High Electromagnetic Field Enhancement of TiO₂ Nanotube Electrodes

Abstract

We present the fabrication of TiO nanotube electrodes with high biocompatibility and extraordinary spectroscopic properties. Intense surface-enhanced resonance Raman signals of the heme unit of the redox enzyme Cytochrome b were observed upon covalent immobilization of the protein matrix on the TiO surface, revealing overall preserved structural integrity and redox behavior. The enhancement factor could be rationally controlled by varying the electrode annealing temperature, reaching a record maximum value of over 70 at 475 °C. For the first time, such high values are reported for non-directly surface-interacting probes, for which the involvement of charge-transfer processes in signal amplification can be excluded. The origin of the surface enhancement is exclusively attributed to enhanced localized electric fields resulting from the specific optical properties of the nanotubular geometry of the electrode.

Molecular Engineering of Conjugated Acetylenic Polymers for Efficient Cocatalyst‐free Photoelectrochemical Water Reduction

“…Upon introducing SCN − (10 m m ) into the electrolyte, the photocurrent of pDET/Cu remained almost the same, demonstrating that the Cu species in pDET/Cu was not the active center for PEC HER (Supporting Information, Figure S43). Then, operando electrochemical‐Raman spectroscopy was carried out to trace the alterations of their bond information during the PEC HER. According to their absorption and IPCE spectra, two laser lines (594 nm and 647 nm, one close and one far below the optical band gap) were used to record the Raman spectra of thiophene‐based pDET as a function of applied potential (Figure and Supporting Information, Figures S45 and S46).…”

Nanoporous thin films in optical waveguide spectroscopy for chemical analytics

“…Self-organized, anodic TiO 2 nanotube (NT) arrays offer a large spectrum of possible applications [22]. Among the most important optical implementations is their use as photonic crystals in fiber lasers and demultiplexers, and as nanostructured electrodes for surface enhanced Raman spectroscopy [30,31]. Independent of the chemical surroundings, optical field enhancement can occur as a result of the presence of additional free electrons in TiO 2 [31].…”

“…Among the most important optical implementations is their use as photonic crystals in fiber lasers and demultiplexers, and as nanostructured electrodes for surface enhanced Raman spectroscopy [30,31]. Independent of the chemical surroundings, optical field enhancement can occur as a result of the presence of additional free electrons in TiO 2 [31]. Charge transfer processes and photon scattering are enhanced through the directionality of incoming light which is triggered through the nanotube morphology [32].…”

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

“…To lower the cost of electrode production, this study investigated the use of Ti metal bases to prepare an active anode for application to wastewater treatment. One‐dimensional titanium dioxide nanotubes have become a popular research topic in the field of chemistry and materials due to their large specific surface area, high mechanical strength, and favorable biocompatibility . Self‐doped TiO 2 nanotube array (DTNA) electrodes prepared though anodic oxidation combined with cathodic reduction have the advantages of high arrangement regularity and a large specific surface area.…”