Large-scale synthesis of ultra-long sodium doped MoS2 nanotubes with high electrocatalytic activity

Abstract

Large-scale production of high-quality molybdenum disulfide (MoS2) nanotubes is important due to their special structure and inherent properties. In this paper, we reported a low-cost approach to synthesize ultra-long Na doped MoS2 nanotubes on a large-scale by sulfurizing the precursors which produced by a hydrothermal method. Sodium chloride (NaCl) and ammonium molybdate solution are stirring in a heated water bath to prepare these precursors. Then Na doped MoS2 nanotubes are obtained by vapor-phase sulfurization using sulfur powder as S source. Transmission electron microscopy (TEM) images, X-ray diffraction (XRD) pattern, Raman spectra and X-ray photoelectron spectroscopy (XPS) prove the crystal structure of Na doped MoS2 with elemental composition of NaxMoS2 (x = 0.38–0.44). The morphology of the samples shows pure high-quality Na doped MoS2 nanotubes with length ranging from 100 to 300 µm. When used as the counter electrode (CE) of dye-sensitized solar cells (DSSCs), these nanotubes have excellent electrocatalytic activity. A power conversion efficiency of 5.85% is recorded in these solar cells, which is near that of the referenced Pt counter electrodes. This makes these nanotubes are ideal CEs of DSSCs. So this method is a simple and convenient approach to synthesize transition metal dichalcogenides (TMDs) nanotubes on a large scale.