JOURNAL OF MATERIALS SCIENCE
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2019
·Vol. 55
·期 4
·1475-1488
·
IF 3.442
Huo Hang,Jiang Yanqiu,Zhao Tingting,Wang Zhe,Hu Yanjing,Xu Xianzhu,Lin Kaifeng
Noble metal nanoparticles are widely applied in the catalytic reactions with projected superior activity and selectivity. Usually, the surface atomic species function as active sites, and tailoring the size of the nanoparticles can control the catalytic activity of metal nanoparticles. However, it is still of great challenge to synthesize ultra-small metallic nanoparticles owing to the Ostwald ripening. Herein, confinement of molecularly imprinted cavities strategy was utilized to quantitatively load ultra-small Ag nanoparticles in the mesoporous silica matrix. The average particle size of the Ag nanoparticles was calculated to be around 2 nm, and these nanoparticles were uniformly dispersed in the skeleton of silica matrix without blocking the mesopores. The contents of Ag nanoparticles can be accurately adjusted according to the incorporated organosilica in the mesoporous silica matrix. As expected, the supported Ag nanoparticles exhibited highly efficient catalytic performance towards 4-nitrophenol hydrogenation reactions and showed considerable recycling stability without loss of Ag species.
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高影响因子
WATER ENVIRONMENT RESEARCH
·
2019
·Vol. 92
·期 5
·713-721
·
IF 1.24
Yunhai Zhang,Shuangxi Zhou,Xin Su,Jimin Xu,Guangze Nie,Yongjun Zhang,Yide He,Shuili Yu
A p-type TiO 2 with Ti vacancies (D-TiO 2 ) was synthesized by a facile solvothermal treatment, and Ag/TiO 2 with different Ag loading amount was prepared through a photo-reduction deposition method. The samples were characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The adsorption and photocatalytic characteristics of tetrabromobisphenol A (TBBPA) on D-TiO 2 and Ag/TiO 2 were investigated. The adsorption of TBBPA on Ag/TiO 2 was significantly enhanced and was five times greater than that of pure TiO 2 . The increase in pH significantly inhibited the adsorption of TBBPA. The 2%-Ag/TiO 2 nearly completely degraded TBBPA in 10 min under UV–Vis light (λ > 360 nm), and the apparent reaction rate constant ( k app ) reached 0.63 min −1 . The significantly enhanced UV–Vis light catalytic properties of the Ag/TiO 2 in comparison with that of TiO 2 were attributed to the increased adsorption capacity and electron transfer ability of the Ag/TiO 2 . Free radical trap experiments results showed that holes and superoxide radicals play a major role in the catalytic degradation of TBBPA by Ag/TiO 2 . Moreover, the Ag/TiO 2 catalyst exhibits high stability during TBBPA degradation even after three cycles. Practitioner points Ti-defected TiO 2 and Ag/TiO 2 were synthesized using a solvothermal and photo-reduction deposition, respectively. Ag/TiO 2 exhibited outstanding adsorption and photocatalytic activity for TBBPA removal under UV–Vis light. Holes and superoxide radicals play a major role in the photocatalytic degradation of TBBPA.
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Environmental Science-Nano
·
2019
·Vol. 6
·期 4
·1168-1179
·
IF 7.704
Ziqiang Xu,Hang He,Shuyuan Zhang,Beibei Wang,Jiancheng Jin,Cao Li,Xueqin Chen,Bingbing Jiang,Yi Liu
In this work, carboxylated carbon dots (C-CDs) with higher oxidation degrees or hydroxylated CDs (H-CDs) with lower oxidation degrees were applied to fabricate CDs capped silver nanoparticles (denoted as C-CDs@AgNPs and H-CDs@AgNPs, respectively) via a one-step strategy. These two types of as-prepared AgNPs have similar size, morphology and surface charge. Interestingly, both AgNPs exhibit a higher toxicity against Gram-negative bacteria Escherichia coli (E. coli) than against Gram-positive bacteria Staphylococcus aureus (S. aureus), and the AgNPs decorated with H-CDs with lower oxidation degrees can eliminate both bacteria more effectively. Subsequently, the possible reason for this fascinating phenomenon has been explored clearly in the perspective of nano/cell interface interactions, which has rarely been considered in detail in previous work. The species specific antibacterial activity can be understood by the typical structural difference of the two bacteria, i.e. the presence of hydrophilic lipopolysaccharides (LPS) which facilitate the adsorption of AgNPs onto the surface of E. coli and the absence of hydrophilic LPS and the existence of thicker peptidoglycan (PG) on S. aureus which prevent the adsorption of AgNPs. Interestingly, the adsorption capacity of H-CDs@AgNPs towards E. coli is also much larger than that of C-CDs@AgNPs, while their different abilities to eliminate S. aureus can be interpreted by the faster leakage rate of Ag+ from the H-CDs@AgNPs. The above adsorption capacity has been quantified through the association constants between AgNPs and LPS or PG determined by UV-vis absorption spectroscopy. The above mechanism can also be illustrated by the microscopic analysis and permeability changes of the two bacteria induced by the AgNPs. Our results may provide valuable insights into optimization of other AgNPs for security and practical disinfection application.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xia Yang,Xin Qi,Guoqiang Ma,Zhaoyang Li,Qian Liu,Sara Khan,Yongjie Zhao,Leilei Zhang,Zhi Geng,Yingna Guo
Z -Scheme Ag/TiO 2 /AgMIL-101(Cr) was prepared by co-doping Ag and TiO 2 with AgMIL-101(Cr) via solvothermal synthesis combined with sol-gel method. Ag and anatase TiO 2 nanoparticles were well dispersed on the surface of AgMIL-101(Cr) with octahedral structure. 5 wt% Ag and 50% TiO 2 co-doping on the AgMIL-101(Cr) (Ag 5 T 50 Ag 5 M) exhibited large specific surface area (346.5 m 2 ·g −1 ) and narrow band gap 2.16 eV. Only 10 min of UV light irradiation resulted in the conversion of nitrate and nitrogen selectivity up to 100% over Ag 5 T 50 Ag 5 M. After 5 cycles of nitrate removal, the conversion of nitrate remained 90% indicating that catalyst had stable reusability. Moreover, instead of formic acid , ofloxacin (OFX) was used as a hole scavenger to evaluate the ability of Ag 5 T 50 Ag 5 M for the nitrate reduction. The result showed that the concentration of OFX was important factor to affect the conversion of nitrate. Based on the above discussion about the characterization and photocatalytic nitrate reduction, combined with the photoluminescence and electrochemical measurement results, the enhanced conversion of nitrate and nitrogen selectivity was reasonably explained. Finally, the route of electron transfer during the three constituents constructed Z -Scheme system and the mechanism of nitrate reduction to nitrogen was presumed.
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ANALYTICAL SCIENCES
·
2019
·Vol. 35
·期 7
·733-738
·
IF 1.618
Zhao Rui,Wang Yue,Zhang Zhiqiang,Hasebe Yasushi,Tao Dongping
Molybdenite (MLN) was physically co-adsorbed with Ag nanoparticles (Ag) on a glassy carbon electrode (GCE) for selectively sensing of ascorbic acid (AA). The composite was characterized with a scan electron microscope, a hightemperature confocal laser scanning microscope, an X-ray diffractometer, an X-ray fluorescence analyzer and electrochemical methods. The prepared MLN/Ag-GCE sensor exhibited good properties including a linear range from 3.0 × 10 −5 to 1.0 × 10 −3 M toward AA, a low detection limit of 1.5 × 10 −5 M, good selectivity, excellent reproducibility, and good stability. The synergistic effect between MLN and Ag nanoparticles results in an enhancement of the electrocatalytic activity for molybdenite.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2019
·
IF 2.931
Jian-Jun Li,Dan Qiao,Jing Zhao,Guo-Jun Weng,Jian Zhu,Jun-Wu Zhao
The applications of metallic nanoclusters and nanoparticles in biological sensing have attracted special attention owing to their optical interaction based on fluorescence and surface plasmon resonance (SPR). In this work, we designed a fluorescent nanoprobe for the determination of L -cysteine ( L -Cys) based on fluorescence resonance energy transfer (FRET) from gold‑silver bimetallic nanoclusters (Au-Ag NCs) to gold nanorods (AuNRs). Firstly, the negatively charged Au-Ag NCs protected by bovine serum albumin (BSA) are directly adsorbed on the surface of the positively charged AuNRs through electrostatic interaction , and the FRET effect leads to distinct fluorescence quenching of Au-Ag NCs at 615 nm. The SPR wavelength of AuNRs is dependent on the aspect ratio, so the SPR of AuNRs could be tuned to have a better spectral overlap with fluorescence of Au-Ag NCs, which enhances the fluorescence quenching effect. Because the SH group of L -Cys has an affinity with gold, the addition of L -Cys can result in the release of Au-Ag NCs from the surface of AuNRs via forming Au S bonds. Thus, the introduction of L -Cys could effectively restore the fluorescence emission of the AuNRs/Au-Ag NCs system because of the restraint of FRET effect. Under the optimized conditions, the fluorescence recovery of AuNRs/Au-Ag NCs probe exhibits a linear response to L -Cys concentration ranging from 5 to 100 μM, and the corresponding theoretical detection limit (LOD) is 1.73 μM. Meanwhile, this method displays excellent sensitivity and selectivity for L -Cys over other amino acids , and it has been successfully applied to detect L -Cys in real samples.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 16
·9761-9772
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IF 10.733
Chengyan Liu,Zhiwei Huang,Dianhui Wang,Xiuxia Wang,Lei Miao,Xiaoyang Wang,Shaohai Wu,Nozomu Toyama,Toru Asaka,Junliang Chen,Eiji Nishibori,Li-Dong Zhao
Recently, thermoelectric lead-free selenides have attracted great attention due to their earth-abundant, low-cost and environment-friendly characteristics. Here we report a new strategy to simultaneously enhance the electronic transport properties and reduce the thermal conductivity of polycrystalline SnSe2. By combining weak van der Waals bonding with the mobile behavior of Ag+ ions, the carrier concentration is optimized over a wide temperature range, which can be attributed to the dynamic Ag+-intercalation into the van der Waals gap from the Ag+ ion reservoir AgSnSe2. On account of additional electrical bridges between interlayers contributed by the intercalated Ag+ ions and weak anisotropy, an exciting high power factor of up to ∼7.46 μW cm−1 K−2 at 789 K is achieved along the pressing direction. In addition, the thermal conductivity is simultaneously reduced to ∼0.57 W m−1 K−1 at 789 K, owing to numerous line defects, phase interfaces, twin boundaries, dislocations and intercalated atomic layers generated after Ag introduction, as well as the anharmonic vibration of Ag+ ions. As a result, a record peak ZT of ∼1.03 at 789 K is realized along the pressing direction, which is ∼1.6 times larger than the highest reported value (0.63) of polycrystalline SnSe2 and even comparable to that of p-type polycrystalline SnSe. This study opens a new way to achieve ultra-high thermoelectric performance, especially in layered materials.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Chunyan Ma,De-Kun Ma,Wenyuan Yu,Wei Chen,Shaoming Huang
Photoelectrochemical (PEC) water splitting that can mimic natural photosynthesis to directly harvest and convert solar energy into clean and sustainable hydrogen energy, has been known as a promising avenue for addressing environmental pollution and energy crisis. Spinel-type CuBi 2 O 4 semiconductor as a promising photocathode material for solar water reduction has attracted much attention because of its many unique advantages. However, PEC activity of pristine CuBi 2 O 4 is far from satisfying because of its poor charge carrier transport and transfer efficiency. Herein we report that Ag + ions and N-doped graphene quantum dots (NGQDs) co-modified CuBi 2 O 4 submicron rods (NGQDs/Ag-CBO SMRs) photocathode can show enhanced PEC activity. Our work demonstrated that one-dimensional structure, Ag + ions doping, and NGQDs loading benefited the separation and transfer of photogenerated carriers and improved light harvesting ability, which were collectively contributed to enhanced PEC activity of NGQDs/Ag-CBO SMRs photocathode. As a result, the photocurrent density achieved on NGQDs/Ag-CBO SMRs photocathode under AM1.5G simulated sunlight at 0.3 V vs. RHE was 8.8, 2.3, 1.8, and 5.9-times larger than those obtained on CBO SMRs, Ag-CBO SMRs, NGQDs/CBO SMRs, and NGQDs/Ag-CBO microspheres (MSs) ones, respectively. The present study provides a new strategy for designing low-cost and highly efficient photocathodes.
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Advanced Materials Interfaces
·
2019
·Vol. 6
·期 16
·1900659
·
IF 4.713
Qingyun Liu,Ping Chen,Yongqin Ye,Ying Wan,Bin Wang,Zhiqiang Luo
Developing plasmon-assisted semiconductor nanocomposites as multifunctional surface-enhanced Raman scattering (SERS) substrate for detection as well as photodegradation of toxic organic pollutants appears to be a crucial step in upgrading the SERS technique to a quantitative analytical level. However, conventional photocatalytic semiconductor scaffolds are confined in ultraviolet-light-active metal oxide nanostructures (TiO 2 , ZnO, etc.). Herein, the scope of semiconductor scaffold is expanded to visible-light-active oxynitrides by developing a robust and ultrasensitive recyclable SERS substrate based on 3D hierarchical gallium oxynitrides (GaON) nanosheets loading with Ag nanoparticles (Ag NPs). Significantly, the bandgap of GaON nanosheets shrinks to 2.9 eV to enable visible-light adsorption. The as-fabricated SERS substrate shows a high sensitivity with enhancement factor of 5.2 × 10 7 in R6G detection, and yields a wide detection range of 1.0 × 10 −6 –1.0 × 10 −12 mol L −1 . Assisted with the enhanced charge transfer by generating the Schottky contact at the metal/semiconductor interface and the electron traps played by the residue oxygen, the Ag/GaON nanocomposites show attractive recyclability at visible-light irradiation with well-maintained SERS activity after four cycles. This work demonstrates the superiority of taking advantage of plasmon-assisted oxynitride semiconductors as a high-performance SERS platform and provides new opportunities for developing robust visible-light-driven recyclable SERS substrates.
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Journal of Materials Chemistry C
·
2019
·Vol. 7
·期 27
·8432-8441
·
IF 6.641
Jing Zhao,Chen Wu,Lipeng Zhai,Xiaofeng Shi,Xin Li,Guojun Weng,Jian Zhu,Jianjun Li,Jun-Wu Zhao
A surface-enhanced Raman scattering (SERS)-based sandwich type immunoassay was developed for the detection of α-fetoprotein (AFP) with high sensitivity, reproducibility and selectivity. In the immunoassay, an antibody immobilized nitrocellulose (NC) membrane was employed to capture AFP and antibody conjugated silica coated gold/silver core–shell nanostars (AuNS@Ag@SiO2) were used as SERS probes. AuNS@Ag was synthesized by the direct deposition of Ag on the AuNS. The Ag shell grew outward from the center towards the tips and adopted a polyhedral shape. The AuNS@Ag nanoparticles were shown to have higher SERS activity than gold nanostars (AuNSs), and their LSPR wavelengths could be finely tuned across a wide spectrum ranging from visible to near-infrared by simply adjusting the Ag shell thickness. The silica coating improved colloidal stability of the nanostructure and provided functionality for antibody conjugation. By using 4-mercaptobenzoic acid (4-MBA) as a Raman reporter molecule, the proposed SERS sensor is able to detect AFP with a low limit of detection (LOD) of 0.72 pg mL−1 and a wide and clinically relevant linear detection range from 3 pg mL−1 to 3 μg mL−1. Hence, this SERS-based immunoassay provides a strategy for the detection of trace AFP and has potential to assist in the monitoring of prognosis for hepatocellular carcinoma (HCC) patients.
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CRYSTENGCOMM
·
2019
·Vol. 21
·期 24
·3709-3720
·
IF 3.382
Shanshan Li,Qi Wang,Xinyu Song,Yuxiang Bu
Semiconductor-based materials as SERS-active substrates have gained significant attention because of their superior properties. However, to date, only few studies have been reported on the SERS performance of substrates fabricated using CdS-based composites. In this study, hollow sphere-like Ag/CdS nanocomposites (NCs) with multi-hot spots were successfully synthesized via a room-temperature solution route without the addition of surfactant. Especially, note that in our strategy, the cadmium ions in an aqueous solution originating from the self-template core dissolved with acid were retrieved and recycled via a simple approach, avoiding the wastage of resources and environmental problems. Moreover, a strong electromagnetic enhancement between two neighboring Ag nanoparticles (NPs) on the CdS sphere-like surface could be achieved by conveniently adjusting the amount of the AgNO3 reagent. Note that the as-prepared substrate with low loading of Ag presented superior SERS performance with the ultralow limit of detection of 10−12 mol L−1 for R6G and CV, much higher than that of many recently reported composite substrates. These significantly enhanced SERS effects are attributed to the combination of several contributions, including plasmonic coupling between Ag NPs, synergistic charge-transfer resonances in the Ag/CdS/dye molecule system, and cadmium defect-induced electrostatic forces. As a consequence, the present study not only develops a convenient, environmentally friendly approach for the fabrication of noble/CdS composites but also indicates the promising potential application of these composites as ideal SERS substrates in the detection of organic pollutants.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2019
·Vol. 33
·期 5
·e4865
·
IF 3.259
Chao Duan,Chaoran Liu,Xin Meng,Wanli Lu,Yonghao Ni
In this work, we prepared high-performance and recyclable nanocatalysts that consist of small and well-dispersed silver nanoparticles (Ag NPs) immobilized onto Cu- based metal–organic framework (MOF-199 s) supported by carboxymethylated cellulose fibers (CCFs). The as-prepared green nanohybrid catalysts, namely Ag NPs@ MOF-199 s/CCFs, were characterized using SEM, TEM, XRD and FT-IR techniques. The catalytic performances showed that Ag NPs@ MOF-199 s/CCFs catalysts exhibited a very high catalytic efficiency towards the reduction of 4-nitrophenol to 4-aminophenol. The enhanced catalytic performances are attributed to the improved dispersity, small particles of Ag NPs stabilized by the MOF-199 s, and the porous catalyst structures. The introduction of cellulose fiber further facilitates the reuse and sustainability of the nanohybrid catalysts, showing a stable and high reusability (more than 91% of catalytic activity) even after five runs.
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