Improving Hydrogen Sensing Performance of TiO2 Nanotube Arrays by ZnO Modification

Aihua Yu,Jianxin Yi,Haitao Xun

doi:10.3389/fmats.2019.00070

Aihua Yu, Jianxin Yi + Show 1 more

Open Access

https://doi.org/10.3389/fmats.2019.00070

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Abstract

In this work, anodization was utilized to synthesize highly ordered TiO2 nanotube arrays, and ZnO was successfully decorated onto the surface of as-prepared TiO2 nanotubes via a facile impregnation method. The gas sensing performance of TiO2@ZnO composite was systematically studied. At a working temperature of 300 °C, the response of TiO2@ZnO to 100 ppm H2 was ~340, 2.7 times larger than that of pristine TiO2. A power-law relationship between the response and H2 concentration was observed. In addition, the response time was significantly reduced by four times, and improved selectivity to H2 was achieved. The highly improved sensing performance of TiO2 nanotubes by ZnO decoration may be attributed to the enhanced oxygen adsorption and formation of n-n heterojunctions.

Highlights

Hydrogen is widely used as an important energy carrier and chemical material
Hydrogen Gas Sensing ordered nanotubes with nanoparticles of non-noble metal, i.e., SnO2, both the sensitivity and response/recovery speed can be significantly enhanced (Xun et al, 2018), which was ascribed to formation of heterojunctions
Selected area electron diffraction (SAED) revealed some extra diffraction pots in addition to the main diffraction rings of TiO2 (Figure 4C), corresponding to the (100) and (002) planes of ZnO (JCPDS 36-4521). These results indicated that TiO2 nanotubes modified with ZnO nanoparticles were successfully obtained

Summary

Introduction

Hydrogen is widely used as an important energy carrier and chemical material. Rapid and accurate detection of hydrogen is highly important due to its risky properties such as low minimum ignition energy (0.017 mJ) and high heat of combustion (142 kJ/g H2) (Silva et al, 2012). Hydrogen Gas Sensing ordered nanotubes with nanoparticles of non-noble metal, i.e., SnO2, both the sensitivity and response/recovery speed can be significantly enhanced (Xun et al, 2018), which was ascribed to formation of heterojunctions. There was no evident difference between the TiO2@ZnO sample and the pristine one, indicating that the impregnation treatment did not affect the morphology of the nanotubes.

Results

Conclusion