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Sol-gel template synthesis of mesoporous carbon-doped TiO2 with photocatalytic activity under visible light
... Within C doping, it is also noteworthy the Ovodok and group study where the surfactant Pluronic F-127 is used as structure director and source of C dopant. The resulting material was put to degrade Rhodamine B using visible light [59]. ...
Titanium dioxide (TiO2) is one of the most widely used metal dioxides for applications such as semiconductors, photocatalysts, pigments, pharmaceutical excipients, and antimicrobials. Applications of TiO2 are increasing over time, and new properties are being added as it becomes available in nanometric size. This review presents the challenges and the advances in the use of surface-modified TiO2 in various fields: as a photocatalyst and catalyst focusing on environmental remediation of wastewater, its role in solar cells, in biomedical and antimicrobial applications, its role in various composites, especially textile fibers, and finally as a polymer filler in multiple matrices. All the advances discussed here are primarily concerned with how titanium dioxide crystals can be surface modified at the new properties that can be achieved, considering the advantages and drawbacks of every modification discussed here.
Graphical abstract
Surface modification of TiO2 and its use as A) complexes for biomedical applications, B) photocatalyst, C) substrate in solar cells, and D) drug delivery systems
... The UV-vis absorption spectra of the samples are compared in Figure 7. The absorption of pure TiO 2 is mostly exhibited in the UV region (Bakre and Tilve 2018;Buraso et al. 2018;Ovodok et al. 2018), and this occurred in this work for the unmodified TiO 2 sample (Bare-TiO 2 ). However, for the modified TiO 2 samples, a significant shift of the optical absorption edges toward the visible-light region was observed which was associated with the doped elements. ...
A new visible photoactive catalyst (Cu, S/PEG-PVA/TiO2) was synthesized by the sol-gel method. In addition, Cu, S/TiO2 and Bare TiO2 were synthesized to compare their properties and activities. The synthesized catalysts were characterized using XRD, N2 adsorption–desorption measurements, SEM, TEM, EDX, UV-Vis spectroscopy and TGA. The photocatalytic activities of the synthesized photocatalysts were evaluated by measuring the photocatalytic degradation of 4-nitrophenol under visible light irradiation. Then, the impacts of three parameters, (catalyst loading, pH and H2O2 concentration) for optimization and modelization of the 4-nitrophenol photodegradation were studied using the response surface methodology. Optimal conditions obtained from statistical analysis at a catalyst loading of 1 gL⁻¹, pH of 3.98 and H2O2 concentration of 8 mg/L have shown the highest 4-NP percentage degradation of 70.5% in 1 h. The results predicted by the models were found to be in good agreement with those obtained by performing the experiment (R² = 0.9443 and Adj-R2 = 0.9038).
... Sol-gel has a simple operation and equipment, and no special conditions are required because the reaction occurs at room temperature and atmospheric pressure. Sol-gel was easy, inexpensive, and produced high-purity products (Ovodok, et al., 2018). ...
The carbon-doped TiO2 have been synthesized through sol-gel method using Solanum tuberosum starch as carbon source. The carbon precursor composition and reaction time were varied to study its influence to the crystal structure and electronic structure of resulted material. The C- TiO2 product was characterized by XRD, UV-Vis DRS, FTIR, and photocatalytic activity examine by methylene blue degradation. The results showed that variations in the composition of the carbon precursor and reaction time affected the characteristics of the crystal structure and photocatalyst activity of C- TiO2. The optimum variation was found in the variation of 1.5 gram carbon composition and 24 hours hydrolysis time which had the smallest particle size and lowest bandgap energy. The highest photocatalyst activity was obtained at a 24-hour reaction time variation with 59.375% percent of methylene blue degraded in the second-order reaction with a k value of 2.1351.
... The first two objectives have been extensively investigated in recent years. For example, doping with transition elements (Ag, Fe, V, Bi, Sn and Mo) [26][27][28][29][30][31][32][33][34] and non-metallic elements (C, N, S, P and B) [35][36][37][38] has been shown to be ways of modifying the electronic structure and decreasing TiO 2 E bg . Doping and/or modification with boron (B) has been shown to improve the photoactivity of TiO 2 , as it can occupy and displace the positions of the interstitial oxygen network, creating intermediate energy levels in TiO 2 E bg [39,40]. ...
The photoelectrocatalysis (PEC) using B-doped TiO2 photo-anodes for degradation of the propyphenazone (PPZ) was investigated. For this, four different composites based on TiO2 and TiO2-x%B (x = 1, 3 or 5) were synthesized by sol-gel method and supported on titanium substrate by the dip-coating technique. The morphology, optical and electrochemical properties of photo-anodes were evaluated by SEM, TEM, XPS, TGA, DSC, XRD, FTIR, DRS, and sweep voltammetry, respectively. The influence of pH (3, 6 or 9) and electrical potential intensity (+1 V, +2 V or +3 V) used in PEC were evaluated by kinetic study. To understand the synergistic effect of the composition of the photoelectrochemical system, photolysis (PS), electrocatalysis (EC) and photocatalysis (PC) experiments were realized under comparative conditions. Doping 3% of B into TiO2 promoted a decrease in band gap energy (Ebg = 2.91 eV), thus providing better radiation absorption and greater generation of charge carriers on the surface of the photo-anode. Characterization analyzes indicate the presence of B2O3 coexisting with TiO2. The most promising results were obtained using Ti/TiO2-3%B photo-anode (vs a DSA cathode), applying +1 V at pH 6, resulting in 91% of PPZ degradation after 60 min of PEC treatment. Toxicity tests using A. salina and L. sativa showed that the effluent generated after 2 h of PEC treatment of 30 mg L⁻¹ of PPZ is non-toxic for the studied species. Up to 13 by-products formed during the PEC and PS treatment were detected and a proposal pathway involving possible routes of PPZ degradation were presented.
... Non-metallic doping of TiO 2 is more effective than metal doping due to the reduction of recombination centers [19]. Various nonmetals (N [50][51][52][53][54][55][56], B [57][58][59][60], C [61][62][63][64][65], P [66][67][68][69], S [70][71][72], F [73][74][75][76][77][78], Br [79,80]) are used to improve the photocatalytic activity of TiO 2 in the field of visible light [10,19,81]. ...
Water and air pollutants pose a significant environmental problem worldwide and photocatalysis is one way to address this global issue. Photocatalytic degradation of toxic substances under the influence of visible electromagnetic radiation is widely used for wastewater treatment. The most promising method of pollutant removal is the use of photocatalysts based on titanium (IV) oxide, which are recognized as one of the most effective due to chemical resistance, non-toxicity and low cost. However, their practical application is limited by the rapid recombination of photogenerated charge carriers and selective absorption of light in the UV region due to the large width of band gap. To solve this scientific and practical problem, it is necessary to modify the TiO2 surface, for example, through metallic or nonmetallic doping, in order to increase its photocatalytic activity due to additional absorption in the visible range of the spectrum. This review presents an analysis of current research on ways to increase the efficiency of TiO2-based photocatalysts.
... Namun, titania sebagai fotokatalis menunjukkan beberapa kelemahan intrinsik, seperti penyerapan cahaya tampak terbatas karena celah pita lebar, yang menghambat efisiensi dan aplikasi yang lebih luas . [6] Pada review ini digunakan doping senyawa non logam (F,N,C) untuk meningkatkan aktivitas fotokatalis pada serapan cahaya tampak yang hasilnya dianalisis menggunakan XRD dan DRUV-Vis ...
ABSTRAK Titania (TiO2) merupakan material yang banyak digunakan sebagai fotokatalis yang didasarkan pada sifat semikonduktornya. TiO2 memiliki beberapa keunggulan dibandingkan dengan oksida logam yang lain yaitu fotoreaktif, inert secara kimia dan biologi, anti korosi, non toxic, dan kemampuannya untuk digunakan secara berulang tanpa kehilangan aktifitas katalitik.TiO2 dapat disintesis dengan beberapa metode salah satunya dengan menggunakan metode sol-gel. Fase kristal TiO2 dianalisa dengan XRD menunjukkan fase kritsal anatase. Namun aktivitas fotokatalis TiO2 pada cahaya uv sehingga dapat mempengaruhi performa jika diaplikasikan pada cahaya tampak. Sehingga diperlukan modifikasi pergeseran merah pada serapan cahaya merah dengan pengaruh dopan. Pada review ini mengunakan dopan non logam seperti karbon, nitrogen dan fluor untuk meningkatkan aktivitas serapan cahaya tampak yang dianalisa dengan spektrum UV-Vis. Hasil tersebut dapat menjadi investigasi lebih lanjut dalam pengaplikasian TiO2 dengan pengaruh dopan (C, N, dan F) terhadap aplikasi fotokatalis dalam cahaya tampak. Kata Kunci: TiO2, Dopan, Cahaya Tampak, Fotokatalis.
This work describes the production photocatalyst in two steps, (1) production of N-CXTi nanocomposites by sol-gel polymerization of resorcinol-formaldehyde-melamine in the presence of K2TiF6 inorganic metallic salt with TiO2 as precursor; (2) Synthesis of the Fe3O4/N-CXTi and Fe3O4/SiO2/N-CXTi nanocomposites by mechanical mixing of N-CXTi and magnetic nanoparticles. The magnetic nanoparticles (Fe3O4 and Fe3O4/SiO2) were prepared by a chemical co-precipitation method and subsequent functionalization by silica (SiO2). The materials were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy, X-ray diffractometry, and textural properties. The composites presented a morphology heterogeneous structure and the presence of two phases for the introduction of TiO2. The region was formed by amorphous carbon and carbon spheres, where Ti is detected only immersed in the amorphous carbon particles, in the anatase and rutile phase, and the presence of magnetic nanoparticles is located surrounded by the carbon structure. Results for the recovery and reuse of the photocatalyst Fe3O4/SiO2/N-CXTi presented the highest efficiency in the removal of the acetaminophen (APP) in the aqueous medium; the result of the reaction carried out in the presence of ultraviolet irradiation showed that the magnetic photocatalyst removed 99.2% of APP in an aqueous medium. Results for the recovery and reuse of the photocatalysts for nine consecutive reactions showed that they can be separated from the reaction medium in a simple and fast way, without significant losses of photocatalytic efficiency and excellent recovery of the photocatalyst.
Earth crust is rich with different materials and their oxides that traditionally have been utilized in numerous applications since the emergence of life on earth. Metal oxides, being the most abundant material of earth crust, have been pivot to the researcher for their unique qualities such as stability, ease of synthesis, superconductivity, colossal magnetoresistance, and structural variety. The implication of metal oxides in glass formation also results in a unique congregation of characteristics such as smaller phonon energy, high refractive index, and transparency in the middle infrared spectrum. In practical applications, dispersive wavelength, mean dispersion, and refractive index play a vital role. These factors determine the feasibility and sustainability of glass. In this regard, metal oxides promise superior properties that become the main incentive for its growth in this field. There are a few parameters that limit the practical applications of metal oxide glasses. In this regard, the low transmission capability, up to 4 μm only, of these metal oxide glasses in the electromagnetic spectrum is a major contributor. Moreover, the glasses of transition metals must possess very high electronic conductivity, but the addition of conventional formers limits it. Transition metal–based glasses have very small capability to form a glass all alone; therefore, formers such as SiO2 are inserted. The addition of impurities allows the formation of glass, but an overall disordered structure is formed. This disordered structure is characterized by a high degree of cation dispersion that disturbs the electron flow and reduces the capability of electronic conductivity. In this chapter, various other factors that limit its industrial implications will also be elaborated. Furthermore, the fabrication process also limits its utilization as an uncontrolled environment may result in unexpected physical properties. Therefore, this chapter sheds light on various fabrication techniques of metal oxides glass formation and also the physical properties of these glasses in terms of their fabrication. In addition, environmental consequences and future aspects of metal oxide glass will also be elaborated.
The development of new effective Fenton-like catalysts is of interest for solving a wide range of problems related to toxic organic pollutants’ destruction in aqueous media. In this chapter, an attempt was made to obtain g-C3N4-MgFe2O4 composites of various structures and morphologies, as well as to justify their effectiveness as Fenton-like catalysts. The prepared composites were characterized by XRD, FTIR, and SEM-EDX methods. It was shown that all composites were characterized by the formation of g-C3N4 with the s-heptazine structure and a different ratio of g-C3N4 and MgFe2O4 on the surface. The catalytic properties of g-C3N4-MgFe2O4 composites in the degradation reaction of the thiazine dye Methylene Blue under various conditions (dark-, visible-, and UV-driven processes), as well as under multiply catalytic cycles, were studied. The most effective sample of composite I under UV irradiation provided 99% Methylene Blue degradation efficiency for 20 min at four cycles. The mechanism of catalytic destruction of Methylene Blue mainly due to the formation of hydroxyl radicals in the reaction mixture was proposed.KeywordsCarbon nitrideMagnesium ferriteNanostructured compositesHeterogeneous fenton catalystsAdvanced oxidation processesMethylene blue degradation
The rising quantity and toxicity of dye-enriched industrial effluents due to rapid industrialization is a foremost and emerging concern throughout the world. The presence of dyes in the waterbodies possesses a threat to aquatic life and can annihilate the environment and human health. Therefore, before discharge, the treatment of dye-contaminated industrial effluents is of paramount importance. Heterogeneous photocatalysis, an advanced oxidation process (AOP), is a sustainable and effective treatment approach that has a greater potential for the catalytic eradication of dyes by generating highly reactive radicals. In general, titanium dioxide (TiO2) semiconductor photocatalyst is extensively used for the photocatalytic degradation of dyes. However, owing to various drawbacks associated with TiO2 photocatalysts such as higher electron–hole pair recombination and larger bandgap, the TiO2 photocatalyst is modified by coupling with carbonaceous materials for higher photocatalytic activity and visible light-harvesting ability. Therefore, this chapter briefly describes the mechanism involved in the photocatalytic degradation of dye and elucidates the different methods for synthesizing carbonaceous-based TiO2 composites comprising activated carbon, graphene derivatives, carbon doping, and carbon nanotubes for dye removal. Also, the chapter precisely focuses on the existing and recent studies on dye removal using carbonaceous-based TiO2 materials. Therefore, this study will be useful for engineers and researchers working in the domain of industrial wastewater treatment.KeywordsPhotocatalysisDye degradationTiO2 photocatalystIndustrial effluentsGraphene oxideCarbon nanotubeActivated carbonDoped carbon
Industrial waste is the primary source of highly toxic organic pollutants and heavy metal contaminants. Treatment of such effluence is necessary to mitigate environmental pollution to provide a clean ecosystem for living species. Various approaches have been effectively utilized for the removal of industrial waste particularly, photocatalysis being an effective, economical, and time-efficient approach to remove toxic ions. Large organic molecules found in pesticides and dyes can be removed with relative ease using nano-photocatalysts with a wide energy band gap, which is one of its major merits. For this purpose, a combination of various metal oxides with relevant materials is generally employed to activate visible regions in photocatalysts. Moreover, modification in physical parameters such as surface area of the catalyst, crystallinity, particle size and morphology, band gap, and microstructure is undertaken, which serves to enhance the photocatalytic activity. Here, advanced techniques that are presently used to synthesize different types of photocatalysts and their potential use in the degradation of the organic dye have been described in detail. The focus of the current review is various metal oxide NPs such as ZnO, TiO2, WO3, SnO2, and CuO with potential applications in photocatalysis, their structural characteristics, classification, and their photocatalytic mechanism. The review covers the influence of dopants on morphological, electrical, optical, and photocatalytic activity of selected nanocomposite systems. Moreover, the current review grasps extensive literature on the role of metal oxides as a photocatalyst that will facilitate researchers by providing guidelines to design more suitable nano-photocatalytic systems.
During this work, the properties of mesoporous titanium oxide were improved by nitrogen and carbon co-doping. The synthesis of C,N-co-doped mesoporous titania was conducted using the in situ via template-guided sol-gel self-assembly method. Chitosan was used as templating agent, but also, to provide the carbon and nitrogen sources for doping. In case of conventional TiO2, F127 was be used as surfactant. All the TiO2 synthesis were Ultrasound (US) assisted, followed by microwaves (MW) thermal treatment, since these processes proved to be time and energy saving. For comparison, conventional thermal treatment was also applied. Some preliminary photodegradation studies were made to investigate whether the conventional and the N, C-co-doped TiO2 are suitable for organic pollutants removal from wastewaters.
In this paper, E-carbon nanotubes were electrochemically assembled into binary TiO2 NTs. The assembled E-carbon nanotube, a nanoantenna for the sensitization of photocatalysis, enables trapping and transferring channels of mass and charge for uniformity and extension of the binary surface of the two-layer TiO2 NTs in the microstructure. Also, the E-carbon nanoantenna is electrojunctionally functionalized for an efficient charge separationone dominated by the photocatalytic process, determined by the effective photocapacitance. The E-carbon nanoantenna exhibited a superior adsorptive capacity to the reactive molecular adsorption—one key photocatalytic process—by increasing the mass transfer. Moreover, cyclic voltammetry of the assembled binary TiO2 NTs covered a large integrated area of the capacitance under UV-light. This characteristic indicated that super-photocapacitance exists in the catalytic system via light irradiation. In light of principles of photovoltage and photocatalysis, the NT features can generate a photovoltage by accelerating the charge separation, prolonging the charge lifetime and decreasing the charge recombination. It is necessary to promote the photocatalysis, as results, that the charges can be moved to the target substances on the surface of TiO2 NTs more quickly, which can greatly alter the photocatalytic process. Raised from the total sensitization, the photocatalysis was significantly enhanced by the exquisitely coupled catalyst system in the efficient NB oxidation increase of 24.5% compared to the unassembled one.
"Space--the final frontier." This preamble to a well-known television series captures the challenge encountered not only in space travel adventures, but also in the field of porous materials, which aims to control the size, shape and uniformity of the porous space and the atoms and molecules that define it. The past decade has seen significant advances in the ability to fabricate new porous solids with ordered structures from a wide range of different materials. This has resulted in materials with unusual properties and broadened their application range beyond the traditional use as catalysts and adsorbents. In fact, porous materials now seem set to contribute to developments in areas ranging from microelectronics to medical diagnosis.
Green titana: Carbon-doped titanium dioxide, supported onto filter paper, photocatalyzes the gas-phase degradation of the atmospheric pollutants benzene (a), acetaldehyde (b) and carbon monoxide
Over the past decades, the tremendous effort put into TiO2 nanomaterials has resulted in a rich database for their synthesis, properties, modifications, and applications. The continuing breakthroughs in the synthesis and modifications of TiO2 nanomaterials have brought new properties and new applications with improved performance. Accompanied by the progress in the synthesis of TiO2 nanoparticles are new findings in the synthesis of TiO2 nanorods, nanotubes, nanowires, as well as mesoporous and photonic structures. Besides the well-know quantum-confinement effect, these new nanomaterials demonstrate size-dependent as well as shape- and structure-dependent optical, electronic, thermal, and structural properties. TiO2 nanomaterials have continued to be highly active in photocatalytic and photovoltaic applications, and they also demonstrate new applications including electrochromics, sensing, and hydrogen storage. This steady progress has demonstrated that TiO2 nanomaterials are playing and will continue to play an important role in the protections of the environment and in the search for renewable and clean energy technologies.
- D M Antonelli
- J Y Ying
D. M. Antonelli, J. Y. Ying, Angew. Chem. Int. Ed. Engl. 34 (1995) 2014-2017.
- P Yang
- D Zhao
- D I Margolese
- B F Chmelka
- G D Stucky
P. Yang, D. Zhao, D. I. Margolese, B. F. Chmelka, G. D. Stucky, Nature 396 (1998) 152-155.
- J Zheng
- J Pang
- K Qiu
- Y Wei
J. Zheng, J. Pang, K. Qiu, Y. Wei, J. Mater. Chem. 11 (2001) 3367-3372.
- D Grosso
- G J De
- A A Soler-Illia
- E L Crepaldi
- F Cagnol
- C Sinturel
- A Bourgeois
- A Brunet-Bruneau
- H Amenitsch
- P A Albouy
- C Sanchez
D. Grosso, G. J. de A. A. Soler-Illia, E.L. Crepaldi, F. Cagnol, C. Sinturel, A. Bourgeois, A. Brunet-Bruneau, H. Amenitsch, P. A. Albouy, C.
Sanchez, Chem. Mater. 15 (2003) 4562-4570.
- L.-H Kao
- T.-C Hsu
- K.-K Cheng
L.-H. Kao, T.-C. Hsu, K.-K. Cheng, J. Colloid Interf. Sci. 341 (2010) 359-365.
- D Grosso
- G J De
- A A Soler-Illia
- F Babonneau
- C Sanchez
- P.-A Albouy
- A Brunet-Bruneau
- A R Balkenende
D. Grosso, G. J. de A. A. Soler-Illia, F. Babonneau, C. Sanchez, P.-A. Albouy, A. Brunet-Bruneau, A. R. Balkenende, Adv. Mater. 13 (2001)
1085-1090.
- W Choi
- A Termin
- M R Hoffmann
W. Choi, A. Termin, M. R. Hoffmann, J. Phys. Chem. 98 (1994) 13669-13679.
- R Asahi
- T Morikawa
- T Ohwaki
- K Aoki
- Y Taga
R. Asahi, T. Morikawa, T. Ohwaki, K. Aoki, Y. Taga, Science 293 (2001) 269-271.
- K S W Sing
- D H Everett
- R A W Haul
- L Moscou
- R A Pierotti
K. S. W. Sing, D. H. Everett, R. A. W. Haul, L. Moscou, R. A. Pierotti, J. Rouquerol, T. Siemieniwska, Pure Appl. Chem. 57 (1985) 603619.
- A C Ferrari
- J Robertson
A. C. Ferrari, J. Robertson, Phys. Rev. B 64 (2001) 075414.
- T Wu
- G Liu
- J Zhao
- H Hidaka
- N Serpone
T. Wu, G. Liu, J. Zhao, H. Hidaka, N. Serpone, J. Phys. Chem. B 102 (1998) 5845-5851.
- Y J Chen
- G Y Jhan
- G L Cai
- C S Lin
- M S Wong
- S.-C Ke
- H H Lo
- C L Cheng
- J.-J Shyue
Y. J. Chen, G. Y. Jhan, G. L. Cai, C. S. Lin, M. S. Wong, S.-C. Ke, H. H. Lo, C. L. Cheng, J.-J. Shyue, J. Vac. Sci. Technol. A 28 (2010)
779-782.
- K S W Sing
- D H Everett
- R A W Haul
- L Moscou
- R A Pierotti
- J Rouquerol
- T Siemieniwska
K. S. W. Sing, D. H. Everett, R. A. W. Haul, L. Moscou, R. A. Pierotti, J. Rouquerol, T. Siemieniwska, Pure Appl. Chem. 57 (1985) 603-619.