scholarly journals Core-Shell Nanostructures of Graphene-Wrapped CdS Nanoparticles and TiO2 (CdS@G@TiO2): The Role of Graphene in Enhanced Photocatalytic H2 Generation

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 358 ◽  
Author(s):  
Muhammad Zubair ◽  
Ingeborg-Helene Svenum ◽  
Magnus Rønning ◽  
Jia Yang
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Quantum Dots ◽  
Pure Tio2 ◽  
Cds Nanoparticles ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Tio2 Sample ◽  
Simulated Solar Light ◽  
Shell Nanostructures ◽  
Tio2 Shell

Aiming to achieve enhanced photocatalytic activity and stability toward the generation of H2 from water, we have synthesized noble metal-free core-shell nanoparticles of graphene (G)-wrapped CdS and TiO2 (CdS@G@TiO2) by a facile hydrothermal method. The interlayer thickness of G between the CdS core and TiO2 shell is optimized by varying the amount of graphene quantum dots (GQD) during the synthesis procedure. The most optimized sample, i.e., CdS@50G@TiO2 generated 1510 µmole g−1 h−1 of H2 (apparent quantum efficiency (AQE) = 5.78%) from water under simulated solar light with air mass 1.5 global (AM 1.5G) condition which is ~2.7 times and ~2.2 time superior to pure TiO2 and pure CdS respectively, along with a stable generation of H2 during 40 h of continuous operation. The increased photocatalytic activity and stability of the CdS@50G@TiO2 sample are attributed to the enhanced visible light absorption and efficient charge separation and transfer between the CdS and TiO2 due to incorporation of graphene between the CdS core and TiO2 shell, which was also confirmed by UV-vis, photoelectrochemical and valence band XPS measurements.

scholarly journals Effect of calcination atmosphere on structural, optical and photocatalytic activity of TiO2/SnS2 core-shell nanostructures in the reduction of aqueous Cr(VI) to Cr(III)

2021 ◽  
Vol 15 (1) ◽  
pp. 58-68
Author(s):  
Shalini Sikdar ◽  
Tiju Thomas ◽  
Rao Ramachandra ◽  
Subramshu Bhattacharya
Keyword(s):  
Photocatalytic Activity ◽  
Single Step ◽  
Visible Range ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Shell Nanostructures ◽  
Important Means ◽  
Calcination Atmosphere ◽  
Core Shell Nanoparticles

Conversion of Cr(VI) to Cr(III) in mitigating pollution of water bodies is of significant importance to public health due to the fact that Cr(VI) is known to be a potent carcinogen, while Cr(III) is relatively low in toxicity. Photocatalytic approaches are considered as important means to achieve this reduction. Here, TiO2/SnS2 core-shell nanostructures have been produced using a single-step hydrothermal method and its photocatalytic activity is tested for the reduction of aqueous Cr(VI). The structural and optical properties of the as-synthesized products are characterized by XRD, HRTEM, Raman, FTIR, XPS and DRS techniques. The present work reveals that by calcining the core-shell nanoparticles in Ar atmosphere a defective Ti3O5 phase is formed as the core with low band gap, and hence, offers improved light absorption in the visible range. However, its photoactivity was found to be lower than that of the core-shell nanoparticles annealed in oxidizing atmosphere. The observed lower photoreduction was due to the presence of midgap states which acted as recombination centres and hence, reduced the photocatalytic activity.

scholarly journals Iron Based Core-Shell Structures as Versatile Materials: Magnetic Support and Solid Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 72
Author(s):  
Christian Zambrzycki ◽  
Runbang Shao ◽  
Archismita Misra ◽  
Carsten Streb ◽  
Ulrich Herr ◽  
...  
Keyword(s):  
Water Purification ◽  
Functional Materials ◽  
Core Material ◽  
Solid Catalyst ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
The Core ◽  
Shell Nanostructures ◽  
Sio2 Shell ◽  
Iron Based

Core-shell materials are promising functional materials for fundamental research and industrial application, as their properties can be adapted for specific applications. In particular, particles featuring iron or iron oxide as core material are relevant since they combine magnetic and catalytic properties. The addition of an SiO2 shell around the core particles introduces additional design aspects, such as a pore structure and surface functionalization. Herein, we describe the synthesis and application of iron-based core-shell nanoparticles for two different fields of research that is heterogeneous catalysis and water purification. The iron-based core shell materials were characterized by transmission electron microscopy, as well as N2-physisorption, X-ray diffraction, and vibrating-sample magnetometer measurements in order to correlate their properties with the performance in the target applications. Investigations of these materials in CO2 hydrogenation and water purification show their versatility and applicability in different fields of research and application, after suitable individual functionalization of the core-shell precursor. For design and application of magnetically separable particles, the SiO2 shell is surface-functionalized with an ionic liquid in order to bind water pollutants selectively. The core requires no functionalization, as it provides suitable magnetic properties in the as-made state. For catalytic application in synthesis gas reactions, the SiO2-stabilized core nanoparticles are reductively functionalized to provide the catalytically active metallic iron sites. Therefore, Fe@SiO2 core-shell nanostructures are shown to provide platform materials for various fields of application, after a specific functionalization.

scholarly journals Surface plasmon-driven photocatalytic activity of Ni@NiO/NiCO3 core–shell nanostructures

RSC Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 2733-2743
Author(s):  
Parisa Talebi ◽  
Harishchandra Singh ◽  
Ekta Rani ◽  
Marko Huttula ◽  
Wei Cao
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Surface Plasmon ◽  
Core Shell ◽  
Plasmonic Resonance ◽  
Surface Plasmonic Resonance ◽  
Shell Nanostructures

Surface plasmonic resonance enabled Ni@NiO/NiCO3 core–shell nanostructures as promising photocatalysts for hydrogen evolution under visible light.

One-pot synthesis of CdS@Nb2O5 core–shell nanostructures with enhanced photocatalytic activity

2014 ◽  
Vol 152-153 ◽  
pp. 403-412 ◽  
Author(s):  
Luiz C.A. Oliveira ◽  
Henrique S. Oliveira ◽  
Giovanna Mayrink ◽  
Herman S. Mansur ◽  
Alexandra A.P. Mansur ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Core Shell ◽  
One Pot ◽  
One Pot Synthesis ◽  
Shell Nanostructures

scholarly journals Core@shell Nanoparticles: Greener Synthesis Using Natural Plant Products

2018 ◽  
Vol 8 (3) ◽  
pp. 411 ◽  
Author(s):  
Mehrdad Khatami ◽  
Hajar Alijani ◽  
Meysam Nejad ◽  
Rajender Varma
Keyword(s):  
Large Scale ◽  
Hybrid Nanoparticles ◽  
Target Cells ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Environmental Friendliness ◽  
Shell Nanostructures ◽  
Greener Synthesis ◽  
Core Shell Nanoparticles ◽  
Synthesis Of Nanostructures

Among an array of hybrid nanoparticles, core-shell nanoparticles comprise of two or more materials, such as metals and biomolecules, wherein one of them forms the core at the center, while the other material/materials that were located around the central core develops a shell. Core-shell nanostructures are useful entities with high thermal and chemical stability, lower toxicity, greater solubility, and higher permeability to specific target cells. Plant or natural products-mediated synthesis of nanostructures refers to the use of plants or its extracts for the synthesis of nanostructures, an emerging field of sustainable nanotechnology. Various physiochemical and greener methods have been advanced for the synthesis of nanostructures, in contrast to conventional approaches that require the use of synthetic compounds for the assembly of nanostructures. Although several biological resources have been exploited for the synthesis of core-shell nanoparticles, but plant-based materials appear to be the ideal candidates for large-scale green synthesis of core-shell nanoparticles. This review summarizes the known strategies for the greener production of core-shell nanoparticles using plants extract or their derivatives and highlights their salient attributes, such as low costs, the lack of dependence on the use of any toxic materials, and the environmental friendliness for the sustainable assembly of stabile nanostructures.

UV photocatalytic activity of Au@ZnO core–shell nanostructure with enhanced UV emission

RSC Advances ◽  
2015 ◽  
Vol 5 (80) ◽  
pp. 65595-65599 ◽  
Author(s):  
Tingting Jiang ◽  
Xueying Qin ◽  
Ye Sun ◽  
Miao Yu
Keyword(s):  
Electron Transfer ◽  
Photocatalytic Activity ◽  
Photocatalytic Properties ◽  
Core Shell ◽  
Shell Nanostructures ◽  
Uv Emission

Au@ZnO core–shell nanostructures with increased ultraviolet photoluminescence emissions present remarkably enhanced ultraviolet photocatalytic properties, based on bidirectional electron transfer between Au and ZnO.

scholarly journals Lead-Free BNT–BT0.08/CoFe2O4 Core–Shell Nanostructures with Potential Multifunctional Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 672
Author(s):  
Marin Cernea ◽  
Roxana Radu ◽  
Harvey Amorín ◽  
Simona Gabriela Greculeasa ◽  
Bogdan Stefan Vasile ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
Transmission Electron Microscopy Data ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Two Phase ◽  
X Ray ◽  
Shell Nanostructures

Herein we report on novel multiferroic core–shell nanostructures of cobalt ferrite (CoFe2O4)–bismuth, sodium titanate doped with barium titanate (BNT–BT0.08), prepared by a two–step wet chemical procedure, using the sol–gel technique. The fraction of CoFe2O4 was varied from 1:0.5 to 1:1.5 = BNT–BT0.08/CoFe2O4 (molar ratio). X–ray diffraction confirmed the presence of both the spinel CoFe2O4 and the perovskite Bi0.5Na0.5TiO3 phases. Scanning electron microscopy analysis indicated that the diameter of the core–shell nanoparticles was between 15 and 40 nm. Transmission electron microscopy data showed two–phase composite nanostructures consisting of a BNT–BT0.08 core surrounded by a CoFe2O4 shell with an average thickness of 4–7 nm. Cole-Cole plots reveal the presence of grains and grain boundary effects in the BNT–BT0.08/CoFe2O4 composite. Moreover, the values of the dc conductivity were found to increase with the amount of CoFe2O4 semiconductive phase. Both X-ray photoelectron spectroscopy (XPS) and Mössbauer measurements have shown no change in the valence of the Fe3+, Co2+, Bi3+ and Ti4+ cations. This study provides a detailed insight into the magnetoelectric coupling of the multiferroic BNT–BT0.08/CoFe2O4 core–shell composite potentially suitable for magnetoelectric applications.

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