Effect of cobalt doping on the electronic, optical and photocatalytic properties of TiO2

Jiang, Peng; Xiang, Wei; Kuang, Jianlei; Liu, Wenxiu; Cao, Wenbin

doi:10.1016/j.solidstatesciences.2015.05.007

Cited by 69 publications

(52 citation statements)

References 22 publications

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“…Among these preparation methods, hydrothermal synthesis as a well-known preparation method is environmentally friendly because the reaction proceeds in a closed system; the composition of the products is well controlled; and the materials prepared employing this method are well crystallized and have smaller particle size, positively affecting the thermal stability and the photocatalytic activity. For example, Jiang, et al [59] synthesized cobalt-doped TiO 2 by a one-step hydrothermal method for the photodegradation of phenol under visible light. They found that the catalyst doped with 0.3 wt.% shows the highest photocatalytic activity, and they contributed that to the high visible light response by inducing impurity states within its band gap.…”

Section: Introductionmentioning

confidence: 99%

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated by Co-TiO2 Nanoparticles

et al. 2020

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Pharmaceuticals, especially antibiotics, constitute an important group of aquatic contaminants given their environmental impact. Specifically, tetracycline antibiotics (TCs) are produced in great amounts for the treatment of bacterial infections in both human and veterinary medicine. Several studies have shown that, among all antibiotics, oxytetracycline hydrochloride (OTC HCl) is one of the most frequently detected TCs in soil and surface water. The results of the photocatalytic degradation of OTC HCL in aqueous suspensions (30 mg·L−1) of 0.5 wt.% cobalt-doped TiO2 catalysts are reported in this study. The heterogeneous Co-TiO2 photocatalysts were synthesized by two different solvothermal methods. Evonik Degussa Aevoxide P25 and self-prepared TiO2 modified by the same methods were used for comparison. The synthesized photocatalysts were characterized by X-ray powder diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), UV/vis diffuse reflectance spectroscopy (DRS), and N2 adsorption (BET) for specific surface area determination. The XRD and Raman results suggest that Ti4+ was substituted by Co2+ in the TiO2 crystal structure. Uv/visible spectroscopy of Co-TiO2-R showed a substantial redshift in comparison with bare TiO2-R. The photocatalytic performance of the prepared photocatalysts in OTC HCL degradation was investigated employing Uv/vis spectroscopy and high-performance liquid chromatography (HPLC). The observed initial reaction rate over Co-TiO2-R was higher compared with that of Co-TiO2-HT, self-prepared TiO2, and the commercial P25. The enhanced photocatalytic activity was attributed to the high surface area (153 m2·g−1) along with the impurity levels within the band gap (2.93 eV), promoting the charge separation and improving the charge transfer ability. From these experimental results, it can be concluded that Co-doping under reflux demonstrates better photocatalytic performances than with the hydrothermal treatment.

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Section: Introductionmentioning

confidence: 99%

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated by Co-TiO2 Nanoparticles

et al. 2020

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“…Titania synthesized by hydrothermal method usually presents a value around 3.2 eV, not showing visible light absorption. Although a slight decrease of bandgap might be a consequence of cobalt or lanthanum doping, in this case this value drops to 2.88 eV, far from being explained by this effect. Presence of transition metal oxides coating TiO 2 has been reported to shift the bandgap value of TiO 2 .…”

Section: Resultsmentioning

confidence: 59%

“…Cobalt oxides combined with TiO 2 frequently has two bandgaps. 16 consequence of cobalt 15,28 or lanthanum doping, 29 in this case this value drops to 2.88 eV, far from being explained by this effect. Presence of transition metal oxides coating TiO 2 has been reported to shift the bandgap value of TiO 2 .…”

Section: Catalyst Characterizationmentioning

confidence: 70%

Synergism between peroxymonosulfate and LaCoO₃‐TiO₂ photocatalysis for oxidation of herbicides. Operational variables and catalyst characterization assessment

Solís

Rivas

Gimeno

et al. 2017

J of Chemical Tech & Biotech

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BACKGROUND This paper reports the use of novel coupled LaCoO3‐TiO2 as photocatalyst with double route of peroxymonosulfate (PMS) activation. First, as a photocatalyst due to titania; and second, through PMS heterogeneous decomposition onto LaCoO3 particles. Thus, photocatalytical activity was tested for removing a mixture of four herbicides of different recalcitrance (metazachlor, tembotrione, tritosulfuron and ethofumesate). RESULTS The presence of light and PMS highly enhanced herbicides removal rate: 3.5–5 times increases were obtained with UVA light. Oxidant concentration, catalyst load, pH and temperature were assessed. Herbicides were completely oxidized depending on their recalcitrant nature and the operational variables. 55% TOC conversion was reached using Oxone® 5 × 10−4 mol L−1. Phytotoxicity assays denoted no inhibition after 180 min of photocatalytic treatment (∼80% initial inhibition). Solid properties of Co/Ti = 0.1:1 ratio were studied by means of SEM (LaCoO3 aggregates linked to a variety of shapes and sizes of TiO2), XRF (6.1% of LaCoO3), XPS (superficial Co3+, La3+ and Ti4+), XRD (anatase, rutile and rhombohedral LaCoO3) and UV–vis diffuse reflectance (visible range absorption and bandgap of 2.88 eV for TiO2). CONCLUSION Catalysts based on LaCoO3‐TiO2 combined with peroxymonosulfate seem to be suitable for removing organic pollutants, with a moderate conversion of TOC and elimination of toxicity. © 2017 Society of Chemical Industry

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“…Therefore, rutile and brookite phases have not been detected [31,32]. The XRD patterns of Co/TiO 2 samples didn't show any cobalt phase indicating that cobalt ions uniformly dispersed among the anatase crystallites [2,[33][34][35]. Also, the shape of diffraction of pure TiO 2 is quite similar to that of Co/TiO 2 samples.…”

Section: Xrd Analysismentioning

confidence: 99%

“…Besides, high recombination rate of photo-excited carriers is another limitation for the applicable fields of TiO 2 . Due to the short life of photo-excited carriers, only a small part of electrons and vacancies can move to its surface, which lead to further reduction of photocatalytic efficiency [2]. For more than a decade, studies have mainly concentrated on the suspension of TiO 2 fine powder because of its higher photocatalytic activity compared with TiO 2 thin films [3].…”

Section: Introductionmentioning

confidence: 99%

Co/TiO2 nanoparticles: preparation, characterization and its application for photocatalytic degradation of methylene blue

Pirbazari¹,

Monazzam²,

Kisomi³

2018

Preprint

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a b s t r ac tIn this work, TiO 2 nanoparticles containing different amounts of cobalt were synthesized by sol-gel method using titanium (IV) isopropoxide and cobalt chloride as titanium and cobalt precursors, respectively. X-ray diffraction (XRD) results showed prepared samples include 100% anatase phase. The presence of cobalt in TiO 2 nanoparticle network was established by XRD, scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDX), Fourier transform infrared (FT-IR) and N 2 physisorption techniques. The increase of cobalt doping enhanced redshift in the diffuse reflectance spectra. The photocatalytic activity of the prepared samples was tested for degradation of methylene blue (MB) as a model of dye. Although the photocatalytic activity of pure TiO 2 was found to be higher than that of Co/TiO 2 samples under UV irradiation, the presence of 0.24% cobalt dopant in TiO 2 nanoparticles resulted in a photocatalyst with the highest activity under visible light.

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Effect of cobalt doping on the electronic, optical and photocatalytic properties of TiO2

Cited by 69 publications

References 22 publications

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated by Co-TiO2 Nanoparticles

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated by Co-TiO2 Nanoparticles

Synergism between peroxymonosulfate and LaCoO₃‐TiO₂ photocatalysis for oxidation of herbicides. Operational variables and catalyst characterization assessment

Co/TiO2 nanoparticles: preparation, characterization and its application for photocatalytic degradation of methylene blue

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Effect of cobalt doping on the electronic, optical and photocatalytic properties of TiO2

Cited by 69 publications

References 22 publications

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated by Co-TiO2 Nanoparticles

UV/Vis Light Induced Degradation of Oxytetracycline Hydrochloride Mediated by Co-TiO2 Nanoparticles

Synergism between peroxymonosulfate and LaCoO3‐TiO2 photocatalysis for oxidation of herbicides. Operational variables and catalyst characterization assessment

Co/TiO2 nanoparticles: preparation, characterization and its application for photocatalytic degradation of methylene blue

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Synergism between peroxymonosulfate and LaCoO₃‐TiO₂ photocatalysis for oxidation of herbicides. Operational variables and catalyst characterization assessment