ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 27
·期 7
·7025-7039
·
IF 2.914
Gao Boru,Wang Jin,Dou Mengmeng,Xu Ce,Huang Xue
In present study, an efficient ternary Ag/TiO 2 /mesoporous g-C 3 N 4 (M-g-C 3 N 4 ) photocatalyst was successfully synthesized through depositing Ag nanoparticles (NPs) on the surface of TiO 2 /M-g-C 3 N 4 heterojunction. Ag/TiO 2 /M-g-C 3 N 4 nanocomposite displayed the highest degradation efficiency for amoxicillin (AMX) compared to TiO 2 /M-g-C 3 N 4 heterojunction, M-g-C 3 N 4 , and bulk-g-C 3 N 4 (B-g-C 3 N 4 ). The removal efficiency of AMX in real situation, surface water (SW), hospital wastewater (HW), and waste water treatment plant (WWTP) also were studied to illustrate the effectiveness of Ag/TiO 2 /M-g-C 3 N 4 photocatalysts. The vulnerable atoms in AMX structure were revealed through DFT calculation. Additionally, the dominating active groups produced in time of the photocatalytic procedure were determined on account of free radical trapping experiments and ESR spectra. The mechanism of photocatalytic degradation was proposed and verified. The transfer of the electrons and the inhibition of the recombination of photogenerated electron-holes were enhanced effectively under the synergistic effect of the Ag NPs and TiO 2 . As a consequence, the catalytic activity of the composite was improved under visible light.
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LANGMUIR
·
2020
·
IF 3.557
Yongfei Cui,Huanhuan Sun,Guodong Shen,Panpan Jing,Yongping Pu
Cocatalyst surface-loading has been regarded as an effective strategy to promote solar-energy-conversion efficiency. However, the potential influence of surface modification with cocatalysts on the photodegradation pathway and the underlying mechanisms is still unclear. Herein, we have used ferroelectric BaTiO3 as the substrate, and both the reduction cocatalyst Ag and the oxidation cocatalyst MnOx have been successfully loaded onto BaTiO3 simultaneously by a one-step photodeposition method as evidenced by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The influence of dual-cocatalyst surface-loading on photodegradation of rhodamine B has been systematically investigated for the first time. First, the dual-cocatalyst-modified BaTiO3 outperformed over the single-cocatalyst-loaded BaTiO3, and the photodegradation rate of Ag/BaTiO3/MnOx is about 3 times and 12 times as high as that of Ag/BaTiO3 and BaTiO3/MnOx, respectively. The credit is given to the synergistic effect between the reduction and oxidation cocatalysts, prompting charge carrier separation and migration as verified by the transient photocurrent, electrochemical impedance, and photoluminescence (PL) spectrum investigation. Second, in addition to the boosted photodegradation activity, the photodegradation pathway is found to be altered as well when using Ag/BaTiO3/MnOx. High-performance liquid chromatography (HPLC) analysis indicated that a highly selective stepwise deethylation process predominates over chromophore cleavage in the Ag/BaTiO3/MnOx system, while it is reverse for the Ag/BaTiO3 system. This phenomenon is attributed to the different dye molecule adsorption modes. Furthermore, the radical trapping experiment shows that holes play a major role in the degradation process, and the recycle test proves the excellent stability of Ag/BaTiO3/MnOx. Our findings may add another layer of understanding depth to cocatalyst surface modification in photodegradation applications.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2019
·Vol. 21
·期 11
·1-8
·
IF 2.009
Cao Sheng,Dai Chencheng,Zhao Jialong,Zou Bingsuo
In this work, a facile approach to synthesize the Ag- and Mn-codoped Zn-In-S nanocrystals (NCs) with dual emissions as ratiometric temperature sensors is reported. The as-synthesized codoped Zn-In-S NCs have a uniform size distribution and exhibit a zinc blende ZnS phase structure. Moreover, the as-produced codoped NCs show dual emission peaks which center at green and orange-red regions and have a photoluminescence quantum yield (PL QY) up to 45%. The time-resolved PL spectroscopy and X-ray photoelectron spectroscopy characterizations reveal that the dual emissions of these NCs are derived from the intrinsic emission of Ag + and Mn 2+ , respectively. Moreover, the relative intensity ratio of dual emissions can be tailored by adjusting the Ag and Mn doping concentrations. The as-built ratiometric temperature sensors based on the codoped NCs exhibit a thermometric sensitivity of ~ 0.17% K -1 over a broad window of 80–200 K, suggesting that these codoped Zn-In-S NCs are promisingly used for bio-optical ratiometric temperature sensing.
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Applied Nanoscience
·
2020
·Vol. 10
·期 6
·1845-1851
·
IF 2.88
Wang Tianxiong,Jiang Tiancai,Meng Xianquan
We found that the morphology of nanowires could be regulated by adding polyvinylpyrrolidone (PVP, K30) in hydrothermal synthesis of antimony sulfide (Sb 2 S 3 ) nanowires. The nanowires with length more than 20 μm were obtained by adding the proper amount of PVP. Three kinds of fully nanostructured photodetector using Sb 2 S 3 nanowires as active regions were fabricated and the first detector used silver nanowires as the electrodes at both ends, the second used silver nanowires as one electrode and MXenes as the another electrode, and the third used MXenes as both electrodes. The light response speed of the photodetector with both MXenes electrodes was improved greatly. The photodetector which used MXenes and silver nanowires as electrodes at two ends, respectively, showed the phenomenon of being self-driven. The mechanism of asymmetric hole migration was put forward to explain the effect of being self-driven.
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ANALYST
·
2019
·Vol. 145
·期 5
·1801-1809
·
IF 4.019
Kaiqiang Wang,Da-Wen Sun,Hongbin Pu,Qingyi Wei
In this study, a 4-aminobenzenethiol-functionalized core–shell silver-coated gold nanoparticle (Au@Ag-4ABT NP) system was designed for the rapid sensing of carbendazim (CBZ) using a combination of naked-eye colorimetry and surface-enhanced Raman spectroscopy (SERS) dual-channel approach. Under alkaline conditions, the deprotonated CBZ species could interact with Ag surfaces via the N–Ag–O and N–Ag–N bonds. As a result, the neighboring Au@Ag-4ABT NPs would come closer through π–π interactions inducing the aggregation of Au@Ag-4ABT NPs. The aggregation of nanoparticles caused changes in the optical properties of the colloidal system, allowing observation with naked eyes, while the generation of more localized surface plasmon resonance “hotspots” between the adjacent Au@Ag nanoparticles permitted monitoring by the SERS technique. The proposed method showed effective sensitivity toward CBZ with limit of detection and limit of quantitation values of 37 and 122 ppb, respectively. In addition, the proposed dual-channel assay could serve as a simple and rapid method for sensing CBZ in tap water, cauliflower, and pear juice within 30 min.
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MICROCHIMICA ACTA
·
2019
·Vol. 187
·期 1
·1-10
·
IF 5.479
Li Yue,Wang Yan,Wang Mingchao,Zhang Jinyue,Wang Qingwei,Li Hongji
In a new method for the determination of trace levels of chlorophenols in river waters, detection via surface-enhanced Raman scattering (SERS) is combined with recognition by a molecularly imprinted polymer (MIP). Nanoparticles of type Cu 2 O@Ag were synthesized by attaching silver particles to the surface of Cu 2 O nanoparticles. The Cu 2 O@Ag were then coated with a layer of a MIP that was obtained by atom transfer radical polymerization using from methacrylic acid as monomers and 2,6-dichlorophenol as the template. The morphology of Cu 2 O is found to be flower-like. The Cu 2 O@Ag-MIPs displays a strong SERS effect. Following removal of the template by rinsing with the mixture solution of methanol/acetic acid (9/1, v /v), the material was used to selectively bind 2,6-dichlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenol. The SERS peak intensity at 1580 cm −1 increases linearly with the concentration of the various chlorophenols in the range from 10 nM to 1 mM, and the detection limit is 5.8 nM. The imprinting factor is 4.62. The method was applied to the analysis of (spiked) river water, with recoveries ranging from 91.8 to 115.4% and relative standard deviations of <4.5%.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 31
·期 2
·1461-1471
·
IF 2.195
Zhou Bo,Cui Chunting,Ma Shenghua,Bai Jintao,Wang Hui
A novel Ag-doped glass frit is prepared by the sol-gel method. Nitrogen adsorption-desorption isotherms indicate that the frit has a large BET surface area and a small particle size which promotes front contact metallization. When the glass frit is used for the front contact electrode of polycrystalline silicon solar cells (pc-Si solar cells), it exhibits excellent wettability and etching results on the SiN x layer and the Si substrate. The pc-Si solar cells with the as-prepared frit has a better photoelectric conversion efficiency (18.2%) and is 0.8% higher than the solar cells using the conventional frit, which is due to the frit will produce a lot of Ag nanocrystals at the interface of the glass layer, promoting the formation of excellent ohmic contact between the Ag electrode and n-Si layer, and reducing the contact resistance of solar cells.
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ANALYTICAL CHEMISTRY
·
2019
·
IF 6.35
Xu Dong,Lukas Ohnoutek,Yang Yang,Yiqing Feng,Tao Wang,Muhammad Ali Tahir,Ventsislav K. Valev,Liwu Zhang
Surface enhanced Raman spectroscopy (SERS) shows great promise in studying individual atmospheric aerosol. However, the lack of efficient, stable, uniform, large-array, and low-cost SERS substrates constitutes a major roadblock. Herein, a new SERS substrate is proposed for detecting individual atmospheric aerosol particles. It is based on the sphere segment void (SSV) structure of copper and silver (Cu/Ag) alloy. The SSV structure is prepared by an electrodeposition method and presents a uniform distribution, over large 2 cm2 arrays and at low cost. The substrate offers a high SERS enhancement factor (due to Ag) combined with lasting stability (due to Cu). The SSV structure of the arrays generates a high density of SERS hotspots (1.3 × 1014/cm2), making it an excellent substrate for atmospheric aerosol detection. For stimulated sulfate aerosols, the Raman signal is greatly enhanced (>50 times), an order of magnitude more than previously reported substrates for the same purpose. For ambient particles, collected and studied on a heavy haze day, the enhanced Raman signal allows ready observation of morphology and identification of chemical components, such as nitrates and sulfates. This work provides an efficient strategy for developing SERS substrate for detecting individual atmospheric aerosol.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2022
·
IF 6.76
Jianzhi Wang,Yu Luo,Tong Xu,Ziyi Guo,Guopeng Chen,Yuchen Ren,Yanan Xue,Ning Cai,Hui Li,Faquan Yu
The development of low-cost and highly efficient electrocatalysts for oxygen evolution reaction (OER) with good conductivity, high specific surface area and abundant oxygen vacancies is of great significance for the future renewable energy conversion and storage system. Herein, Ag doped NiMoO 4 materials on the Ni foam (NiMoO 4 /Ag/NF) with rich oxygen vacancies were successfully prepared by hydrothermal strategy and layer by layer assembly method. The Ag ions are doped in-situ to promote electron transfer and compensate for the poor conductivity of metal oxides. The suitable air annealing treatment is used to create rich oxygen vacancies. The high specific surface area and one-dimensional characteristics of the cross mesoporous nanorod skeleton are responsible for the increased exposure of active centers and the rapid charge transfer behavior. The NiMoO 4 /Ag/NF exhibits high activity for OER in alkaline solution (an overpotential of 275 mV at the current density of 20 mA cm −2 ) and low Tafel slope (53.67 mV dec −1 ), and a satisfying durability in 1.0 M KOH. This study provides an effective method for the preparation of Ag doped one-dimensional nanomaterials with excellent OER catalytic performance and electrochemical stability.
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Science Bulletin
·
2016
·
IF 0
Lidan Xu,Min Hong,Yongliang Wang,Ming Li,Haibo Li,Madhavan P.N. Nair,Chen-Zhong Li
In this work, we demonstrated a simple and efficacious two-step method for the synthesis of Ag@Au core–shell nanoparticles (Ag@AuNPs) and the Ag/Au hollow nanocages (Ag/AuNCs) with Ag nanoparticles (AgNPs) as seeds by adjusting pH, and the preparation of hybrid Ag@AuNPs- or Ag/AuNCs-graphene oxide nanocomposites (Ag@AuNPs-GO or Ag/AuNCs-GO) based on the self-assembly. It was noticed from the electrostatic assembly experiment that the loading amount of Ag/AuNCs on GO nanosheet was more than that of Ag@AuNPs. The as-synthesized hybrid materials were characterized by transmission electron microscopy , atomic force microscopy , ζ-potential, high-angle annular dark-field scanning transmission electron microscopy, thermogravimetric analyzer and X-ray diffraction. Catalytic activities of Ag@AuNPs, Ag/AuNCs and Ag/AuNCs-GO nanostructures were investigated in the reduction of 4-, 3- or 2-nitrophenol to 4-, 3- or 2-aminophenol, and on the basis of comparative kinetic studies the following trend was obtained for the related catalytic activity: Ag/AuNCs-GO > Ag/AuNCs > Ag@AuNPs. These observations were attributed to the simultaneous effects of surface area available for catalytic reaction and composition of the hybrid nanostructures.
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RSC Advances
·
2022
·Vol. 12
·期 8
·4836-4842
·
IF 4.036
Yingxin Chen,Chunli Yang,Xiaotong Huang,Lu Li,Na Yu,Huan Xie,Zebin Zhu,Yong Yuan,Lihua Zhou
A composite of cuttlefish ink-based carbon quantum dots@Ag/MXene (CQD@Ag/MXene) was firstly synthesized by solvothermal method as a catalyst for reduction of p-nitrophenol (PNP) to p-aminophenol (PAP). CQD@Ag/MXene was characterized by scanning electron microscopy (SEM), field emission transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman. The results show that loading on 2D material MXene can prevent the aggregation of CQD@Ag and expose more active sites, which contributes to a superior catalytic activity with a pseudo-first-order rate constant k (2.28 × 10−2 s−1) and mass-normalized rate constant km (5700 s−1 g−1), nearly 2 times higher than CQD@Ag without MXene (k = 1.09 × 10−2 s−1 and km = 2725 s−1 g−1). Besides, CQD@Ag/MXene showed excellent reusability which even retained about 65% activity in successive 10 cycles. The high adsorption rate to PNP and the promotion of forming H radicals may be the reason for the outstanding catalytic activity of CQD@Ag/MXene. CQD@Ag/MXene can be a potential candidate in the removal of environmental pollutants due to its facile synthesis and high catalytic efficiency.
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Nanomaterials
·
2022
·Vol. 12
·期 14
·2394
·
IF 5.719
Xingang Chen,Lei Zhu,Zhipeng Ma,Meilin Wang,Rui Zhao,Yueyue Zou,Yijie Fan
Industrial wastewater containing large amounts of organic pollutants is a severe threat to the environment and human health. Thus, the rapid detection and removal of these pollutants from wastewater are essential to protect public health and the ecological environment. In this study, a multifunctional and reusable surface-enhanced Raman scattering (SERS) substrate by growing Ag nanoparticles (NPs) on ZnO nanorods (NRs) was produced for detecting and degrading Rhodamine B (RhB) dye. The ZnO/Ag substrate exhibited excellent sensitivity, and the limit of detection (LOD) for RhB was as low as 10−11M. Furthermore, the SERS substrate could efficiently degrade RhB, with a degradation efficiency of nearly 100% within 150 min. Moreover, it retained good SERS activity after multiple repeated uses. The interaction between Ag NPs, ZnO, and RhB was further investigated, and the mechanism of SERS and photocatalysis was proposed. The as-prepared ZnO/Ag composite structure could be highly applicable as a multifunctional SERS substrate for the rapid detection and photocatalytic degradation of trace amounts of organic pollutants in water.Keywords:SERS;organic pollutants;ZnO/Ag;sensitivity;photocatalytic
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