Alternating current electrophoretic deposition (EPD) of TiO2 nanoparticles in aqueous suspensions

Electrophoretic deposition of photocatalytic materials

Powdered photocatalytic materials have been successfully applied for the degradation of organic and inorganic pollutants as well as for hydrogen production and CO₂ photo-reduction. However, the development of strategies for the preparation of photoactive coatings is a hot topic since it is a promising step for its use in photocatalytic reactors on an industrial scale. Electrophoretic deposition is a versatile technique capable to produce coatings of nanoparticles at a relative low cost and with an excellent quality and control of the deposited material. This work summarizes the fundamental aspects of the electrophoretic deposition process, as well as the latest contributions in the deposition of several photocatalytic materials including TiO₂ and other UV-photocatalysts like ZnO, ZnS, SrTiO₃ and PbMoO₄ in addition to visible-light-driven photocatalysts such as Bi₂O₃, CdS, CdSe, g-C₃N₄, among others. Furthermore, the morphological features of the coatings along with the repercussion in the photocatalytic performance are issues discussed in the present review, based on the effect of the multiple parameters of the electrophoretic process such as the applied voltage, the deposition time, the inter-electrode distance, the concentration of the particles, the solvents and additives.

Facile preparation of porous In2TiO5-rutile composite nanotubes by electrospinning and sensitivity enhancement in NO2 gas at room temperature

Porous In2TiO5-rutile composite nanotubes (IRCNs) were synthesized via a facile one-step synthesis of the electrospinning approach by using tetrabutyl titanate (TBT), indium nitrate, and polyvinylpyrrolidone (PVP) as a soft-template followed by two-step calcination. The porous composite nanotubes with a bigger surface area have single-crystalline rutile with (110) crystal plane, and the sensor fabricated by it with a content of 12.5 at% In2TiO5 (IRCN2) has shown a response of 4.04 to 100 ppm NO2 at room temperature (RT), which was 20 times as high as the pure In2TiO5 sensor under the same conditions. The IRCN2 sensor had excellent selectivity compared with other gas species such as CO, H2, NH3, H2S and CH4 at RT. The enhanced sensing properties were attributed to the synergy of integrated In2TiO5 and rutile, heterojunction of single-crystal, and its nanotubular structure. Hence, the IRCN2 sensor has a potential application for the development of novel gas sensors at RT.

Electrophoretic Deposition of Chitosan/h-BN and Chitosan/h-BN/TiO₂ Composite Coatings on Stainless Steel (316L) Substrates

This article presents the results of an experimental investigation designed to deposit chitosan/hexagonal boron nitride (h-BN) and chitosan/h-BN/titania (TiO₂) composites on SS316L substrates using electrophoretic deposition (EPD) for potential antibacterial applications. The influence of EPD parameters (voltage and deposition time) and relative concentrations of chitosan, h-BN and TiO₂ in suspension on deposition yield was studied. The composition and structure of deposited coatings were investigated by FTIR, XRD and SEM. It was observed that h-BN and TiO₂ particles were dispersed in the chitosan matrix through simultaneous deposition. The adhesion between the electrophoretic coatings and the stainless steel substrates was tested by using tape test technique, and the results showed that the adhesion strength corresponded to 3B and 4B classes. Corrosion resistance was evaluated by electrochemical polarization curves, indicating enhanced corrosion resistance of the chitosan/h-BN/TiO₂ and chitosan/h-BN coatings compared to the bare stainless steel substrate. In order to investigate the in-vitro inorganic bioactivity, coatings were immersed in simulated body fluid (SBF) for 28 days. FTIR and XRD results showed no formation of hydroxyapatite on the surface of chitosan/h-BN/TiO₂ and chitosan/h-BN coatings, which are therefore non bioactive but potentially useful as antibacterial coatings.

Anode-selective coating of titanium(iv) oxide (TiO2) using electrophoretic sulfone-containing click polyester

We synthesized aliphatic and aromatic poly(ester-sulfide)s, via a thiol–ene click polymerization of ester-containing dialkenes with dithiols. Subsequent Oxone oxidation led to the corresponding poly(ester-sulfone). We then prepared a composite with TiO₂ using electrophoretic deposition. The composite was selectively deposited onto a stainless-steel anode.