Embedding of ultra-dispersed MoS2 nanosheets in N,O heteroatom-modified carbon nanofibers for improved adsorption of Hg2+

Abstract

Due to the severe stack tendency of MoS2 layers during the synthesis processes, it is still a challenge to obtain abundant single layered MoS2 on a large scale by a simple method. Molybdenum disulfide (MoS2) nanosheets embedded in carbon nanofibers (CNF) were fabricated through an electrospinning route followed by carbonization employing polyvinylpyrrolidone (or polyacrylonitrile) as carbon sources. Experimental results indicate that single layered MoS2 nanosheets uniformly dispersed in the nanocomposite fibers were synthesized by using polyvinylpyrrolidone as carbon precursor. X-ray photoelectron spectroscopy and density functional theory calculation results reveal that the strong interactions between Mo and N@O atoms suppress the stack of MoS2 nanosheets and realize the ultra-dispersed single layered MoS2 nanosheets in the nanocomposite fibers. Furthermore, the removing performances of Hg2+ from water of the synthesized MoS2/CNF nanofibers were investigated. The adsorption experiment demonstrates that single layered MoS2 nanosheets in MoS2/CNF nanofibers could provide more adsorption sites for the binding and removal of Hg2+, which are highly efficient for the removal of Hg2+ from water with an adsorption capacity of 553.8 mg/g. Moreover, the adsorption capacity of the MoS2/CNF nanofibers towards Hg2+ still kept more than 95% after 10 cycles.