Synthesis and Characterization of Nano-Tungsten Oxide Precipitated onto Natural Inorganic Clay for Humidity-Sensing Applications

Ahmed Afify,Mohamed Hassan,Azhar Hussain,Amr Mohamed,Mohamed Ataalla,Ahmad Abu-Khadra,Ahmed Elsayed,Jean-Marc Tulliani

doi:10.3390/ceramics1010010

Abstract

A wet chemical method was used to obtain tungsten oxide nanoparticles from tungsten tetrachloride and natural microfibrous inorganic clay (sepiolite) as a starting material. Precipitation of tungsten oxide species onto sepiolite under basic conditions and subsequent thermal treatment was investigated, prompted by the abundance of sepiolite in nature and the useful environmental applications that could be attained. Laser granulometry, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HR-TEM) techniques were used to study the particle-size distribution, the morphology, and the composition of the prepared sample. Our findings show the presence of tungsten oxide nanoparticles, which are less than 50 nm, on the needles of the modified sepiolite.

Highlights

Over the last decades, nanotechnologies have received great attention because they allow the synthesis of one-dimensional structures, including nanorods, nanobelts, and nanowires, which play crucial roles in the relationship between size, morphology, and featured characteristics of the powder.Transition metals and metal oxides are interesting functional materials for growing nanoparticles with a specific shape
It can be seen that the tungsten-modified sepiolite treated at 550 °C for 1 h has a narrower
It can be seen that the tungsten-modified sepiolite treated at 550 ◦ C for 1 h has a narrower particle-size distribution than pure sepiolite

Summary

Introduction

Transition metals and metal oxides are interesting functional materials for growing nanoparticles with a specific shape. They are widely used in many applications, such as sensors, catalysts, ceramics, solar cells, electrical devices, etc. Tungsten oxide is a very important semiconductor among transition metal oxides group due to its wide use of applications, such as in gas sensors [3,4], catalysts [5], photochemistry [6], and electrochromic devices [7]. Its structural units are composed of two tetrahedral silica sheets and a discontinuous central layer of octahedral magnesium oxide. This structure provides for the possibility of forming open channels with dimensions of 0.36 × 1.06 nm

Methods

Results

Conclusion