Effect of indium ion implantation on crystallization kinetics and phase transformation of anodized titania nanotubes usi
- PDF / 549,799 Bytes
- 8 Pages / 584.957 x 782.986 pts Page_size
- 20 Downloads / 221 Views
It Meng Lowa) Department of Physics and Astronomy, Curtin University, Perth, Western Australia 6845, Australia (Received 29 October 2015; accepted 12 February 2016)
Titania nanotube arrays were synthesized electrochemically by anodization of titanium foils, and the synthesized titania nanotubes were then implanted with indium ions. The effect of In-ions implantation on crystallization and phase transformation of titania was investigated using in-situ high-temperature X-ray diffraction and synchrotron radiation diffraction from room temperature to 1000 °C. Diffraction results show that crystalline anatase first appeared at 400 °C in both the non-implanted and the In-implanted materials. The temperature at which crystalline rutile temperature appeared was 600 °C for non-implanted materials and 700 °C for In-implanted materials, and the indium implantation inhibited the anatase-to-rutile transformation. Although In31 is expected to increase oxygen vacancy concentration and then the rate of titania transformation, the observations are consistent with implanted In-ions occupying the Ti sublattice substitutionally and then inhibiting the transformation. The relatively difficult anatase-to-rutile transformation in the In-implanted material appears to result from the relatively large In31 radius (0.080 nm). The In31 partly replaces the Ti41 (0.061 nm), which provides a greater structural rigidity and prevents relaxation in the Ti bonding environment.
I. INTRODUCTION
Titania is known to be a very useful nontoxic, environmentally friendly photocatalyst.1–4 It is a stable, photodurable, inexpensive, and natural aid in the efficient realization of many applications, such as bio-application, dye-sensitized solar cells, photoelectrochemical cells, gas sensors, and hydrogen production.5–9 Titania has three crystal structures: anatase, rutile, and brookite.10–12 In titania phase systems transformation, amorphous titania crystallizes into the most common titania phases, namely anatase, rutile, or a mixture of them, by way of thermal treatment.13,14 The amorphous-to-anatase and subsequent anatase-to-rutile phase transformation behaviors depend on the impurities, morphology, preparation method, dopants, heating rate, calcining temperature, calcining time, and atmospheres.15–19 One-dimensional (1-D) titania nanostructures, for example, nanowires, nanorods, nanobelts, nanofibers, and nanotubes provide unique electronic characteristics, such as a high surface area-to-volume ratio, high electron mobility, or quantum confinement effects, and high
Contributing Editor: Heli Wang a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.83
mechanical strength.1,3,7,8 These characteristics increase the decomposition rate of organic pollutants significantly because photocatalytic reactions occur rapidly and intensely on the catalyst surface.20,21 Various techniques have been used to synthesize 1-D nanostructured titania, including sol–gel,22 microwaves,23 electrochemical anodization,6,24–27 hydrothermal met
Data Loading...
