth Nd doped VS₂/carbon nanofibers (CNFs) (abbreviated as x%Nd-VS₂-C), which exhibits a fast response/recovery and intense response at RT. The impact of the Nd doping amount on the NO₂-sensing properties of x%Nd-VS₂-C was systematically explored. The active Nd-doping and abundant S vacancies could activate the inert basal planes of VS₂ efficiently and increase the active sites of the surface, thereby improving the NO₂-sensing performance of the sensor. Additionally, theoretical calculations validate the finding by demonstrating a more negative NO₂ adsorption energy of −3.12 eV on the (001) surface of Nd-VS₂-C compared to −1.26 eV on pure VS₂. The 2% Nd-VS₂-C exhibits optimal RT NO₂-sensing properties, with a thrilling response/recovery rate (∼17 s/20 s), high sensitivity (∼3.03 to 10 ppm of NO₂), favorable selectivity and stability, and low detection limit (18 ppb). The outstanding “‘4S’” features make the 2%Nd-VS₂-C sensor greatly attractive for precise and ultrasensitive NO₂ detection at RT.