Nanoporous Titanium Oxide Morphologies Produced by Anodizing of Titanium

Abstract

A quick and dependable technique has been developed that allows us to selectively produce anodized TiO2 in the form of nanotubes. The process employs mild chemical conditions and ambient temperature. The method can consistently produce nearly 100% surface coverage of nanotubes within 10 min of anodizing. Anodizing in relatively high pH electrolytes for 1 hour permitted us to produce nanotubes of 2μm length. We attribute the repeatability of our results to a brief pre-anodizing etching step that consistently leads to excellent anodizing results. Without this etching step, we experienced very poor consistency in that only small patches of titania nanotubes were formed.

Titanium Dioxide Nanotube Arrays Fabricated by Anodizing Processes

“…Especially noteworthy is the length of nanotubes formed in near-neutral pH solutions of fluoride. 17 In recent work, Sklar et al 18 reported a variety of solution compositions that were used for anodic formation of TONT. In a recent paper from our laboratory, ZrO 2 nanotube arrays were prepared via an electrochemical route similar to that used in the present paper ͑Lee et al 19 ͒.…”

Synthesis of Pt/TiO[sub 2] Nanotube Catalysts for Cathodic Oxygen Reduction

“…This same group also studied oxide nanotube formation on several different metals that included zirconium, hafnium, and tungsten. Sklar et al 22 reported nanotube formation by EAP in several electrolyte compositions, and discovered that TONT arrays of about 2 µm length could be prepared in as little as 1 h ͑rather than 6 or 20 h͒ if a short "pre-etch" of 30 s was carried out in 0.5 wt % HF before anodizing.The morphology of TONT formation via EAP consists of an ordered array of TONT of rather uniform dimensions for a fixed condition of formation. The diameter, wall thickness, separation, and number density of tubes are affected by voltage, time, and electrolyte composition, as reported by the references above.…”

“…This same group also studied oxide nanotube formation on several different metals that included zirconium, hafnium, and tungsten. Sklar et al 22 reported nanotube formation by EAP in several electrolyte compositions, and discovered that TONT arrays of about 2 µm length could be prepared in as little as 1 h ͑rather than 6 or 20 h͒ if a short "pre-etch" of 30 s was carried out in 0.5 wt % HF before anodizing.…”