Graphene nanoplatelets with low defect density as a synergetic adsorbent and electron sink for ZnO in the photocatalytic degradation of Methylene Blue under UV–vis irradiation

Mahmud, Rabiatul Aliah; Shafawi, Anis Natasha; Ali, Khozema Ahmed; Putri, Lutfi Kurnianditia; Rosli, Noor Izzati Md; Mohamed, Abdul Rahman

doi:10.1016/j.materresbull.2020.110876

Cited by 58 publications

(16 citation statements)

References 83 publications

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“…Conditions such as precursors, concentration of the mixture, reaction temperature, and pressure contribute to deciding the ZnO nanoparticles' dimensions. ZnO/carbon nanocomposites with different ZnO shapes and sizes have been synthesized using hydrothermal [47][48][49] and solvothermal synthesis [50][51][52].…”

Section: Hydrothermal and Solvothermalmentioning

confidence: 99%

“…It is employed for ZnO-graphene composites to verify the ZnO presence and identify functional groups bonded to graphene. The technique is beneficial for revealing the oxygenate groups present in graphene oxide obtained by chemical methods [50,127,128]. The wavenumber is related to the oscillating frequency of molecules or functional groups.…”

Section: Infrared (Ir) Spectroscopymentioning

confidence: 99%

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Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review

et al. 2020

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ZnO is an exciting material for photocatalysis applications due to its high activity, easy accessibility of raw materials, low production costs, and nontoxic. Several ZnO nano and microstructures can be obtained, such as nanoparticles, nanorods, micro flowers, microspheres, among others, depending on the preparation method and conditions. ZnO is a wide bandgap semiconductor presenting massive recombination of the generated charge carriers, limiting its photocatalytic efficiency and stability. It is common to mix it with metal, metal oxide, sulfides, polymers, and nanocarbon-based materials to improve its photocatalytic behavior. Therefore, ZnO–nanocarbon composites formation has been a viable alternative that leads to new, more active, and stable photocatalytic systems. Mainly, graphene is a well-known two-dimensional material, which could be an excellent candidate to hybridize with ZnO due to its excellent physical and chemical properties (e.g., high specific surface area, optical transmittance, and thermal conductivity, among others). This review analyses ZnO–graphene nanocomposites’ recent advances, addressing the synthesis methods and the resulting structural, morphological, optical, and electronic properties. Moreover, we examine the ZnO–graphene composites’ role in the photocatalytic degradation of organic/inorganic pollutants.

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Section: Hydrothermal and Solvothermalmentioning

confidence: 99%

Section: Infrared (Ir) Spectroscopymentioning

confidence: 99%

Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review

et al. 2020

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“…[53,54] Both embedded Ag 2 O and magnetite on the LDH can respond to the visible light by photogeneration of electron-hole pairs, despite the LDH having no electron transfer under visible light. [55][56][57] Meanwhile, some of the photogenerated electrons at the conduction band (CB) energy level of Ag 2 O (+0.2 eV) [58] could transfer to the CB of Hence, ZnAl-LDH as an n-type semiconductor indirectly responds to visible light and transfers the received electron to the dissolved oxygen to form •O 2 À radicals and •OH, respectively, by combining with water. Besides, extra •OH can be released by the reaction between the facial OH À groups on the LDH and produced holes.…”

Section: Investigation Of Photodegradation Mechanismmentioning

confidence: 99%

“…[53,54] Both embedded Ag 2 O and magnetite on the LDH can respond to the visible light by photogeneration of electron-hole pairs, despite the LDH having no electron transfer under visible light. [55][56][57] Meanwhile, some of the photogenerated electrons at the conduction band (CB) energy level of Ag 2 O (+0.2 eV) [58] could transfer to the CB of Fe Besides, extra •OH can be released by the reaction between the facial OH À groups on the LDH and produced holes. [59] Because the CB potential of Ag 2 O (+1.4 eV) [54] is higher than the standard redox potential of •OH/H 2 O (+2.68 eV), [60] the holes on the VB of Ag 2 O cannot produce •OH.…”

Section: Investigation Of Photodegradation Mechanismmentioning

confidence: 99%

Visible light photodegradation of 4‐nitrophenol by new high‐performance and easy recoverable Fe₃O₄/Ag₂O‐LDH hybrid photocatalysts

Dinari

Dadkhah

2021

Applied Organom Chemis

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Till now, water contaminant photodegradation has been the most influential method to remove low but dangerous concentrations of pollutants. Herein, a green method was employed to enhance the photocatalytic activity of ZnAl-LDH through depositing Ag and magnetite nanoparticles on the surface of layered double hydroxide (LDH) sheets. The structural and electrochemical characterization of as-prepared Zn 3 Al-CO 3 (ZA-LDH) and Fe 3 O 4 /Ag 2 O-LDH (M 10 A 5 -LDH) composite was determined by X-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) theory, field emission scanning electron microscopy (FESEM) along with energy-dispersive X-ray spectroscopy (EDX) mapping, UV-vis diffuse reflectance spectra, photoluminescence spectra, and transient photocurrent response. All of the analyses confirmed the photoresponse enhancement of the M 10 A 5 -LDH compared with virgin LDH. The mineralization of p-nitrophenol (PNP) under visible light revealed that the photodegradation rate of composite (0.02 min À1 ) is fourfold more significant than that of the bare ZA-LDH (0.005 min À1 ). The active radical capturing tests exhibited that h + , •OH, and •O 2 À play substantial roles in PNP degradation, respectively. The potential photodegradation mechanism involves the charge transfer from Fe 3 O 4 and Ag 2 O to LDH, producing active radicals for the degradation process. K E Y W O R D S 4-nitrophenol, easy recoverable, Fe 3 O 4 /Ag 2 O-LDH, magnetic nanocomposite, photodegradation | INTRODUCTIONAs the most toxic mono-nitrophenol, 4-nitrophenol (4-NP) is a severe threat to ecological systems, and even 20 mg L À1 of it could raise the risk of cancer. [1] The most common sources of 4-NP in wastewaters are pesticides, medicines, dyes, explosives, leather coloring agents, and plastics. [2,3] It also can deposit in the soil as a hydrolysis product of organophosphorus insecticides like parathion and methyl parathion. [4] To minimize the amount of 4-NP in the environment, many different techniques with chemical, biological, and physical approaches were developed. Even though all the accomplishments have been made using these technologies, high-energy consumption, secondary contamination, and low proficiency are the weaknesses of these methods. Therefore, advanced oxidation processes (AOPs) are introduced as an alternative, which has no harmful product, has no expensive

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“…This novel technique exhibits the advantages of strong oxidizing ability and low cost. Therefore, photocatalytic degradation methods are recommended as environmentally friendly, cheap, and efficient [7,8]. Although the photocatalytic method is costeffective, it has low photocatalytic efficiency.…”

Section: Introductionmentioning

confidence: 99%

Remarkably Enhanced Photodegradation of Organic Pollutants by NH2-UiO-66/ ZnO Composite under Visible-Light Irradiation

Teng¹,

Zhang²,

Luo³

et al. 2022

Journal of Renewable Materials

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Semiconductor photocatalysis is a novel highly efficient and low-cost method for removing organic pollutants from wastewater. However, the photoreduction performance of semiconductors on organic pollutants is limited due to the weak absorption of visible light caused by its wide band gap and low carrier utilization rate resulting from severe electron-holes recombination. In the present study, flower-like NH 2 -UiO-66 (NU66)/ZnO nanocomposites were prepared using a facile method and exhibited high efficiency under visible light driven photocatalysts. The X-ray diffractometer (XRD), scanning electron microscope (SEM), transmitor electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared samples, indicating that NU66/ZnO was successfully synthesized. The photocatalytic activity of the prepared NU66/ZnO nanocomposites was determined by measuring the photodegradation of methylene blue (MB) and malachite green (MG) under visible-light irradiation. The optimal nanocomposite loading of 5% wt NU66 to NU66/ZnO demonstrated the highest photocatalytic activity for the degradation of MB. The photocatalytic activity of a 5% NU66/ZnO composite was approximately 95-fold and 19-fold higher than that of NU66 and ZnO samples, respectively. The enhanced activity of the 5% wt NU66/ZnO nanocomposite was further confirmed through photoelectrochemical analysis. The formation of type II heterojunctions between the counterparts significantly suppressed recombination of the photogenerated charge carriers. Photocatalytic degradation experiments with different quenchers indicated that the effect of superoxide anion radicals (•O 2 − ) had a greater effect than the other scavengers.Additionally, the improved photocatalytic mechanism underlying the activity of NU66/ZnO nanocomposites was also explored. These findings establish a basis for development of MOF based heterojunction for photocatalytic organic pollution remediation.

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Graphene nanoplatelets with low defect density as a synergetic adsorbent and electron sink for ZnO in the photocatalytic degradation of Methylene Blue under UV–vis irradiation

Cited by 58 publications

References 83 publications

Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review

Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review

Visible light photodegradation of 4‐nitrophenol by new high‐performance and easy recoverable Fe₃O₄/Ag₂O‐LDH hybrid photocatalysts

Remarkably Enhanced Photodegradation of Organic Pollutants by NH2-UiO-66/ ZnO Composite under Visible-Light Irradiation

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Graphene nanoplatelets with low defect density as a synergetic adsorbent and electron sink for ZnO in the photocatalytic degradation of Methylene Blue under UV–vis irradiation

Cited by 58 publications

References 83 publications

Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review

Synthesis, Characterization, and Photocatalytic Performance of ZnO–Graphene Nanocomposites: A Review

Visible light photodegradation of 4‐nitrophenol by new high‐performance and easy recoverable Fe3O4/Ag2O‐LDH hybrid photocatalysts

Remarkably Enhanced Photodegradation of Organic Pollutants by NH2-UiO-66/ ZnO Composite under Visible-Light Irradiation

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Visible light photodegradation of 4‐nitrophenol by new high‐performance and easy recoverable Fe₃O₄/Ag₂O‐LDH hybrid photocatalysts