2D WS2-edge functionalized multi-channel carbon nanofibers: effect of WS2 edge-abundant structure on room temperature NO2 sensing

Abstract

Transition metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂), have been studied intensively in recent years due to wide range of potential applications. TMD gas sensors have been developed and intensively explored for their promising applications. In recent times, it has been reported that edge sites of TMDs can contribute to highly enhanced gas adsorption properties. Herein, superior room temperature gas sensing properties of WS₂ edge functionalized carbon nanofibers (CNFs) with multiple tubular pores (WS₂@MTCNFs) have been demonstrated. A copolymer-electrospinning route, which uses poly(styrene-acrylonitrile) as sacrificial templates and WS₂ precursor containing poly(acrylonitrile) as carbon matrix, offered facile synthesis of CNFs having high gas permeability with single-layered WS₂ edge-rich surface. As a result, WS₂@MTCNFs based sensors exhibited notable gas response (15% at 1 ppm of NO₂) at room temperature compared to pristine CNFs (2% at 1 ppm of NO₂), which can be attributed to the synergistic effects that originated from enhanced surface area and open porosity with numerous elongated pore channels of MTCNFs as well as remarkably increased active spots on the surface from WS₂ edge sites.