Abstract
Doping of titania nanotubes is one of the efficient way to obtain improved physical and chemical properties. Through electrochemical anodization and annealing treatment, Ni-doped TiO2 nanotube arrays were fabricated and their hydrogen sensing performance was investigated. The nanotube sensor demonstrated a good sensitivity for wide-range detection of both dilute and high-concentration hydrogen atmospheres ranging from 50 ppm to 2% H2. A temperature-dependent sensing from 25°C to 200°C was also found. Based on the experimental measurements and first-principles calculations, the electronic structure and hydrogen sensing properties of the Ni-doped TiO2 with an anatase structure were also investigated. It reveals that Ni substitution of the Ti sites could induce significant inversion of the conductivity type and effective reduction of the bandgap of anatase oxide. The calculations also reveal that the resistance change for Ni-doped anatase TiO2 with/without hydrogen absorption was closely related to the bandgap especially the Ni-induced impurity level.
Highlights
There is a strong need to develop robust hydrogen sensors for use in hydrogen cars, chemical production, and spacecraft fuel cells as well as other long-term applications [1,2]
To explore the effect of Ni doping on the bandgap and interaction of hydrogen with TiO2 oxide, the first-principles calculations were performed with the CASTEP code [29] based on density functional theory
We found that the hydrogen sensing properties of the Ni-doped TiO2 nanotubes were enhanced with increase of the working temperature
Summary
There is a strong need to develop robust hydrogen sensors for use in hydrogen cars, chemical production, and spacecraft fuel cells as well as other long-term applications [1,2]. A key requirement for these sensors is the ability to selectively detect hydrogen at lower temperatures with minimal power use and weight. Oxide nanotube has become a potential candidate for the development of the targeted robust hydrogen sensors [3,4,5]. TiO2-based gas sensors have been widely used mainly because of their inert surface properties and the change of electrical resistance after adsorption of hydrogen [6]. As a wide bandgap semiconductor material [7,8], anatase TiO2 (Eg ≈ 3.2 eV) usually suffers from a poor electrical conductivity and resistance increase of electronic devices; anatase TiO2 oxide seems to be probably hard to become an ideal material used for hydrogen detecting.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
