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

Abstract

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 NO 2 sensor based on rare-earth Nd doped VS 2 /carbon nanofibers (CNFs) (abbreviated as x%Nd-VS 2 -C), which exhibits a fast response/recovery and intense response at RT. The impact of the Nd doping amount on the NO 2 -sensing properties of x%Nd-VS 2 -C was systematically explored. The active Nd-doping and abundant S vacancies could activate the inert basal planes of VS 2 efficiently and increase the active sites of the surface, thereby improving the NO 2 -sensing performance of the sensor. Additionally, theoretical calculations validate the finding by demonstrating a more negative NO 2 adsorption energy of −3.12 eV on the (001) surface of Nd-VS 2 -C compared to −1.26 eV on pure VS 2 . The 2% Nd-VS 2 -C exhibits optimal RT NO 2 -sensing properties, with a thrilling response/recovery rate (∼17 s/20 s), high sensitivity (∼3.03 to 10 ppm of NO 2 ), favorable selectivity and stability, and low detection limit (18 ppb). The outstanding "'4S'" features make the 2%Nd-VS 2 -C sensor greatly attractive for precise and ultrasensitive NO 2 detection at RT.