Fabrication of a self‐doped TiO₂ nanotube array electrode for electrochemical degradation of methyl orange

Abstract

Self‐doped TiO2 nanotube array (DTNA) electrodes were fabricated through anodic oxidation combined with cathodic reduction. The morphology and structural features of pristine TiO2 nanotube arrays and DTNA electrodes were studied through scanning electron microscopy, X‐ray diffractometry, and X‐ray photoelectron spectroscopy. An accelerated life test was used to test the electrode service lifetime and thus the electrode's stability. The service lifetime of the DTNA electrode prepared at constant 40 V for 6 hr was approximately 338.7 hr at constant 1 mA/cm2 in a 1 M NaClO4 solution. Methyl orange (MO) was employed as the degradation probe for measuring electrochemical oxidation performance. The color removal rate of 200 mg/L MO of the DTNA electrode (85.2% at 1 mA/cm2) was greater than that of the Ti/IrO2 electrode (31.1% at 1 mA/cm2). The larger the surface area of the DTNA electrode is, the more conductive the electrode is for the degradation of organic substances. Organic degradation on the DTNA electrode occurred primarily through an indirect pathway (producing [∙OH]).

TiO2 Self-Assembled, Thin-Walled Nanotube Arrays for Photonic Applications

“…Due to the additional electron doping that occurs during the growth process [4,13], we consider RI data modified by the presence of free electrons in a Drude model. This reduces the permittivity and thus the sine in Equation (7) is shifted.…”

“…Experimentally [4,13] it was observed that additional charge carriers are injected into the system during the growth process of TiO2 nanotubes. We can account for this effect considering RI data modified by the presence of free electrons in a Drude model (in Gauss units) ϵfalse(ωfalse)=ϵTiO2−4πneω(ω+iγ).We assume a small, intrinsic damping γ=0.014pteV, a varying carrier density of ne.…”

“…Such arrays have wide applications in sensing [5], as filters and nanosized test tubes in biomedicine [6], as photonic crystal fiber lasers and demultiplexers [7,8,9], and as nanostructured electrodes for (surface enhanced Raman) spectroscopy [3,4]. In addition, the possible enhancement of reaction or transport rates due to a large surface area, see Figure 1a, strong electron confinement and short diffusion paths make them highly interesting nanostructures for (photo-)catalysis [10,11,12,13] and photovoltaics (PV) [14,15,16,17,18]. While typically grown on Ti substrates or alloys, TiO2 NTs can be produced as membranes through a lift-off process [2].…”

“…This article investigates systematically the optical modes of such structures for a wide parameter range. We take a detailed look at the optical properties of photonic crystals made from regular TiO2 NT arrays with an emphasis on the influence of the NT wall thickness and charge carrier doping during the anodization [4,13], two parameters not typically available in nanostructures fabricated with, e.g., lithographic techniques. The reflection and near-field spectra are obtained from Rigorous Coupled Wave Analysis (RCWA) [24,25,26] simulations.…”

Magnetron Sputtering Thin Films as Tool to Detect Triclosan in Infant Formula Powder: Electronic Tongue Approach

“…On this base, Multi-Walled Carbon Nanotubes (MWCNTs) and titanium dioxide (TiO 2 ) thin films were studied. TiO 2 thin films have been used in electrocatalytic, photocatalytic and photo electrocatalytic degradation of organic pollutants including TCS [26][27][28][29]. TiO 2 presents adsorption ability to the lipopolysaccharide, due to the high relative surface area, hydrophilic property and electrostatic attraction [30].…”