Plasmonics
·
2021
·Vol. 17
·期 2
·597-612
·
IF 2.404
Li Jian-Jun,Qin Qiu-Xiang,Weng Guo-Jun,Zhu Jian,Zhao Jun-Wu
In this study, Au–Ag nanoboxes are converted into Au–Ag alloy nanocages by increasing the hole size. The extinction spectrum and the refractive index sensing characteristics of Au–Ag alloy nanocages with different geometric parameters are studied by using discrete dipole approximation method (DDA). With the increase of Au composition, the peak of local surface plasmon resonance (LSPR) shows approximately linear redshift and the sensitivity factor shows approximately linear decrease. The refractive index sensitivity can be effectively controlled by the Au–Ag ratio at large hole size because the hole and cavity surfaces distribute more environmental dielectric components. Therefore, increasing the hole size and decreasing the Au–Ag ratio can improve the refractive index sensitivity. These calculation results have also been verified experimentally. In order to illustrate the influence of alloy composition on the LSPR characteristics and the refractive index sensitivity, the local electric field distributions under different geometric parameters are plotted. We find that the electric field direction on the hole and cavity surfaces is controlled by the Au–Ag ratio and environmental dielectric constant. Moreover, the field vectors on the hole and cavity surfaces are formed by the superposition of the incident field, the electric field generated by the oscillating electrons on the outer surface, and the polarized field in the environmental dielectric constant.
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FOOD CHEMISTRY
·
2021
·
IF 7.514
Zhihui Wu,Da-Wen Sun,Hongbin Pu,Qingyi Wei,Xuanran Lin
Mycotoxin B1 (AFB1) contamination in agricultural products pose a deadly danger to animal and human health and its rapid and reliable detection is thus very important. Herein, a ratiometric surface-enhanced Raman scattering (SERS) aptasensor for AFB1 detection was developed, in which 1,2-bis(4-pyridyl) ethylene (BPE) was used to trigger the assembly of Au nanoparticle dimers (AuNP dimers) and form intensive SERS “hot spots”, and MXenes nanosheets could load aptamer-modified AuNP dimers due to the hydrogen bonding and the chelation between the phosphate groups of aptamers and the Ti ion of MXenes. With the presence of AFB1 preferentially binding to AFB1 aptamer, AuNP dimers were separated from MXenes nanosheets, leading to a decrease in SERS intensity. Regression analysis in the range from 0.001 to 100 ng·mL −1 showed the limit of detection (LOD) being 0.6 pg·mL −1 in standard solution, indicating that the great prospects of the AuNP dimers/MXenes SERS substrate for detecting AFB1.
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Green Energy & Environment
·
2021
·
IF 8.207
Weiyao Yang,Mengchen Fu,Chenyu Yang,Yiwen Zhang,Chun Shen
Despite wide applications of noble metal-based catalysts in 5-hydroxymethylfurfural (HMF) oxidation, promoting the catalytic performance at low loading amounts still remains a significant challenge. Herein, a series of metal oxide modified MO x -Au/TiO 2 (M = Fe, Co, Ni) catalysts with low Au loading amount of 0.5 wt% were synthesized. Addition of transition metal oxides promotes electron transfer and generation of the Au δ − –O v –Ti 3+ interface. A combination study reveals that the dual-active site (Au δ − -O v -Ti 3+ ) governs the catalytic performance of the rate-determining step, namely hydroxyl group oxidation. Au δ − site facilitates chemisorption and activation of O 2 molecules. At the same time, O v -Ti 3+ site acts as the role of “killing two birds with one stone”: enhancing adsorption of both reactants, accelerating the activation and dissociation of H 2 O, and facilitating activation of the adsorbed O 2 . Besides, superoxide radicals instead of base is the active oxygen species during the rate-determining step. On this basis, a FDCA yield of 71.2% was achieved under base-free conditions, complying with the “green chemistry” principle. This work provides a new strategy for the transition metal oxides modification of Au-based catalysts, which would be constructive for the rational design of other heterogeneous catalysts.
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LANGMUIR
·
2021
·
IF 3.882
Mengjiao Yi,Lin Ma,Wenrong Zhao,Jie Zhao,Qi Fan,Jingcheng Hao
Cationic magnetic Gemini surfactants (mag-G-surfs), [C14H29(CH3)2N(CH2)2N(CH3)2C14H29]2+·2[XCl3Br]− (14-2-14·2X, X = Ce, Gd, or Ho), efficiently induce the aggregation of glutathione-protected Au nanoclusters (NCs) (GSH-Au NCs). These magnetic luminescent aggregates not only possess aggregation-induced emission (AIE) behavior but also display aggregation-induced magnetic enhancement. In particular, 14-2-14·2Ce and 14-2-14·2Gd have a better effect on boosting the luminescence intensity, quantum yield (QY), and luminescence lifetime (τ). The luminescent aggregates of GSH-Au NCs triggered by 14-2-14·2Gd or 14-2-14·2Ho exhibit more favorable paramagnetic behavior. Other Au NCs containing a Au(I)–thiolate complex shell also exhibit the obvious AIE phenomenon after introducing 14-2-14·2Gd, demonstrating the luminescence enhancement effect of mag-G-surfs. The luminescent aggregate 14-2-14·2Ce@GSH-Au NCs can serve as a “light up” fluorometric probe to detect cysteine selectively with the detection limit (DL) of 36 μM, and the magnetic luminescent aggregate 14-2-14·2Gd@GSH-Au NCs has the potential to be a novel contrast agent in T1-weighted magnetic resonance (MR) imaging due to its satisfactory contrasting ability.
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NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 12
·5551-5560
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IF 3.591
Xiangrong Huang,Zhuoyao Ni,Haiping Su,Yazhuo Shang,Honglai Liu,Yifan He,Hong Meng,Yinmao Dong
Precise and early detection of carcinoembryonic antigen (CEA) as a tumor marker of various cancers provides the best hope for the treatment of the deadly malignancy. Thus, the design of an immunosensor with high sensitivity is significant for early and accurate detection of CEA. In this work, a novel label-free electrochemical immunosensor was designed for the detection of CEA based on a nanostructured conductive polymer hydrogel loaded with gold nanoparticles (AuNPs). The hydrogel (BSNa-CNC-PPy) was simply prepared via in situ synthesis of polypyrrole (PPy) using cellulose nanocrystalline (CNC) and sodium benzenesulfonate (BSNa) as dopants to participate in the formation of the three-dimensional nano-hydrogel. AuNPs were further electrodeposited on the surface of BSNa-CNC-PPy gel-modified glassy carbon electrode (GCE). The immunoassay platform was obtained when the AuNPs/BSNa-CNC-PPy gel/GCE was incubated with anti-CEA and blocked by bovine serum albumin in succession. By combining the advantages of biocompatibility, nanostructure, outstanding hydrophilicity, excellent film-forming ability as well as the gelatinization of CNC, the CNC-PPy gel/GCE showed high conductivity (electroactive surface area), strong hydrophilicity, and film-forming property. The introduction of BSNa improved the conductivity of BSNa-CNC-PPy gel/GCE further due to enhanced interchain charge transport of PPy chains. The BSNa-CNC-PPy gel/GCE showed a 214% increase in electroactive surface area and the dried BSNa-CNC-PPy gel demonstrated a large specific surface area (76.59 m2 g−1), which were superior to those of existing conducting polymer hydrogels. AuNPs were apt to immobilize a mass of antibodies and accelerate electron transfer. The fabricated CEA-detecting immunosensor displayed a wide linear detection range of 1 fg mL−1 to 200 ng mL−1 and an ultralow limit of detection of 0.06 fg mL−1 (at a signal to noise ratio of 3). In addition to high sensitivity, the immunosensor exhibited excellent stability, high selectivity, good reproducibility, and strong reliability for real sample analysis. The proposed label-free electrochemical immunosensor has potential to be a diagnostic tool in clinical analysis of CEA.
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RSC Advances
·
2021
·Vol. 11
·期 24
·14678-14685
·
IF 3.361
Yiling Li,Shuxiao Yi,Zhongli Lei,Yan Xiao
It is of vital importance to develop probes to monitor hypochlorous acid (HClO) in biological systems as HClO is associated with many important physiological and pathological processes. Metal nanoclusters (NCs) are promising luminescent nanomaterials for highly reactive oxygen species (hROS) detection on the basis of their strong reaction ability with hROS. However, metal NCs typically can respond to most common hROS and are susceptible to etching by biothiols, hindering their application in the construction of effective HClO probes. Herein, we proposed a strategy to develop a nanoprobe based on Au NCs for highly sensitive and selective detection of HClO. We synthesized luminescent benzyl mercaptan-stabilized Au NCs and encapsulated them with an amphiphilic polymer (DSPE-PEG). After encapsulation, an obvious emission enhancement and good resistance to the etching by biothiols for Au NCs were achieved. More importantly, the DSPE-PEG encapsulated Au NCs can be used as a nanoprobe for detection of HClO with good performance. The luminescence of the Au NCs was effectively and selectively quenched by HClO. A good linear relationship with the concentration of HClO in the range of 5–35 μM and a limit of detection (LOD) of 1.4 μM were obtained. Additionally, this nanoprobe was successfully used for bioimaging and monitoring of HClO changes in live cells, suggesting the application potential of the as-prepared amphiphilic polymer-encapsulated Au NCs for further HClO-related biomedical research.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Hongye Yan,Lei Jiao,Hengjia Wang,Yuanmin Zhu,Yifeng Chen,Ling Shuai,Meng Gu,Ming Qiu,Wenling Gu,Chengzhou Zhu
The complex structure of nanomaterial causes great difficulty in identifying active sites of nanozymes and getting to the bottom of the catalytic mechanism. In this report, single-atom Bi-anchored Au (BiSA@Au) hydrogels were synthesized through a one-step reduction strategy, which enables the precise regulation of the nanozyme activity and specificity at the atomic scale and the in-depth understanding of their catalytic nature. Due to the single-atom Bi doping, the BiSA@Au hydrogels showed previously unachieved peroxidase (POD)-like activity, while the doped single Bi atoms had negligible effects on the enhancements of the other closely related redox enzyme-like activities. Density functional theory verified that the introduction of single Bi atoms not only enhances the adsorption of H 2 O 2 but also decreases the potential barriers for *OOH generation, leading to the boosted POD-like activity. Taking advantage of the unique porous nanowire networks of BiSA@Au hydrogels, a nanozyme/natural enzyme hybrid cascade reaction system was fabricated to achieve the sensitive colorimetric biosensor for glucose. This work paved a new route to rationally design functional nanozymes at the atomic scale, achieving the significant enhancement of POD-like activity with exceptional specificity.
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Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 22
·13080-13086
·
IF 12.732
Mei Zhang,You Xu,Shengqi Wang,Mengying Liu,Lianbang Wang,Ziqiang Wang,Xiaonian Li,Liang Wang,Hongjing Wang
How to boost the electrocatalytic performance of non-Pt catalysts for the hydrogen evolution reaction (HER) to substitute Pt is an important research topic. Herein, by combining a one-pot wet-chemical method and the post surface functionalization, we successfully fabricated polyethylenimine (PEI)-modified bimetallic Au@Rh core–shell mesoporous nanospheres (Au@Rh@PEI MNs). Benefiting from the synergetic effects of Au@Rh core–shell mesoporous architectures and interfacial modification by PEI molecules, the resultant Au@Rh@PEI MNs exhibit excellent electrocatalytic activity and stability for the HER in all pH value solutions, which even surpass the benchmark commercial Pt/C catalyst. Our synthetic protocol may offer guidelines for the rational design of advanced catalysts for water splitting and other electrocatalytic applications.
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ACS Applied Nano Materials
·
2021
·
IF 5.097
Lin Guo,Zhu Mao,Chao Ma,Jiawei Wu,Lin Zhu,Bing Zhao,Young Mee Jung
Nanoscale materials have an irreplaceable advantage in solar energy utilization because of their perfect match with visible light wavelength on the length scale. Charge transfer (CT) between a metal nanoparticle and contacted nanoscale semiconductor plays a significant role in photoinduced energy transfer. Here, we fabricated a new complex, a gold nanorod-4-mercaptobenzoic acid@Cu2O (Au NR-MBA@Cu2O) core–shell nanostructure, and used surface-enhanced Raman scattering (SERS) spectroscopy of the interlayer MBA molecules to investigate the CT process occurring between the Au NRs and Cu2O. In our system, different surface plasmon absorption bands were adjusted by tuning the thicknesses of the Cu2O shells on the Au NR core to explore the influence of plasmon absorption at different incident Raman laser lines. By analyzing the SERS spectra, the degree of CT was calculated, and the consequences can be fully explained by photoexcitation across interface electron transfer and plasmon-induced interfacial charge transfer transition at laser excitation wavelengths of 633 and 785 nm. This experiment introduced a simple, effective, and intuitive approach to observe the CT process in metal semiconductors by SERS. The results of our study will improve in photocatalytic efficiency and photoelectric devices.
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COLLOIDS AND SURFACES B-BIOINTERFACES
·
2020
·
IF 4.389
Hao Gan,Wenzhao Han,Zhendong Fu,Liping Wang
The nanocomposites with highly synergistic effect show important potential application as nanozymes. Herein, the chain-like Au/carbon dots (CDs) (GCDs) nanocomposites were prepared by self-assembly method. The negatively charged Au nanoparticles (NPs) and positively charged CDs were connected by the electrostatic interaction. Then, the electron transfer between Au and CDs induces the strong catalytic effect of GCDs nanocomposites. The cross-linking reaction occurred between amino groups and carboxyl groups on the surface of CDs, which led to form the chain-like Au aggregation surrounded by carbon shells. By FDTD simulation, the aggregation of Au NPs may enhance the electromagnetic field so that the surface-enhanced Raman scattering (SERS) signal can be increased based on GCDs nanocomposites as substrate. Otherwise, the GCDs nanocomposites can also be used to catalyze the oxidation of colourless3,3 ' ,5,5′-tetramethylbenzidine (TMB) to blue oxTMB in the presence of H 2 O 2 , which displays the enhanced peroxidase-like activity compared with alone Au NPs or CDs. The obvious oxidation process of TMB molecules may be monitored by the change of SERS signal during the catalytic reaction. On this basis, GCDs nanocomposites can be further used for detection of glucose. The detection level of glucose is obtained as low as 5 × 10 −7 M. Therefore, this provides a method to detect the glucose based on GCDs nanocomposites as an enzyme mimic.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Bo Ma,Jinglei Bi,Jian Lv,Chuncai Kong,Pengxu Yan,Xintian Zhao,Xiaojing Zhang,Tao Yang,Zhimao Yang
Constructing the heterostructure with noble metals on semiconductors is recognized as a prospective approach to enhance hydrogen generation. In this study, Au-Cu 2 O heterostructure particles (HPs) with unique inter-embedded heterostructures were controllably fabricated by a universal reaction between Cu particles and HAuCl 4 solution. Besides, the boosted catalytic performance from the plasmon effects, Au-Cu 2 O inter-embedded heterostructure exhibits additional structural advantages to promote the photocatalytic property of hydrogen generation overall water splitting. Under the visible light, the H 2 evolution rate of the Au-Cu 2 O HPs is 152 and 22 times higher than that of pure Cu 2 O and traditional Cu 2 O@Au HPs with Au anchored on the surface of Cu 2 O, respectively. On one hand, inter-embedded heterostructure brings more contact areas as the active sites to carry out the direct electron transfer and electromagnetic transfer for the reduction. On the other hand, the finite difference time domain (FDTD) simulations indicate that enhanced electromagnetic fields of Au-Cu 2 O HPs form a netlike structure to maximumly accelerate the transfer of hot electrons and separate the electron–hole pairs. Under the joint action of the two, the inter-embed heterostructure exhibits superior photocatalytic property, demonstrating that this study could instruct the design of other metal–semiconductor photocatalysts.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Linfeng Bai,Kezhu Xu,Wanquan Jiang,Min Sang,Qunling Fang,Shouhu Xuan,Xinglong Gong
Advanced nanocatalysts integrating with high activity and recyclability is one of the most important issues in heterogeneous catalysis. Magnetic hierarchical nanostructures comprising noble metal nanocrystals confined within a protecting penetrable shell will be favored as an efficient candidate toward robust catalytic reactions. This work reports a proof-of-concept magnetic separable nanocatalyst with the polydopamine (PDA)-confined-Au-nanocrystals assembled on the hierarchical surface of Fe 3 O 4 @SiO 2 @γ-AlOOH microflower (Fe 3 O 4 @SiO 2 @γ-AlOOH@Au/PDA). Because of the high surface area of γ-AlOOH hierarchical nanoarchitectures, the loading capacity and dispersity of Au nanocrystals are both improved. These magnetic microflowers present excellent catalytic efficiency and cycling performance in reduction of 4-nitrophenol to 4-aminophenol, which can be ascribed to the superior structure of catalyst. After 9 cycles, the activity of Fe 3 O 4 @SiO 2 @γ-AlOOH@Au/PDA maintains as high as 97.3% due to the protection of PDA shell. In comparison to the spherical Fe 3 O 4 @SiO 2 @Au/PDA, the as-prepared Fe 3 O 4 @SiO 2 @γ-AlOOH@Au/PDA microflowers exhibit quicker catalytic dynamic. The concept of hierarchical nanostructure and penetrable PDA protective layer will be instructive for fabricating high-performance nanocatalysts.
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