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Jinendra U, Nagabhushana BM, Bilehal D, Iqbal M, Amachawadi RG, Shivamallu C, Kollur SP. Encapsulated Co-ZnO nanospheres as degradation tool for organic pollutants: Synthesis, morphology, adsorption and photo luminescent investigations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 299:122879. [PMID: 37201331 DOI: 10.1016/j.saa.2023.122879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/12/2023] [Accepted: 05/11/2023] [Indexed: 05/20/2023]
Abstract
Zinc oxide (ZnO) nanostructures, both undoped and Co-doped, were synthesized through the solution combustion process. The diffraction patterns from powder XRD revealed that the materials were crystalline. The morphology of the spherically formed nanoparticles was visualized in SEM micrographs. FTIR spectra verified the existence of a defect-associated peak in Co-encapsulated ZnO (Zn0.98Co0.02O) NPs. Photoluminescence studies are undertaken. Malachite Green (MG) dye is used as a representative organic pollutant to study the adsorptive degradation of Co-doped ZnO nanomaterial. Moreover, the adsorption properties, including isotherm and kinetics, are investigated by analyzing the degradation of MG dye. Experimental parameters, such as the concentration of the MG dye, dosage and pH, were varied to ascertain favorable conditions for the degradation study. The results indicate that the MG dye is 70% degraded. After Co-doping, near-band edge emission in undoped ZnO changed into intense red defect emission and was directly correlated with changes in PL emission.
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Affiliation(s)
- Usha Jinendra
- Department of Chemistry, Karnataka University, Dharwad 560008, Karnataka, India
| | - B M Nagabhushana
- Department of Chemistry, MSRIT, Bengaluru 560 054, Karnataka, India
| | - Dinesh Bilehal
- Department of Chemistry, Karnataka University, Dharwad 560008, Karnataka, India.
| | - Muzaffar Iqbal
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Raghavendra G Amachawadi
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606, USA
| | - Chandan Shivamallu
- Department of Biotechnology and Bioinformatics, JSS Academy of Higher Education and Research, Mysuru, Karnataka 570 015, India
| | - Shiva Prasad Kollur
- School of Physical Sciences, Amrita Vishwa Vidyapeetham, Mysuru Campus, Mysuru, Karnataka 570 026, India.
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Singh K, Kaur H, Sharma PK, Singh G, Singh J. ZnO and cobalt decorated ZnO NPs: Synthesis, photocatalysis and antimicrobial applications. CHEMOSPHERE 2023; 313:137322. [PMID: 36427583 DOI: 10.1016/j.chemosphere.2022.137322] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/31/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Abstract
The rapid growth of pollutants, both biological and non-biological, puts environmental systems in jeopardy. In view of this, the current study demonstrates the synthesis of undoped and Cobalt-doped zinc oxide nanoparticles (Co doped ZnO NPs) via co-precipitation method. The confirmation of incorporation of the Co dopant into ZnO NPs was verified through various spectroscopic and microscopic techniques. UV-absorption spectra of cobalt-doped ZnO NPs revealed a red shift with change of absorption spectra from 356 nm to 377 nm as compared to undoped ZnO NPs. XRD studies inferred that the average crystallite size of 0.5% and 1% Co-doped ZnO powder was obtained to be ∼16 nm and 14 nm respectively. A drop in band gap value from 3.48 eV to 3.30 eV provided as substantive evidence of the successful integration of Co2+ ions inside the ZnO matrix. FESEM and HRTEM studies revealed that the obtained ZnO NPs are in narrow size distribution (15-20 nm) with a wurtzite crystal structure. The synthesized ZnO and Co-ZnO NPs showed excellent photocatalytic and antimicrobial potency towards reactive brown dye (RB-1) and two bacterial strains, respectively. 1% Co-doped ZnO demonstrated the maximum photocatalytic activity (∼95%), in contrast to 0.5% Co-doped ZnO and undoped ZnO. Thus, the findings of this work support the developed system has a dual role as the photocatalyst, and antibacterial agent for efficient environmental remediation.
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Affiliation(s)
- Karanpal Singh
- Department of Electronics Engineering, Sri Guru Granth Sahib World University, Fatehgarh Sahib, 140406, Punjab, India
| | - Harpreet Kaur
- Department of Physics, Sri Guru Granth Sahib World University, Fatehgarh Sahib, 140406, Punjab, India
| | - Pushpender Kumar Sharma
- Amity Institute of Biotechnology, Amity University Rajasthan, Jaipur, 303002, Rajasthan, India
| | - Gurjinder Singh
- Department of Electronics Engineering, Sri Guru Granth Sahib World University, Fatehgarh Sahib, 140406, Punjab, India.
| | - Jagpreet Singh
- Department of Chemical Engineering, University Centre for Research and Development, Chandigarh University, Gharuan Mohali, 140413, Punjab, India.
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Karuppaiah B, Jeyaraman A, Chen SM, Chavan PR, Karthik R, Hasan M, Shim JJ. Effect of bismuth doping on zircon-type gadolinium vanadate: Effective electrocatalyst for determination of hazardous herbicide mesotrione. CHEMOSPHERE 2023; 313:137543. [PMID: 36535502 DOI: 10.1016/j.chemosphere.2022.137543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/29/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
Pesticides are used to promote the growth of plants and crops by killing weeds and other pests. On the other hand, overused and unused pesticides can leach into groundwater and agricultural lands, easily contaminating water, air, and soil resources. Doping with metal ions is an effective method to improve the catalytic activity of potential electrode materials. In the present study, an electrochemical sensor based on Bi3+-doped gadolinium vanadate nanoparticles (GVB NPs) was fabricated for sensitive and selective detection of harmful pesticide mesotrione (MST). The crystalline nature, functional groups, and elemental composition of the prepared electrocatalysts were confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Field-emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) showed that the undoped gadolinium vanadate had a rice-like nanostructure and was designated as GV NRs, while GVB had the morphology of nanoparticles. The fabricated electrode exhibited a well-resolved MST reduction peak in cyclic voltammetry and linear sweep voltammetry (LSV). Bismuth doping effectively enhanced the MST reduction and produced a stronger cathodic current response than bare and GV NRs-modified GCE. Moreover, GVB NPs/GCE show a nanomolar detection limit of 45 nM with a sensitivity of 0.43 μA μM-1 cm-2. The proposed sensor showed good repeatability, reproducibility, and stability in LSV analysis. The fabricated MST sensor was successfully applied to the analysis of real samples (river water and corn) with good recovery results.
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Affiliation(s)
- Balamurugan Karuppaiah
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Zhongxiao East Road, Da'an District, Taipei City, Taiwan, ROC
| | - Anupriya Jeyaraman
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Zhongxiao East Road, Da'an District, Taipei City, Taiwan, ROC
| | - Shen-Ming Chen
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Section 3, Zhongxiao East Road, Da'an District, Taipei City, Taiwan, ROC.
| | - Prajakta R Chavan
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, Republic of Korea
| | - Raj Karthik
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, Republic of Korea.
| | - Mahmudul Hasan
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, Republic of Korea
| | - Jae-Jin Shim
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk, 38541, Republic of Korea
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Xu W, Xu Y, Schultz T, Lu Y, Koch N, Pinna N. Heterostructured and Mesoporous Nb 2O 5@TiO 2 Core-Shell Spheres as the Negative Electrode in Li-Ion Batteries. ACS APPLIED MATERIALS & INTERFACES 2023; 15:795-805. [PMID: 36542687 DOI: 10.1021/acsami.2c15124] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Niobium pentoxides have received considerable attention and are promising anode materials for lithium-ion batteries (LIBs), due to their fast Li storage kinetics and high capacity. However, their cycling stability and rate performance are still limited owing to their intrinsic insulating properties and structural degradation during charging and discharging. Herein, a series of mesoporous Nb2O5@TiO2 core-shell spherical heterostructures have been prepared for the first time by a sol-gel method and investigated as anode materials in LIBs. Mesoporosity can provide numerous open and short pathways for Li+ diffusion; meanwhile, heterostructures can simultaneously enhance the electronic conductivity and thus improve the rate capability. The TiO2 coating layer shows robust crystalline skeletons during repeated lithium insertion and extraction processes, retaining high structural integrity and, thereby, enhancing cycling stability. The electrochemical behavior is strongly dependent on the thickness of the TiO2 layer. After optimization, a mesoporous Nb2O5@TiO2 core-shell structure with a ∼13 nm thick TiO2 layer delivers a high specific capacity of 136 mA h g-1 at 5 A g-1 and exceptional cycling stability (88.3% retention over 1000 cycles at 0.5 A g-1). This work provides a facile strategy to obtain mesoporous Nb2O5@TiO2 core-shell spherical structures and underlines the importance of structural engineering for improving the performance of battery materials.
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Affiliation(s)
- Wenlei Xu
- Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Yaolin Xu
- Department of Electrochemical Energy Storage, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
| | - Thorsten Schultz
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
| | - Yan Lu
- Department of Electrochemical Energy Storage, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
- Institute of Chemistry, University of Potsdam, Potsdam 14476, Germany
| | - Norbert Koch
- Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
| | - Nicola Pinna
- Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
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Abebe E, Ujihara M. Influence of Temperature on ZnO/Co 3O 4 Nanocomposites for High Energy Storage Supercapacitors. ACS OMEGA 2021; 6:23750-23763. [PMID: 34568655 PMCID: PMC8459362 DOI: 10.1021/acsomega.1c02059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 08/06/2021] [Indexed: 06/13/2023]
Abstract
We developed a two-step chemical bath deposition method followed by calcination for the production of ZnO/Co3O4 nanocomposites. In aqueous reactions, ZnO nanotubes were first densely grown on Ni foam, and then flat nanosheets of Co3O4 developed and formed a porous film. The aspect ratio and conductivity of the Co3O4 nanosheets were improved by the existence of the ZnO nanotubes, while the bath deposition from a mixture of Zn/Co precursors (one-step method) resulted in a wrinkled plate of Zn/Co oxides. As a supercapacitor electrode, the ZnO/Co3O4 nanosheets formed by the two-step method exhibited a high capacitance, and after being calcined at 450 °C, these nanosheets attained the highest specific capacitance (940 F g-1) at a scan rate of 5 mV s-1 in the cyclic voltammetry analysis. This value was significantly higher than those of single-component electrodes, Co3O4 (785 F g-1) and ZnO (200 F g-1); therefore, the presence of a synergistic effect was suggested. From the charge/discharge curves, the specific capacitance of ZnO/Co3O4 calcined at 450 °C was calculated to be 740 F g-1 at a current density of 0.75 A g-1, and 85.7% of the initial capacitance was retained after 1000 cycles. A symmetrical configuration exhibited a good cycling stability (Coulombic efficiency of 99.6% over 1000 cycles) and satisfied both the energy density (36.6 Wh kg-1) and the power density (356 W kg-1). Thus, the ZnO/Co3O4 nanocomposite prepared by this simple two-step chemical bath deposition and subsequent calcination at 450 °C is a promising material for pseudocapacitors. Furthermore, this approach can be applied to other metal oxide nanocomposites with intricate structures to extend the design possibility of active materials for electrochemical devices.
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Kumar P, Chandra Mathpal M, Jagannath G, Prakash J, Maze JR, Roos WD, Swart HC. Optical limiting applications of resonating plasmonic Au nanoparticles in a dielectric glass medium. NANOTECHNOLOGY 2021; 32:345709. [PMID: 33962405 DOI: 10.1088/1361-6528/abfee6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/07/2021] [Indexed: 06/12/2023]
Abstract
Plasmonic nanostructures exhibiting high optical nonlinearities are widely used in the rapidly growing modern nanotechnology of nonlinear optics including biomedical applications due to their tunable plasmonic behavior. In this work, we investigate the nonlinear optical properties of uniformly distributed Au nanoparticles (NPs) embedded in pre-synthesized sodium-zinc borate glass by the well-known ion-exchange technique for optical limiting (OL) applications. Various techniques such as optical absorption spectroscopy, x-ray photoelectron spectroscopy, Transmission Electron Microscope (TEM), Photoluminescence, Time of Flight secondary mass spectroscopy and the Z scan technique were used for the characterization of these NPs. TEM confirmed spherically shaped Au NPs with varying sizes of up to 16 nm, in agreement with optical absorption spectroscopy. Nonlinear optical (NLO) properties of these Au NPs were investigated by using an open as well as close aperture Z scan technique which exhibited enhanced optical nonlinearities. The two-photon absorption (2PA) coefficients demonstrated an increasing trend while the OL threshold values demonstrated a decreasing trend as a function of heat treatment. The improved 2PA coefficients and decreased OL threshold values endorsed the Au NPs containing glasses as contending materials for the fabrication of promising optical limiters for the protection of eyes and other sensitive instruments from laser induced damages.
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Affiliation(s)
- Promod Kumar
- Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa
| | - Mohan Chandra Mathpal
- Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, Chile
| | - Gangareddy Jagannath
- Department of Physics, K S Institute of Technology, Bengaluru 560109, Karnataka, India
| | - Jai Prakash
- Department of Chemistry, National Institute of Technology Hamirpur, Hamirpur-177005 (H.P), India
| | - Jero-R Maze
- Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago, Chile
| | - W D Roos
- Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa
| | - H C Swart
- Department of Physics, University of the Free State, Bloemfontein, ZA9300, South Africa
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7
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Li Y, Liao C, Tjong SC. Recent Advances in Zinc Oxide Nanostructures with Antimicrobial Activities. Int J Mol Sci 2020; 21:E8836. [PMID: 33266476 PMCID: PMC7700383 DOI: 10.3390/ijms21228836] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/18/2022] Open
Abstract
This article reviews the recent developments in the synthesis, antibacterial activity, and visible-light photocatalytic bacterial inactivation of nano-zinc oxide. Polycrystalline wurtzite ZnO nanostructures with a hexagonal lattice having different shapes can be synthesized by means of vapor-, liquid-, and solid-phase processing techniques. Among these, ZnO hierarchical nanostructures prepared from the liquid phase route are commonly used for antimicrobial activity. In particular, plant extract-mediated biosynthesis is a single step process for preparing nano-ZnO without using surfactants and toxic chemicals. The phytochemical molecules of natural plant extracts are attractive agents for reducing and stabilizing zinc ions of zinc salt precursors to form green ZnO nanostructures. The peel extracts of certain citrus fruits like grapefruits, lemons and oranges, acting as excellent chelating agents for zinc ions. Furthermore, phytochemicals of the plant extracts capped on ZnO nanomaterials are very effective for killing various bacterial strains, leading to low minimum inhibitory concentration (MIC) values. Bioactive phytocompounds from green ZnO also inhibit hemolysis of Staphylococcus aureus infected red blood cells and inflammatory activity of mammalian immune system. In general, three mechanisms have been adopted to explain bactericidal activity of ZnO nanomaterials, including direct contact killing, reactive oxygen species (ROS) production, and released zinc ion inactivation. These toxic effects lead to the destruction of bacterial membrane, denaturation of enzyme, inhibition of cellular respiration and deoxyribonucleic acid replication, causing leakage of the cytoplasmic content and eventual cell death. Meanwhile, antimicrobial activity of doped and modified ZnO nanomaterials under visible light can be attributed to photogeneration of ROS on their surfaces. Thus particular attention is paid to the design and synthesis of visible light-activated ZnO photocatalysts with antibacterial properties.
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Affiliation(s)
- Yuchao Li
- Department of Materials Science and Engineering, Liaocheng University, Liaocheng 252000, China;
| | - Chengzhu Liao
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Sie Chin Tjong
- Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
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Branzi L, Back M, Cortelletti P, Pinna N, Benedetti A, Speghini A. Sodium niobate based hierarchical 3D perovskite nanoparticle clusters. Dalton Trans 2020; 49:15195-15203. [PMID: 33030177 DOI: 10.1039/d0dt02768e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report a microwave assisted synthesis of NaNbO3 perovskite mesocrystals with a hierarchical morphology formed by the self-assembly of nanoparticles in particle clusters. The synthesis method combines non-aqueous sol-gel synthesis and microwave heating in a single step process that allows us to isolate crystalline single phase NaNbO3 in few minutes. A detailed investigation of the effect of the reaction temperature on the crystallinity and morphology of the product was conducted. The synthesis stabilizes the unusual orthorhombic phase Pmma, a property that can be ascribed to the crystal size (24 nm). TEM and SAED analyses show that the hierarchical polycrystalline particles behave as single crystals, a feature related to a non-classical crystallization mechanism. Moreover, the optical bandgap of this NaNbO3 phase was estimated for the first time. The results suggest the potential of this synthetic procedure for the fast production of high quality tertiary oxide nanocrystals.
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Affiliation(s)
- Lorenzo Branzi
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy.
| | - Michele Back
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy.
| | - Paolo Cortelletti
- Nanomaterials Research Group, Department of Biotechnology and INSTM, RU Verona, University of Verona, Strada le Grazie 15, Verona, Italy.
| | - Nicola Pinna
- Institut für Chemie and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - Alvise Benedetti
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, Venezia Mestre, Italy.
| | - Adolfo Speghini
- Nanomaterials Research Group, Department of Biotechnology and INSTM, RU Verona, University of Verona, Strada le Grazie 15, Verona, Italy.
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Kumar P, Mathpal MC, Inwati GK, Ghosh S, Kumar V, Roos WD, Swart HC. Optical and surface properties of Zn doped CdO nanorods and antimicrobial applications. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125369] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Xu W, Russo PA, Schultz T, Koch N, Pinna N. Niobium‐Doped Titanium Dioxide with High Dopant Contents for Enhanced Lithium‐Ion Storage. ChemElectroChem 2020. [DOI: 10.1002/celc.202001040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Wenlei Xu
- Institut für Chemie and IRIS Adlershof Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Patrícia A. Russo
- Institut für Chemie and IRIS Adlershof Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Thorsten Schultz
- Institut für Physik and IRIS Adlershof Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein Str. 15 12489 Berlin Germany
| | - Norbert Koch
- Institut für Physik and IRIS Adlershof Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein Str. 15 12489 Berlin Germany
| | - Nicola Pinna
- Institut für Chemie and IRIS Adlershof Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
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Flores CLI, Balela MDL. Electrocatalytic oxygen evolution reaction of hierarchical micro/nanostructured mixed transition cobalt oxide in alkaline medium. J Solid State Electrochem 2020. [DOI: 10.1007/s10008-020-04530-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
Abstract
Niobium pentoxides are promising acid catalysts for the conversion of biomass into fuels and chemicals. Developing new synthesis routes is essential for designing niobium pentoxide catalysts with improved activity for specific practical processes. Here we show a synthesis approach in acetophenone, which produces nanostructured niobium pentoxides with varying structure and acidity that act as efficient acid catalysts. The oxides have orthorhombic structures with different extents of distortions and coordinatively unsaturated metal atoms. A strong dependence is observed between the type and strength of the acid sites and specific structural motifs. Ultrasmall niobium pentoxide nanoparticles, which have strong Brønsted acidity, as well as Lewis acidity, give product yields of 96% (3 h, 140 °C, 100% conversion), 85% (3 h, 140 °C, 86% conversion), and 100% (3 h, 110 °C, 100% conversion) in the reactions of furfuryl alcohol, 5-(hydroxymethyl)furfural, and α-angelica lactone with ethanol, respectively.
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Acedera RAE, Balela MDL. Hierarchical Urchin-like Spinel CuxCo3-xO4 Particles as Oxygen Evolution Reaction Catalysts in Alkaline Medium. ACTA ACUST UNITED AC 2019. [DOI: 10.1088/1757-899x/617/1/012004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Wang Z, Xiao X, Zou T, Yang Y, Xing X, Zhao R, Wang Z, Wang Y. Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 9:E32. [PMID: 30591648 PMCID: PMC6358774 DOI: 10.3390/nano9010032] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 12/20/2018] [Accepted: 12/20/2018] [Indexed: 12/23/2022]
Abstract
Citric acid capped CdS quantum dots (CA-CdS QDs), a new assembled fluorescent probe for copper ions (Cu2+), was synthesized successfully by a simple hydrothermal method. In this work, the fluorescence sensor for the detection of heavy and transition metal (HTM) ions has been extensively studied in aqueous solution. The results of the present study indicate that the obtained CA-CdS QDs could detect Cu2+ with high sensitivity and selectivity. It found that the existence of Cu2+ has a significant fluorescence quenching with a large red shifted (from greenish-yellow to yellowish-orange), but not in the presence of 17 other HTM ions. As a result, Cu₂S, the energy level below the CdS conduction band, could be formed at the surface of the CA-CdS QDs and leads to the quenching of fluorescence of CA-CdS QDs. Under optimal conditions, the copper ions detection range using the synthesized fluorescence sensor was 1.0 × 10‒8 M to 5.0 × 10‒5 M and the limit of detection (LOD) is 9.2 × 10‒9 M. Besides, the as-synthesized CA-CdS QDs sensor exhibited good selectivity toward Cu2+ relative to other common metal ions. Thus, the CA-CdS QDs has potential applications for detecting Cu2+ in real water samples.
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Affiliation(s)
- Zhezhe Wang
- School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
- Department of Physics, Yunnan University, Kunming 650091, China.
| | - Xuechun Xiao
- Department of Physics, Yunnan University, Kunming 650091, China.
| | - Tong Zou
- School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Yue Yang
- Department of Physics, Yunnan University, Kunming 650091, China.
| | - Xinxin Xing
- Department of Physics, Yunnan University, Kunming 650091, China.
| | - Rongjun Zhao
- School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
- Department of Physics, Yunnan University, Kunming 650091, China.
| | - Zidong Wang
- School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
| | - Yude Wang
- School of Materials Science and Engineering, Yunnan University, Kunming 650091, China.
- Key Lab of Quantum Information of Yunnan Province, Yunnan University, Kunming 650091, China.
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