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Nano Titanium Dioxide -An Effective Photocatalyst for Emerging Applications

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Nano Titanium Dioxide -An Effective Photocatalyst for Emerging Applications International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-8 Issue-10, August 2019 Nano Titanium Dioxide -An Effective Photocatalyst for Emerging Applications Ragavi Priyadharshani Raja, Geetha Kathiresan, R. Ilavarasi materials are in a nanoscale, could be properly characterized Abstract: Titanium dioxide (TiO2) is a widely studied material with some major techniques which are transmission electron and exists in three major crystal structures: rutile, brookite and microscopy (TEM) or scanning electron microscopy (SEM). anatase. Due to its advantages in high chemical and thermal The crystallographic structure of TiO2, can be identified with stability, non-toxicity, high catalytic activity, resistance to the help of X-ray diffraction(XRD) techniques and the X-ray corrosion, and high reactivity under ultraviolet light (<387 nm),it can be used in many applications such as photo catalysis, Photoelectron Spectroscope (XPS) techniques gives the photovoltaics, sensors, hydrogen generators batteries, information about chemical compositions and oxidation self-cleaning, electrochromic devices and also used in some states of the surface species of the respective materials in the biomedical application for site specific drug delivery . These research fields [6]. To reveal the elemental composition on applications in various fields depends not only on the properties of some nanocomposites based researches, Energy-dispersive the TiO material but also it involves in modifying TiO structure 2 2 X-ray spectroscopy EDS was carried out. The major and doping of other element on it which will show adverse impact properties of titanium dioxide such as thermal, structural, in application of TiO2 with the surrounding environment. In this review, we are discussing about the synthesis, properties, and electronic and optical are discussed in this review. Of which applications of titanium dioxide nanoparticle (TiO2 NP) in various above mentioned properties, titanium dioxide has wide fields. application with its optical properties. As it is transparent in Keywords: TiO2 Synthesis, Properties, Photocatalyst, Photo visible light region, it should be doped or sensitized with Electrochemical detection. some other materials for enhancing optical property and activities of TiO nanomaterials, thereby increasing its I. INTRODUCTION 2 application as a photocatalyst and sensing, photovoltaics, Titanium dioxide (TiO2) is a well-known semiconductor water splitting, photo-/electrochromic, and hydrogen storage nanomaterial has been proved to be an excellent basic and hydrogen generated batteries. As a promising photo material in many other applications. Nowadays, its catalyst, TiO2 nanoparticles playing an important role in toxic application has been considerably increased in the field of molecule detection based researches in the environmental nanoscience and nanotechnology, because of its enhanced pollution challenges. Also the preparation and the properties chemical and physical properties in the nanoscale level. of titanium dioxide nanomaterials based researches are Based on its synthesis and properties, many other reviews discussed in this review. The flow chart for the types of and reports have been done. Those researches has been done nanomaterials as shown in the Figure.1. with the promising chemical and physical properties which includes photoelectric activity, large surface area, high stability[1], adsorption edge energy, efficient separation of the charge carriers, crystallite size[2], high sensitivity, selectivity in the field of photo electrochemistry detection[3], high reactivity under ultraviolet light (<387 nm)[4], biological inert nature and high electronic mobility [5]. Here, in this review we are mainly concentrating in synthesis, properties, modification and applications of titanium dioxide (TiO ) nanomaterials. At nanometre scale, 2 Fig. 1: The flow chart for the types of nanomaterials. the synthesis of titanium dioxide (TiO2) could be in the form of nanoparticles, Nano rods, nanowires, nanocomposites and II. SYNTHESIS METHODS nanotubes which are well categorized with the appropriate preparation method and also the synthesis of The synthesis of nanomaterials, nanotubes, nanorods, nano composites by sol-gel method is explained here. In this mesoporous/nanoporous TiO2, and photonic materials are well defined. Those preparatory methods are discussed in this process, a sol (colloidal substance) is obtained from the review with proper procedures and prepared respective hydrolysis and polymerization reaction of the precursors. At the end of polymerization state, conversion of liquid phase to solid gel phase occur. There are numerous method available Revised Manuscript Received on August 05, 2019. for synthesizing nanomaterials like emulsion techniques, Ragavi Priyadharshani Raja, M.Tech, Dept. of Nanotechnology, spray pyrolysis, precipitations, wet chemical synthesis[7,8], Periyar Maniammai Institute of Science & Technology, Thanjavur, Tamilnadu. and production of thin films based on nanomaterials were Geetha Kathiresan*, Assistant Professor, Dept. of Nanotechnology, produced by spin coating or Periyar Maniammai Institute of Science & Technology, 613403, Tamilnadu. dip coating. Some of those R. Ilavarasi, Assistant Professor, Dept. of Nanotechnology, Periyar Maniammai Institute of Science & Technology, 613403, Tamilnadu. Published By: Retrieval Number J10530881019/2019©BEIESP Blue Eyes Intelligence Engineering DOI: 10.35940/ijitee.J1053.0881019 4464 & Sciences Publication Review on Titanium Dioxide Synthesis and Its Application on Prospecting Photocatalysis synthesis method are explained here as follows. B. Nano Tubes A. Nano Powders For the preparation of TiO2 nanotubes and nanorods, the preparatory methods were almost same. Titanium For the synthesis TiO nanomaterial, Titanium tetra iso 2 isopropoxide (TI) was used as a precursor which was propoxide [Ti(OCH(CH ) )] , SigmaAldrich, 97%], 3 2 4 dissolved in ethanol to synthesize TI solution. This TI iso-propanol [(CH3)2CHOH, Sigma-Aldrich, 99.7%] and solution should be added with the mixture of ethanol, nitric acid [HNO ] were used. Here, they have added 3 acetylacetone and water to yield TiO sol with different molar Titanium tetra iso propoxide into the solution containing 2 concentrations at room temperature. After that anodic iso-propanol and deionized water under constant stirring at alumina template membrane having pores with the uniform 80º C into the round bottom beaker. After 1 h, concentrated diagram ranging from 200-250 nm, is dipped frequently in to HNO3 mixed with deionized water was added into the TTIP this tio2 sol. After drying this template for 1 day and allowed solution and keep it under constant stirring at 60 ºC for 6 h to heated in air at 400 oC, it could give nanorods and highly viscous sol gel was obtained. These prepared sol gel, nanotubes in the pores of AA template membrane [11]. undergone annealing process to form a powdered form of TiO2 nanocrystalline. Further preparation of TiO2 film, the C. Nano Wires prepared powder was added to the solution of iso-propanol in TiO2 nanowires have been prepared by electrophoretic the ratio of 1:10. The TiO2 nanoparticles deposited on deposition of TiO2 sol in to the pores of an AA membrane titanium substrate using the dip coating method. Further template maintaining at 500 °C for 24 h. To isolate TiO2 nano optical studies, The TiO2 film were prepared on the two glass wires , AAM template is dissolved in a 5 wt %NaOH solution substrates. Its crystalline nature is observed by XRD [12]. TiO2 nanorod array could be synthesized by dropwise techniques and it was found to be rutile and anatase [9]. The adding the mixture of ethanol and deionized water in to the FE SEM image of the TiO2 nano powder as shown in the Fig. solution of tetrabutylorthotitanate under magnetic stirring. 2, which reveals that they are spherical in shape and clustered Finally it was deposited on the ZnO Nano rod and allow it to on the glass substrate and Fig. 3 represents the XRD image of dry (100 ◦C for 10 min) and heated in air (550◦C for 1 h) to TiO2 nanoparticles. By dissolving the titanium tetrachloride obtain TiO2 nanorod array [13]. in the mixture of solutions containing ethanol and acetic acid. Final mixture was kept under autoclave at 180oC, after this D. Other Form Of TiO2 process it was cool down to room temperature. A fine powder Potassium titanium oxide oxalate dehydrate (PTO) was of TiO2 was obtained after drying the rinsed product for 2h used as an precursor element in the synthesis of anatase [10]. hierarchically cactus like TiO2 array. This element was added to a ultrapure water followed by adding diethylene glycol. This mixture was kept in an autoclave where the cleaned FTO substrate was introduced and the entire setup was maintained at a temperature of 160o C for 3-12h. At the end of the reaction, FTO substrate was taken out, rinsed well with ultrapure water and dried with ambient air at 80 ◦ C, annealing at 450 ◦ C for 2 hr [14] .Hydrothermal synthesis of nano particles were developed nowadays because it could yield nanocrystals directly as compared to other processes such as sol gel and co precipitation methods because it would need calcination and milling, it could leads agglomeration and degradation of the particle surface. For the synthesis of TiO nanoparticles, titanium isopropoxide (Ti(OC H ) , was 2 3 7 4 hydrolyzed with deionized water under vigorous stirring at Fig. 2: FE SEM image of TiO2
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