Preparation and properties of Co3O4-doped TiO2 nanotube array electrodes

Facile preparation of MnO2-TiO2 nanotube arrays composite electrode for electrochemical detection of hydrogen peroxide

The MnO₂-TNTA composite electrodes were obtained through depositing MnO₂ into TiO₂ nanotube arrays (TNTA) by successive ionic layer adsorption reaction (SILAR) and subsequent hydrothermal method. The MnO₂-TNTA nanocomposites were used as electrochemical sensors for the detection of hydrogen peroxide (H₂O₂). The preparation conditions of MnO₂-TNTA electrodes and test conditions affect the electrochemical detection performance significantly. The optimal conditions are listed as follows: the number of SILAR cycles, 6 times; KMnO₄ solution temperature, 50 °C; supporting electrolyte, 0.5 M NaOH. Under these conditions, the MnO₂-TNTA electrode exhibits the best performance for detecting H₂O₂. The optimized MnO₂-TNTA electrode has a minimum detection limit of 0.6 μM (S/N = 3) and a linear range of 5 μM ∼ 13 mM, which is much superior to the previously-reported electrodes. Moreover, the optimized MnO₂-TNTA electrode possesses high selectivity, excellent stability and good reproducibility in the detection of H₂O₂. When used in the determination of H₂O₂ content in actual samples including disinfectant and milk, it also shows good accuracy, ideal recovery (96.00% ∼ 102.67%) and high precision (RSD < 4.0%).

Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?

Nanomedicine has seen a significant rise in the development of new research tools and clinically functional devices. In this regard, significant advances and new commercial applications are expected in the pharmaceutical and orthopedic industries. For advanced orthopedic implant technologies, appropriate nanoscale surface modifications are highly effective strategies and are widely studied in the literature for improving implant performance. It is well-established that implants with nanotubular surfaces show a drastic improvement in new bone creation and gene expression compared to implants without nanotopography. Nevertheless, the scientific and clinical understanding of mixed oxide nanotubes (MONs) and their potential applications, especially in biomedical applications are still in the early stages of development. This review aims to establish a credible platform for the current and future roles of MONs in nanomedicine, particularly in advanced orthopedic implants. We first introduce the concept of MONs and then discuss the preparation strategies. This is followed by a review of the recent advancement of MONs in biomedical applications, including mineralization abilities, biocompatibility, antibacterial activity, cell culture, and animal testing, as well as clinical possibilities. To conclude, we propose that the combination of nanotubular surface modification with incorporating sensor allows clinicians to precisely record patient data as a critical contributor to evidence-based medicine.

The Electrochemical Oxidation of Hydroquinone and Catechol through a Novel Poly-geminal Dicationic Ionic Liquid (PGDIL)-TiO2 Composite Film Electrode

A novel poly-geminal dicationic ionic liquid (PGDIL)-TiO₂/Au composite film electrode was successfully prepared by electrochemical polymerization of 1,4-bis(3-(m-aminobenzyl)imidazol-1-yl)butane bis(hexafluorinephosphate) containing polymerizable anilino groups in the electrolyte containing nano-TiO₂. The basic properties of PGDIL-TiO₂/Au composite films were studied by SEM, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The SEM results revealed that the PGDIL-TiO₂ powder has a more uniform and smaller particle size than the PGDIL. The cyclic voltammetry results showed that the catalytic effect on electrochemical oxidation of hydroquinone and catechol of the PGDIL-TiO₂ electrode is the best, yet the R_ct of PGDIL-TiO₂ electrode is higher than that of PGDIL and TiO₂ electrode, which is caused by the synergistic effect between TiO₂ and PGDIL. The PGDIL-TiO₂/Au composite electrode presents a good enhancement effect on the reversible electrochemical oxidation of hydroquinone and catechol, and differential pulse voltammetry tests of the hydroquinone and catechol in a certain concentration range revealed that the PGDIL-TiO₂/Au electrode enables a high sensitivity to the differentiation and detection of hydroquinone and catechol. Furthermore, the electrochemical catalytic mechanism of the PGDIL-TiO₂/Au electrode was studied. It was found that the recombination of TiO₂ improved the reversibility and activity of the PGDIL-TiO₂/Au electrode for the electrocatalytic reaction of HQ and CC. The PGDIL-TiO₂/Au electrode is also expected to be used for catalytic oxidation and detection of other organic pollutants containing -OH groups.