Porous Au-embedded WO3 Nanowire Structure for Efficient Detection of CH4 and H2S.

Nguyen Minh Vuong,Dojin Kim,Hyojin Kim

doi:10.1038/srep11040

Abstract

We developed a facile method to fabricate highly porous Au-embedded WO3 nanowire structures for efficient sensing of CH4 and H2S gases. Highly porous single-wall carbon nanotubes were used as template to fabricate WO3 nanowire structures with high porosity. Gold nanoparticles were decorated on the tungsten nanowires by dipping in HAuCl4 solution, followed by oxidation. The surface morphology, structure, and electrical properties of the fabricated WO3 and Au-embedded WO3 nanowire structures were examined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and current–voltage measurements. Formation of a nanowire structure resulted in significant enhancement in sensing response to H2S and CH4 gases. Furthermore, Au embedment into the WO3 nanowire structures remarkably improved the performance of the sensors. The increase in response performance of sensors and adsorption–desorption kinetic processes on the sensing layers were discussed in relation with the role of Au embedment.

Highlights

We developed a facile method to fabricate highly porous Au-embedded WO3 nanowire structures for efficient sensing of CH4 and H2S gases
The HR-transmission electron microscopy (TEM) images revealed a high crystallinity of the synthesized WO3 nanowires and gold particles
The images were obtained by scanning TEM (STEM)–energy-dispersive X-ray (EDX) spectroscopy, which suggest that gold atoms form nanoparticles on the WO3 nanowire surface, and diffuse inside of the WO3 crystalline lattice

Summary

Introduction

We developed a facile method to fabricate highly porous Au-embedded WO3 nanowire structures for efficient sensing of CH4 and H2S gases. The response of a sensor, can be controlled by modifying the properties of sensing layer, including grain size, porosity, thickness, morphology, and impurities, by surface modification with novel metals[2]. Metal nanoparticle decoration and doping of WO3 nanostructures have been widely studied, and the modified materials showed desirable properties, thereby improving the performance of devices. Pt and Pd nanoparticles enhance the dissociation of H2 molecules on WO3 surface via the known spillover effect, thereby improving the performance of H2 gas sensor and gaschromic devices[10,11]. The high-porosity nanowire structures of Au-embedded WO3were synthesized by using porous single-wall carbon nanotubes (SWCNTs) as template, followed by tungsten deposition, dip coating in gold salt solution, and oxidation. The adsorption–desorption kinetic processes on the surface of Au nanoparticles and WO3 nanowires surface were discussed

Methods

Results

Conclusion