Synthesis and Characterization of Mesoporous Nb<sub>2</sub>O<sub>5</sub>and Its Application for Photocatalytic Degradation of the Herbicide Methylviologen

Castro, Douclasse C. de; Cavalcante, Rodrigo Pereira; Jorge, Juliana; Martines, Marco Antônio Utrera; Oliveira, Lincoln Carlos Silva de; Casagrande, Gleison A.; Machulek, Amílcar

doi:10.5935/0103-5053.20150244

Cited by 17 publications

(16 citation statements)

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“…Among the most promising photocatalysts is niobium pentoxide (Nb 2 O 5 ), with excellent chemical and photochemical stability, and it has been tested for reactions such as the photocatalytic degradation of organic pollutants, photocatalytic selective oxidation of benzylamine, and water splitting to produce hydrogen . However, owing to the high recombination rate of photogenerated electron–hole pairs, the photocatalytic activity of Nb 2 O 5 is rather limited.…”

Section: Introductionmentioning

confidence: 99%

One‐Step Synthesis of Nb₂O₅/C/Nb₂C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

et al. 2018

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Hydrogen production through facile photocatalytic water splitting is regarded as a promising strategy to solve global energy problems. Transition-metal carbides (MXenes) have recently drawn attention as potential co-catalyst candidates for photocatalysts. Here, we report niobium pentoxide/carbon/niobium carbide (MXene) hybrid materials (Nb O /C/Nb C) as photocatalysts for hydrogen evolution from water splitting. The Nb O /C/Nb C composites were synthesized by one-step CO oxidation of Nb CT . Nb O grew homogeneously on Nb C after mild oxidation, during which some amorphous carbon was also formed. With an optimized oxidation time of 1.0 h, Nb O /C/Nb C showed the highest hydrogen generation rate (7.81 μmol h g ), a value that was four times higher than that of pure Nb O . The enhanced performance of Nb O /C/Nb C was attributed to intimate contact between Nb O and conductive Nb C and the separation of photogenerated charge carriers at the Nb O /Nb C interface; the results presented herein show that transition-metal carbide are promising co-catalysts for photocatalytic hydrogen production.

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Section: Introductionmentioning

confidence: 99%

One‐Step Synthesis of Nb₂O₅/C/Nb₂C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

et al. 2018

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“…10,11 Heterogeneous photocatalysis using TiO 2 has received considerable attention as an AOP for photodegradation of organic pollutants in water. [12][13][14][15] Despite being a promising technology, photocatalysis with TiO 2 has disadvantages, including low degradation kinetics and a high probability of electron-hole recombination. Removal of catalysts at the end of the process is a major requirement in photocatalysis, albeit one difficult to meet, as it involves a solid-liquid separation step that adds to the overall capital and running costs in WWTPs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Photocatalytic Activity of Pure and N-, B-, or Ag- Doped TiO2

Bezerra¹,

Cavalcante²,

Garcia³

et al. 2017

J. Braz. Chem. Soc.

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This article reports the synthesis and characterization of pure and N-, B-, and Ag-doped TiO 2 and the ability of these oxides to photodegrade methylene blue (MB) under sunlight or UV-ABC radiation. The compounds were synthesized using the sol-gel method and characterized by scanning electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Photocatalytic efficiency was significantly increased by N-doping, resulting in 98% MB decomposition under UV-ABC irradiation for 180 min. Ag-and B-doped TiO 2 lowered MB degradation rates to 52 and 73%, respectively, compared with pure TiO 2 . The same behavior was observed with exposure to UV-Vis, with 88, 65, 60, and 42% MB removal with N-doped, pure, B-doped, and Ag-doped TiO 2 , respectively. Under visible light alone, N-doped TiO 2 exhibited higher photocatalytic efficiency than commercial P25-type TiO 2 . Photocatalysis with N-doped TiO 2 proved to be a promising alternative for MB degradation, given the potential of employing solar energy, thus minimizing operating costs.

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“…Heterogeneous photocatalysis (HPC) is another branch of AOPs used in the degradation of contaminants. This technique uses transition metal oxides and sulfides, mainly titanate (TiO 2 ), zinc oxide (ZnO), zinc sulfide (ZnS), among others, as photosensitizers in photoinduced processes, as they have semi-filled valence band structures and empty conduction band (Castro et al, 2016). In addition, semiconductors through ultraviolet irradiation favor the displacement of electrons from the valence to the conduction band, originating hydroxyl radicals for deteriorating pollutant compounds (Santos et al, 2015a).…”

Section: Heterogeneous Photocatalysismentioning

confidence: 99%

“…However, recovering semiconductors to be reused is difficult and laborious. Another disadvantage of the heterogeneous photocatalysis is that its performance depends on the adsorption, morphology, surface, structure, particle size, among other characteristics of the used compound (Castro et al, 2016). Xu et al (2011) assessed the use of the Fe 3 O 4 /SiO 2 /TiO 2 photocatalysis system in the decontamination of a soil polluted with glyphosate.…”

Section: Heterogeneous Photocatalysismentioning

confidence: 99%

Remediation of Soils Contaminated by Pesticides Using Physicochemical Processes: a Brief Review

et al. 2019

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After years of pesticide application, often indiscriminately, damage has been caused to the environment, as well as to agronomic crops grown in contaminated areas. In water treatment, techniques based on physical and/or physicochemical processes are used, being formed secondary oxidizing agents responsible for the mineralization of contaminants present in the herbicides, thus causing the degradation process. However, few studies have demonstrated the effectiveness of these techniques in soils. The aim of this study was to review the existing studies, presenting the main techniques used for remediation of soils contaminated with pesticides. Emphasis was placed on electrokinetics, advanced oxidative processes, soil washing, chemical or solvent extraction, and combinations of these methods. According to the results of several studies, the combination of techniques, such as electrokinetics and soil washing processes, allows achieving a high efficiency when it is applied for the degradation of agricultural contaminants. The combination of electrolysis with other methods, such as the Fenton’s reagent, ultrasound irradiation, and UV light, also present satisfactory results in removing pesticides in soil treatment. However, Fenton technology used alone is the most promising of the assessed techniques since it can be used for the remediation of several contaminants, especially pesticides, not harming the environment and allowing soil recovery.

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Synthesis and Characterization of Mesoporous Nb₂O₅and Its Application for Photocatalytic Degradation of the Herbicide Methylviologen

Cited by 17 publications

References 1 publication

One‐Step Synthesis of Nb₂O₅/C/Nb₂C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

One‐Step Synthesis of Nb₂O₅/C/Nb₂C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

Synthesis, Characterization, and Photocatalytic Activity of Pure and N-, B-, or Ag- Doped TiO2

Remediation of Soils Contaminated by Pesticides Using Physicochemical Processes: a Brief Review

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Synthesis and Characterization of Mesoporous Nb2O5and Its Application for Photocatalytic Degradation of the Herbicide Methylviologen

Cited by 17 publications

References 1 publication

One‐Step Synthesis of Nb2O5/C/Nb2C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

One‐Step Synthesis of Nb2O5/C/Nb2C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

Synthesis, Characterization, and Photocatalytic Activity of Pure and N-, B-, or Ag- Doped TiO2

Remediation of Soils Contaminated by Pesticides Using Physicochemical Processes: a Brief Review

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Synthesis and Characterization of Mesoporous Nb₂O₅and Its Application for Photocatalytic Degradation of the Herbicide Methylviologen

One‐Step Synthesis of Nb₂O₅/C/Nb₂C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

One‐Step Synthesis of Nb₂O₅/C/Nb₂C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution