RSC Advances
·
2017
·Vol. 7
·期 59
·36923-36928
·
IF 3.108
Yueyue Yin,Yong Yang,Liangzhu Zhang,Yongsheng Li,Zhiyuan Li,Weiwei Lei,Yunfeng Ma,Zhengren Huang
Here, we report a facile synthesis of Pd/Au nano-dogbones (NDBs) by loading massive Pd nanoparticles on the two ends of Au nanorods (NRs) via a seed-mediated method. The as-prepared samples were investigated by using TEM, elemental analysis, UV-vis and FDTD simulation. The photocatalytic activity of Pd/Au NDBs was assessed by dehydrogenation of formic acid under visible-to-NIR light irradiation. The Pd/Au NDBs shows much higher enhanced reaction activity compared with samples with core–shell structure due to the increased electron and hole pair separation and total catalytic sites. More importantly, the introduction of Au NRs broadens the photoresponse range and improves the utilization of sunlight efficiently. This finding provides a rational approach to improve photocatalytic performance by forming dogbone structures via integrating plasmonic metals and conventional catalysts.
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Journal of Materials Chemistry C
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2017
·Vol. 5
·期 31
·7806-7812
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IF 5.256
Lin Chen,Ying Huang,Tian Tian Xing,LingPu Ge,Tong Yang,Bin Chen,Cheng Zhi Huang
Facile detection of melamine in milk was realized through a portable multi-channel sensing device using Au nanoparticles with urchin-like structures as sensing probes. The detection mechanism was based on the aggregation of Au nano-urchins, induced by the formation of Au–N bonding with melamine. The Au nano-urchins were synthesized by a seed-mediated growth method in the presence of hydroquinone, which has the localized surface plasmon absorption at about 680 nm. The results showed that the melamine detection was environment pH dependent. The optimal melamine detection condition occurred when the pH of the BR buffer was 5.72. A better selectivity to melamine was fulfilled when compared with its structurally similar compounds: cytosine, uracil, and thymine. The multi-channel sensing device has a detection limit of 18 nM for melamine in milk, which could meet the requirement for monitoring the melamine amount in milk.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2016
·
IF 8.328
Jiabai Cai,Xueqing Wu,Shunxing Li,Fengying Zheng
Visible-light-driven photocatalysis as a green technology has attracted a lot of attention due to its potential applications in environmental remediation. Although TiO 2 is the most popular photocatalyst, the lack of visible light utilization and a low efficiency of electron-hole separation should be overcome. Therefore, Au nanoparticles (NPs) as cocatalyst were controllably loaded between the double-shell or into CeO 2 shell (as photocatalyst and oxygen buffer) and then a novel visible-light-driven TiO 2 @CeO 2 nanocomposite was prepared, using functionalized polystyrene spheres, sol-gel, hydrothermal reaction, and calcination. The presence of TiO 2 shell, Au NPs and CeO 2 shell were confirmed by EDX and electron energy loss mapping analysis. Under visible-light irradiation, the photo-degradation rate constant k (min −1 ) was in the order of TiO 2 @Au@CeO 2 (0.026) > TiO 2 @CeO 2 /Au (0.021) > TiO 2 @CeO 2 (0.014) > CeO 2 (0.0091) > TiO 2 (0.0046) > P25 (0.0034). Compared with P25, TiO 2 @CeO 2 , and TiO 2 @CeO 2 /Au, the visible-light photocatalytic activity of TiO 2 @Au@CeO 2 for the photo-degradation of organic pollutant and photo-reduction of Cr(VI) were the highest. This result was attributed to the combination of TiO 2 and CeO 2 , the double-shelled and sandwiched nanostructure and the addition of Au NPs as electron trap site and surface plasmon resonance-sensitizer, which could reduce the recombination of the electron-hole and induce the visible light absorption. The major obstacle of heterogeneous photocatalysis could be resolved. The photo-degradation rate of 95% was achieved by TiO 2 @Au@CeO 2 , which exhibited an increase of 63% compared to Degussa P25 TiO 2 . The photo-degradation activity of TiO 2 @CeO 2 /Au was improved by Au NPs loaded on outer shell of TiO 2 @CeO 2 /Au but limited by their stability. This work confirmed the importance of controllable location of the noble metals as cocatalysts.
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NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 22
·13472-13482
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IF 3.269
Mengqiu Huang,Yiwei Zhang,Yuming Zhou,Chao Zhang,Shuo Zhao,Jiasheng Fang,Yan Gao,Xiaoli Sheng
This work reports a novel type of sandwich-like hollow Au-based nanocatalyst, including a TiO2–ZrO2 shell, a hollow CeO2 core and Au nanoparticles of 2–5 nm. Uniform crystal ceria hollow nanostructures were synthesized using a simple one-step hydrothermal method without a template. Then binary TiO2–ZrO2 coated Au nanocatalysts were prepared via a facile bottom-up synthesis method. The structural features of the catalysts were characterized by several techniques, including SEM, TEM, EDX, FTIR, BET, XRD, UV-vis and XPS analyses. Using the reduction of 4-nitrophenol by NaBH4 as a model reaction, the TiO2–ZrO2/Au/CeO2 microspheres showed a superior catalytic activity and thermal stability compared with a pure TiO2 or ZrO2 layer. In addition, TiO2–ZrO2/Au/CeO2 microspheres calcined at 700 °C presented the highest thermal stability and reactivity. These comparative results were mainly attributed to the synergistic effect among the mixed oxide, hollow CeO2 core and Au NPs and the sandwich-like structure. As a consequence, this unique nanocatalyst will open a promising route for the fabrication of hollow binary-metal-oxide materials for future research and has great potential for other applications.
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Inorganic Chemistry Frontiers
·
2017
·Vol. 4
·期 12
·2088-2096
·
IF 4.036
Benxia Li,Renshan Wang,Xiankun Shao,Liangzhi Shao,Baoshan Zhang
In this work, a new design of ternary core–shell nanostructures of Au@ZnO–Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic performance. In the ternary hybrid nanostructures, ZnO provides photo-generated carriers with higher redox ability, under UV-visible light, and Au nanocrystals perform the plasmonic hot electron injection as well as the local electromagnetic field enhancement of ZnO photoexcitation. Meanwhile, the Pd NPs can efficiently trap the generated electrons to govern the directional separation of the charge carriers. The efficient charge carrier separation in the ternary hybrid nanostructures was confirmed by steady-state PL spectra, time-resolved PL decay spectra, and transient photocurrent responses. The photocatalytic activity of the Au@ZnO–Pd nanostructures was evaluated by photodegrading phenol and methylene blue, respectively, under simulated sunlight (λ = 360–780 nm), and the results showed that the Au@ZnO–Pd nanostructures gained a great enhancement of photocatalysis compared with ZnO, ZnO–Pd and Au@ZnO. Moreover, the effect of Pd loading content in the Au@ZnO–Pd nanostructures on the photocatalytic efficiency was studied within a certain range, indicating that the Au@ZnO–Pd photocatalyst with ∼1.8 wt% Pd loading exhibited the best photocatalytic activities for photodegrading both phenol and methylene blue. The generation and effect of active species in the photocatalytic process were investigated using ESR testing and radical scavenging experiments. As a consequence, the integration of the ternary Au@ZnO–Pd core–shell nanostructures could achieve collective effects to greatly increase the photocatalytic efficiency.
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Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 41
·21903-21908
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IF 8.867
Binbin Jiang,Zeyuan Tang,Fan Liao,Haiping Lin,Shunkai Lu,Youyong Li,Mingwang Shao
The hydrogen evolution reaction (HER) is a fundamental electrochemical reaction to produce hydrogen gas from the electrolysis of water, and has been regarded as an attractive solution to many energy challenges. In the past few decades, platinum has been widely demonstrated to split water into hydrogen gas at high reaction rates and low overpotentials. Nevertheless, decreasing the loading of Pt in the designed electrocatalysts is very significant. However, with low Pt loading, it is challenging to maintain excellent catalytic performance. Here we report a Pt–Au–Si ternary nanocomposite as a highly active catalyst for the HER. The optimal composition of Pt–Au–Si was determined to be 7.2 : 31.3 : 61.5 (Pt : Au : Si, mass ratio) with a Tafel slope of only 24 mV dec−1. To be specific, the mass activity of the Pt–Au–SiNW-2 catalyst was 6.5 fold that of a 40 wt% Pt/C catalyst at an overpotential of 60 mV. More importantly, the cathodic current density even surpassed 40 wt% Pt/C when the overpotential was larger than 0.17 V (the corresponding current density was 108 mA cm−2). The outstanding catalytic performance might be derived from the synergy of the respective properties of the three components: the fast hydrogen adsorption rate on Pt, the quick migration of the adsorbed hydrogen atoms on Au and the rapid hydrogen evolution rate on Si. This research opens up a novel strategy to prepare highly efficient catalysts for electrochemical hydrogen evolution reactions.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
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2017
·Vol. 17
·期 7
·5109-5114
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IF 1.483
Fang Cheng,Cao Liangli,Chen Zhencheng
A disposable electrochemical immunosensor for detection of human alpha-fetoprotein (AFP) has been developed in this study, using monoclonal antibody against AFP and horseradish peroxidase co-modified colloidal gold nanoparticles (Ab-Au-HRP) as trace label and screen-printed carbon electrodes
(SPCEs) as signal transducers. The immunosensor was based on a sandwich immunoassay scheme in which the nanoprobe Ab-Au-HRP was dispensed on the polyester membrane as conjugate pad. The other monoclonal antibody against AFP, as capture antibody, was immobilized onto the nitrocellulose membrane
which was mounted on the carbon surface of the screen-printed electrodes. An absorbent paper was mounted downstream to draw the sample to successively flow through the conjugate, capture and absorbent pads. The resulting sandwich immune reaction was evaluated by electrochemical detection,
through addition of a single-component substrate for HRP. Under optimum conditions, the current value was linearly increased with an increased AFP concentration from 0.5 to 350 ng/mL, at a relatively low detection limit of 0.25 ng/mL at 3 sigma. Excellent analytical performance, fabrication
reproducibility and operational stability for the proposed immunosensor indicated its promising application in clinical diagnostics and self-exams.
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ADVANCED FUNCTIONAL MATERIALS
·
2015
·Vol. 25
·期 31
·5006-5015
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IF 11.805
Rui Tian,Shitong Zhang,Mingwan Li,Yuqiong Zhou,Bo Lu,Dongpeng Yan,Min Wei,David G. Evans,Xue Duan
Gold nanoclusters (Au NCs) stand for a new type of fluorescent nanomaterials with outstanding optical properties due to their discrete electronic energy and direct electron transition. However, relative low quantum yield (QY) of Au NCs in aqueous or solid state has limited their photofunctional applications. To improve the fluorescent performances of Au NCs and find an effective approach for the fabrication of Au NCs-based films, in this work, Au NCs are localized onto 2D layered double hydroxides (LDHs) nanosheets via a layer-by-layer assembly process; the as-fabricated (Au NCs/LDH) n ultrathin films (UTFs) show an ordered and dense immobilization of Au NCs. The localization and confinement effects imposed by LDH nanosheets induce significantly increased emissive Au(I) units as confirmed by X-ray photoelectron spectroscopy and periodic density functional theoretical simulation, which further results in promoted QY (from 2.69% to 14.11%) and prolonged fluorescence lifetime (from 1.84 µs to 14.67 µs). Moreover, the ordered (Au NCs/LDH) n UTFs exhibit well-defined temperature-dependent photoluminescence (PL) and electrochemiluminescence (ECL) responses. Therefore, this work supplies a facile strategy to achieve the immobilization of Au NCs and obtain Au NCs-based thin films with high luminescent properties, which have potential applications in PL and ECL temperature sensors.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2015
·
IF 2.752
Mei Lei,Wei Wu,Lingling Sun,Qingyong Tian,Changzhong Jiang,Xiangheng Xiao
According to relative energy band positions between noble metals of Au, Ag, and wide bandgap semiconductor SnO 2 , Au, and Ag nanoparticles (NPs) modified hollow SnO 2 NPs were designed. Firstly, the hollow SnO 2 NPs have been synthesized by employing the silica template-assisted hydrothermal methods, then Au and Ag were coated on the surface of SnO 2 to form the core–shell structures, respectively. The morphology, composition, and optical properties of as-prepared samples have been investigated by various analytic methods. Subsequently, the photocatalytic reaction to Rhodamine B (RhB) dye under simulated-sunlight irradiation was employed to investigate their photocatalytic performance, the results demonstrate the metal–semiconductor with direct Schottky contact exhibited remarkable photocatalytic activity . The finite difference time domain (FDTD) calculation results illustrate the introduced and decorated Au and Ag NPs could enhance the harvesting abilities for visible light. We envision the aforementioned synthesized strategy and catalytic results are used to the designing and application of other metal–semiconductor system.
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Plasmonics
·
2013
·Vol. 8
·期 2
·1003-1009
·
IF 2.425
Zhu Jian,Gao Hong-wen,Li Jian-jun,Zhao Jun-wu
Carcinoembryonic antigen (CEA) was used as a separator to prevent the Rhodamine 6G (R6G)-induced aggregation of colloidal gold nanoparticles. The destroyed aggregation has been monitored by measuring the absorption and resonance light scattering peaks corresponding to the longitudinal surface plasmon resonance (SPR) of the chain-like aggregated gold nanoparticles (AuNPs). It was found that the pre-adding of CEA with different concentrations to the gold colloids before mixing them with R6G could lead to the longitudinal SPR peak decrease and blue shift. By analysing the intensity changing and wavelength shifting of the absorption spectra, CEA could be detected in a linear range from 0.2 to 4 ng/mL, and the limit of detection reaches to 0.1 ng/mL. The sensitivity of the CEA concentration dependent shifting and quenching of the plasmonic absorption and scattering corresponding to the AuNPs aggregation presents a well potential application of biologic spectral sensing.
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RSC Advances
·
2015
·Vol. 5
·期 103
·84980-84987
·
IF 3.84
Hongda Chen,Fuyao Liu,Zhen Lei,Lina Ma,Zhenxin Wang
Herein, we present the synthesis and application of a new type of graphene-based magnetic and plasmonic nanocomposite for magnetic-field-assisted drug delivery and chemo-photothermal synergistic therapy. The nanocomposites were prepared via conjugation of the PEGylated Fe2O3@Au core/shell nanoparticles (Fe2O3@Au NPs) with reduced graphene oxide (rGO). The hybrid nanostructures (rGO–Fe2O3@Au NPs) are superparamagnetic and show great photothermal conversion efficiency under 808 nm near-infrared (NIR) laser irradiation and high drug loading ability (1.0 mg mg−1). MTT cell viability assay demonstrates that the chemotherapeutic drug, doxorubicin loaded rGO–Fe2O3@Au NPs (DOX–rGO–Fe2O3@Au NPs) have synergistic interaction between photothermal therapy (PTT) and chemotherapy. Furthermore, in vitro studies using HeLa cells show that the chemo-photothermal therapeutic efficacy of DOX–rGO–Fe2O3@Au NPs can be dramatically improved by the assistance of magnetic-field-guided drug delivery.
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ELECTROCHEMISTRY COMMUNICATIONS
·
2014
·
IF 4.287
De-Man Han,Lu-Yi Jiang,Wen-Yuan Tang,Jing-Juan Xu,Hong-Yuan Chen
A novel photoelectrochemical (PEC) sensor for mercury ions (Hg 2 + ) was fabricated based on the energy transfer (ET) between CdS quantum dots (QDs) and Au nanoparticles (NPs) with the formation of T–Hg 2 + –T pairs. In the presence of Hg 2 + ions, a T-rich single-strand (ss) DNA labeled with Au NPs could hybridize with another T-rich ssDNA anchored on the CdS QDs modified electrode , through T–Hg 2 + –T interactions, rendering the Au NPs in close proximity with the CdS QDs and hence the photocurrent decrease due to the ET between the CdS QDs and the Au NPs. Under the optimal condition, the photocurrent decrease was proportional to the Hg 2 + concentration, ranging from 3.0 × 10 − 9 to 1.0 × 10 − 7 M, with the detection limit of 6.0 × 10 − 10 M.
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