scholarly journals Visible-Light Active Titanium Dioxide Nanomaterials with Bactericidal Properties

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 124 ◽  
Author(s):  
Chengzhu Liao ◽  
Yuchao Li ◽  
Sie Chin Tjong

This article provides an overview of current research into the development, synthesis, photocatalytic bacterial activity, biocompatibility and cytotoxic properties of various visible-light active titanium dioxide (TiO2) nanoparticles (NPs) and their nanocomposites. To achieve antibacterial inactivation under visible light, TiO2 NPs are doped with metal and non-metal elements, modified with carbonaceous nanomaterials, and coupled with other metal oxide semiconductors. Transition metals introduce a localized d-electron state just below the conduction band of TiO2 NPs, thereby narrowing the bandgap and causing a red shift of the optical absorption edge into the visible region. Silver nanoparticles of doped TiO2 NPs experience surface plasmon resonance under visible light excitation, leading to the injection of hot electrons into the conduction band of TiO2 NPs to generate reactive oxygen species (ROS) for bacterial killing. The modification of TiO2 NPs with carbon nanotubes and graphene sheets also achieve the efficient creation of ROS under visible light irradiation. Furthermore, titanium-based alloy implants in orthopedics with enhanced antibacterial activity and biocompatibility can be achieved by forming a surface layer of Ag-doped titania nanotubes. By incorporating TiO2 NPs and Cu-doped TiO2 NPs into chitosan or the textile matrix, the resulting polymer nanocomposites exhibit excellent antimicrobial properties that can have applications as fruit/food wrapping films, self-cleaning fabrics, medical scaffolds and wound dressings. Considering the possible use of visible-light active TiO2 nanomaterials for various applications, their toxicity impact on the environment and public health is also addressed.

2018 ◽  
Vol 15 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Ravi Kamble ◽  
Smita Mahajan ◽  
Vijaya Puri ◽  
Harish Shinde ◽  
Kalayanrao Garadkar

TiO2 and Cu-doped TiO2 nanoparticles (NPs) with totally extraordinary substance of Cu by exploitation hydrothermal method. The part immaculateness, morphology, molecule estimate, optical properties, and elemental composition of as-incorporated Cu-doped TiO2 NPs were investigated by numerous systematic methods. The XRD designs unveiled Cu-doped TiO2 NPs inside the part unadulterated anatase phase. The plane of (101) XRD and XPS results show the lucky doping of Cu2+ inside the TiO2 lattice. The optical edges of Cu-doped TiO2 demonstrated a transparent light absorption in visible region that assumes an essential part inside the photocatalytic action underneath characteristic daylight. Certain Cu2+ content shows least PL intensity that backings the decrease in recombination rate of charge species. In addition, to get a handle on photocatalytic action, we have tried Cu-doped TiO2 for the degradation of Malachite Green (MG) under visible light. A large portion of 85% degradation was found for Cu-doped TiO2 (1.71 wt.%) underneath daylight minimum of 180 min, severally, that is past that of TiO2 (53%). Also, the degradation of the MG was affirmed by measurement of the chemical oxygen demand of the photodegraded solution. These outcomes demonstrates that the Cu-doped TiO2 NPs are extremely productive for the photodegration of the MG.


2016 ◽  
Vol 13 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Rani P. Barkul ◽  
Farah-Naaz A. Shaikh ◽  
Sagar D. Delekar ◽  
Meghshyam K. Patil

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 235
Author(s):  
Hayette Benkhennouche-Bouchene ◽  
Julien G. Mahy ◽  
Cédric Wolfs ◽  
Bénédicte Vertruyen ◽  
Dirk Poelman ◽  
...  

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.


2013 ◽  
Vol 217 ◽  
pp. 108-118 ◽  
Author(s):  
Segomotso Bagwasi ◽  
Baozhu Tian ◽  
Jinlong Zhang ◽  
Muhammad Nasir

2007 ◽  
Vol 252 (2) ◽  
pp. 296-302 ◽  
Author(s):  
X YANG ◽  
C CAO ◽  
K HOHN ◽  
L ERICKSON ◽  
R MAGHIRANG ◽  
...  

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2261 ◽  
Author(s):  
Abdul Wafi ◽  
Erzsébet Szabó-Bárdos ◽  
Ottó Horváth ◽  
Mihály Pósfai ◽  
Éva Makó ◽  
...  

Catalysts for visible-light-driven oxidative cleaning processes and antibacterial applications (also in the dark) were developed. In order to extend the photoactivity of titanium dioxide into the visible region, nitrogen-doped TiO2 catalysts with hollow and non-hollow structures were synthesized by co-precipitation (NT-A) and sol–gel (NT-U) methods, respectively. To increase their photocatalytic and antibacterial efficiencies, various amounts of silver were successfully loaded on the surfaces of these catalysts by using a facile photo-deposition technique. Their physical and chemical properties were evaluated by using scanning electron microscopy (SEM), transmission electron microscopy–energy dispersive X-ray spectroscopy (TEM–EDS), Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), and diffuse reflectance spectra (DRS). The photocatalytic performances of the synthesized catalysts were examined in coumarin and 1,4-hydroquinone solutions. The results showed that the hollow structure of NT-A played an important role in obtaining high specific surface area and appreciable photoactivity. In addition, Ag-loading on the surface of non-hollow structured NT-U could double the photocatalytic performance with an optimum Ag concentration of 10−6 mol g−1, while a slight but monotonous decrease was caused in this respect for the hollow surface of NTA upon increasing Ag concentration. Comparing the catalysts with different structures regarding the photocatalytic performance, silverized non-hollow NT-U proved competitive with the hollow NT-A catalyst without Ag-loading for efficient visible-light-driven photocatalytic oxidative degradations. The former one, due to the silver nanoparticles on the catalyst surface, displayed an appreciable antibacterial activity, which was comparable to that of a reference material practically applied for disinfection in polymer coatings.


2011 ◽  
Vol 80 (11) ◽  
pp. 114706 ◽  
Author(s):  
Shi Wei Chen ◽  
Jenn Min Lee ◽  
Sunny Chiang ◽  
Shu Chih Haw ◽  
Yu Chia Liang ◽  
...  

2015 ◽  
Vol 1101 ◽  
pp. 299-302 ◽  
Author(s):  
Hanggara Sudrajat ◽  
Sandhya Babel

A visible light active nitrogen-doped ZnO (N-ZnO) was synthesized using a solvent-free mechanochemical method and applied to degrade methylene blue (MB) dye in aqueous suspension. Results showed that nitrogen doping improved the photocatalytic activity of pristine ZnO by extending its spectral response to visible region. Using 2 g/L of N-ZnO, 98% MB with the initial concentration of 10 mg/L could be degraded within 2 h at pH 7 under 11.3 klux of visible light irradiation. After 6th run, it still exhibited appreciable photocatalytic activity with 94% MB degradation, indicating its high reusability though a simple pretreatment was performed.


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