Improved Hg2+ photocatalytic reduction over g-C3N4 nanosheets decorated with mesoporous Mn3O4 nanoparticles

2021 ◽  
Vol 11 (5) ◽  
pp. 688-698
Author(s):  
Maha Alhaddad ◽  
M. H. H. Mahmoud
Keyword(s):  
Visible Light ◽  
Surface Area ◽  
Spherical Shape ◽  
Complete Removal ◽  
Mesoporous Structure ◽  
Light Illumination ◽  
Morphological Examination ◽  
Particle Dimension ◽  
Visible Light Illumination ◽  
Mn3o4 Nanoparticles

The purpose of this investigation was to construct amended mesoporous Mn3O4/g-C3 N4 photocatalysts of various loadings of mesoporous Mn3O4 nanoparticles (1,2,3 and 4 wt%) for reinforced remediation of mercury ions (Hg2+) under visible light illumination. It was performed via decorating g-C3N4 nanosheets with finite portions of the prepared mesoporous Mn3O4 NPs by employing hard and soft templates. The optimized 3 wt% Mn3O4/g-C3N4 heterojunction gained confined bandgap (2.24 eV) as well as great surface area (140 m2 g -1) that support the application of such heterojunction for efficacious removal of Hg2+ under visible light. Morphological examination elucidated that the dispersed Mn3O4 NPs over g-C3N4 nanosheets were of spherical shape with particle dimension of 10-15 nm. Hg2+ was removed significantly over the formed Mn3O4/g-C3N4 nanocomposites when related to the pure materials (Mn3O4 NPs and g-C3N4). It was confirmed that Mn3O4 content, incorporated to g-C3N4 nanosheets, largely influenced the efficiency corresponding to the Hg2+ photoreduction such that appropriating 3 wt% Mn3O4 was capable of accomplishing complete removal of Hg2+ whereas, pure g-C3N 4was able to accomplish the same process by the efficiency of 15% after illumination for 60 min. Similarly, fast rate of Hg2+ photoreduction was accessed when 3% Mn3O4/g-C3N4 nanocomposite (485 µmol g–1 h–1) was administered while the photoreduction reaction was very slow with smaller rate magnitudes when pure g-C3N 4(82 µmol g -1 h -1) or pure Mn3O4 NPs (120 µmol g -1 h -1) were adopted. The powerful Hg2+ removal over the established heterojunctions can basically be associated with the larger attained surface area as well as the declined bandgap. Besides, the great dispersion of the small-sized Mn3O4 NPs and the mesoporous structure of the formed heterojunctions participated significantly in efficient Hg2+ removal. The improved characteristics of the prepared heterojunctions led to strong absorption of visible light and fast transference of reactant species, leading to enhanced photocatalytic efficiency. Recyclability experiments demonstrated that neither the photocatalytic performance nor the structure of the mesoporous Mn3O4/g-C3N4 heterojunction was altered after being reused for Hg2+ removal from aqueous solutions.

scholarly journals Sunlight-Active BiOI Photocatalyst as an Efficient Adsorbent for the Removal of Organic Dyes and Antibiotics from Aqueous Solutions

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5624
Author(s):  
Teerapong Narenuch ◽  
Teeradech Senasu ◽  
Tammanoon Chankhanittha ◽  
Suwat Nanan
Keyword(s):  
Visible Light ◽  
High Efficiency ◽  
Organic Dyes ◽  
High Surface ◽  
High Surface Area ◽  
Complete Removal ◽  
Light Illumination ◽  
Visible Light Illumination ◽  
Key Factor ◽  
High Structural Stability

A bismuth oxyiodide (BiOI) photocatalyst with excellent sunlight-driven performance was synthesized by a solvothermal route without the addition of surfactants or capping agents. The prepared photocatalyst exhibited a tetragonal phase with an energy band gap of 2.15 eV. The efficiency of the photocatalyst was elucidated by monitoring the photodegradation of organic dyes and antibiotics. The BiOI photocatalyst provided a 95% removal of norfloxacin (NOR) antibiotics under visible light illumination. Interestingly, the complete removal of Rhodamine B (RhB) dye was achieved after 80 min of natural sunlight irradiation. The photodegradation reaction followed the first-order reaction. Both photo-generated holes and electrons play vital roles in the photodegradation of the pollutant. The BiOI photocatalyst remains stable and still shows a high efficiency even after the fifth run. This confirms the great cycling ability and high structural stability of the photocatalyst. The prepared BiOI catalyst, with a high surface area of 118 m2 g−1, can act as an excellent adsorbent as well. The synergistic effect based on both adsorption and photocatalysis is a key factor in achieving a very high removal efficiency. The photoactivity under sunlight is higher than that observed under visible light, supporting the practical use of the BiOI photocatalyst for the removal of organic pollutants in wastewater through the utilization of abundant solar energy.

Photoelectrocatalytic Oxidation of Organics Under Visible Light Illumination: A Short Review

2015 ◽  
Vol 19 (6) ◽  
pp. 512-520 ◽  
Author(s):  
Nikolaos Karanasios ◽  
Jenia Georgieva ◽  
Eugenia Valova ◽  
Stephan Armyanov ◽  
Georgios Litsardakis ◽  
...  
Keyword(s):  
Visible Light ◽  
Short Review ◽  
Light Illumination ◽  
Photoelectrocatalytic Oxidation ◽  
Visible Light Illumination ◽  
Oxidation Of Organics

scholarly journals Enhanced Visible-Light Photocatalytic Performance of SAPO-5-Based g-C3N4 Composite for Rhodamine B (RhB) Degradation

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3948
Author(s):  
Lingfang Qiu ◽  
Zhiwei Zhou ◽  
Mengfan Ma ◽  
Ping Li ◽  
Jinyong Lu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Redox Reactions ◽  
Photocatalytic Performance ◽  
Dye Degradation ◽  
Thermal Polymerization ◽  
Light Illumination ◽  
Electron Hole ◽  
Visible Light Illumination ◽  
Visible Light Photocatalytic

Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4 composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4 is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4 composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min−1 to 0.022 min−1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4 to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4 efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4 and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4 efficiently, but also broadens the application of SAPOs in the photocatalytic field.

scholarly journals Hybrid ZnO/MoS2 Core/Sheath Heterostructures for Photoelectrochemical Water Splitting

Applied Nano ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 148-161
Author(s):  
Katerina Govatsi ◽  
Aspasia Antonelou ◽  
Labrini Sygellou ◽  
Stylianos G. Neophytides ◽  
Spyros N. Yannopoulos
Keyword(s):  
Visible Light ◽  
Wide Band ◽  
Nanowire Arrays ◽  
Maximum Efficiency ◽  
Light Illumination ◽  
Wide Band Gap ◽  
Long Term Stability ◽  
Visible Light Illumination ◽  
Nanowire Surface ◽  
Wide Range

The rational synthesis of semiconducting materials with enhanced photoelectrocatalytic efficiency under visible light illumination is a long-standing issue. ZnO has been systematically explored in this field, as it offers the feasibility to grow a wide range of nanocrystal morphology; however, its wide band gap precludes visible light absorption. We report on a novel method for the controlled growth of semiconductor heterostructures and, in particular, core/sheath ZnO/MoS2 nanowire arrays and the evaluation of their photoelectrochemical efficiency in oxygen evolution reaction. ZnO nanowire arrays, with a narrow distribution of nanowire diameters, were grown on FTO substrates by chemical bath deposition. Layers of Mo metal at various thicknesses were sputtered on the nanowire surface, and the Mo layers were sulfurized at low temperature, providing in a controlled way few layers of MoS2, in the range from one to three monolayers. The heterostructures were characterized by electron microscopy (SEM, TEM) and spectroscopy (XPS, Raman, PL). The photoelectrochemical properties of the heterostructures were found to depend on the thickness of the pre-deposited Mo film, exhibiting maximum efficiency for moderate values of Mo film thickness. Long-term stability, in relation to similar heterostructures in the literature, has been observed.

visible light illumination assistant Li-O2 battery based on an oxygen vacancy doped TiO2 catalyst

2021 ◽  
pp. 139794
Author(s):  
Li Zhang ◽  
Xiaoming Bai ◽  
Gunagyu Zhao ◽  
Xiaojie Shen ◽  
Yufei Liu ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Visible Light ◽  
Light Illumination ◽  
Doped Tio2 ◽  
Tio2 Catalyst ◽  
Visible Light Illumination

scholarly journals A visible-light-controlled platform for prolonged drug release based on Ag-doped TiO2 nanotubes with a hydrophobic layer

2018 ◽  
Vol 9 ◽  
pp. 1793-1801 ◽  
Author(s):  
Caihong Liang ◽  
Jiang Wen ◽  
Xiaoming Liao
Keyword(s):  
Drug Release ◽  
Visible Light ◽  
Controlled Drug Release ◽  
Photocatalytic Decomposition ◽  
Light Illumination ◽  
Visible Light Illumination ◽  
Delivery Platform ◽  
Promising Application ◽  
Hydrophobic Layer ◽  
Prolonged Drug Release

In this work, a visible-light-controlled drug release platform was constructed for localized and prolonged drug release based on two-layer titania nanotubes (TNTs) fabricated using by an in situ voltage up-anodization process. The visible-light photocatalytic activity is improved by loading Ag onto the TNTs by NaBH4 reduction. Then, the TNTs containing Ag nanoparticles were modified with dodecanethiol (NDM) to create a hydrophobic layer. To demonstrate the visible-light-controlled drug release, the Zn2+ release behavior of the samples was investigated. In the initial 12 h, TNTs without NDM displayed a faster release rate with 29.4% Zn2+ release, which was more than three times that of the TNTs with NDM (8.7% Zn2+ release). Upon visible-light illumination, drug release from the sample coated with NDM was shown to increase due to the photocatalytic decomposition of NDM. The amount of released Zn2+ for this sample increased up to 71.9% within 12 h, indicating visible-light-controlled drug release. This drug release system may exhibit promising application as a localized, prolonged drug delivery platform.

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