Hydrothermal Synthesis and Structural Characterization of NiO/SnO2Composites and Hydrogen Sensing Properties

Chao Wei,Fengbo Tao,Shudi Peng,Yuncai Lu,Qu Zhou,Bin Bo,Wei Song

doi:10.1155/2015/450485

Abstract

Pure SnO2and NiO doped SnO2nanostructures were successfully synthesized via a simple and environment-friendly hydrothermal method. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectra (XPS) were used to investigate the crystalline structures, surface morphologies and microstructures, and element components and their valences of the as-synthesized samples. Furthermore, planar chemical gas sensors based on the synthesized pure SnO2and NiO/SnO2composites were fabricated and their sensing performances to hydrogen, an important fault characteristic gas dissolved in power transformer oil, were investigated in detail. Gas sensing experiments indicate that the NiO/SnO2composites showed much higher gas response and lower working temperature than those of pure SnO2, which could be ascribed to the formation of p-n heterojunctions between p-type NiO and n-type SnO2. These results demonstrate that the as-synthesized NiO/SnO2composites a promising hydrogen sensing material.

Highlights

Larger oil-immersed power transformers are costly and important electrical apparatus in power supply system
The sensors fabricated from the synthesized pure SnO2 and NiO/SnO2 composites were exposed to a certain concentration of H2 gas at various working conditions to find out the optimum operating temperature
The crystalline structures, surface and morphology characteristics, and compositions and chemical states were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectra (XPS) measurement, respectively

Summary

Introduction

Larger oil-immersed power transformers are costly and important electrical apparatus in power supply system. Tang et al [15] prepared hollow hierarchical SnO2-ZnO composite nanofibers by an electrospinning method and reported the SnO2-ZnO composite nanofibers exhibited excellent methanol selectivity in the presence of ethanol, acetone, formaldehyde, ammonia, Journal of Spectroscopy toluene, and benzene at an operating temperature of 350∘C. Shen et al [17] synthesized NiOSnO2 nanofibers via electrospinning and investigated their sensing performances to ethanol with three types of sensor structures. To the best of our knowledge, reports on the synthesis of p-NiO/n-SnO2 composites through a simple and environment-friendly hydrothermal method and researches on their sensing properties for recognition of dissolved H2 in transformer oil have been rare. In this study, we present sensitive H2 sensors fabricated from p-NiO and nSnO2 nanostructures and measure their gas sensing performances toward H2. We interestingly find that the NiO/SnO2 composites sensor exhibits excellent H2 sensing properties in comparison to the pure SnO2 based sensor

Experimental

Results and Discussion

Conclusion