JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Jiaxuan Fan,Lingxiang Cheng,Yanan Liu,Yufei He,Yanfei Wang,Dianqing Li,Junting Feng
Photocatalytic reduction of CO 2 with H 2 O into CH 4 is a promising way to realize solar energy utilization and CO 2 conversion, in which the key issue is how to enhance and couple CO 2 reduction as well as H 2 O oxidation. In this work, we precisely fabricated a binary functional photocatalyst by loading Au@Pd nanoparticles onto V O -rich TiO 2 through a surfactant-free deposition-reduction method, whose fine structure was confirmed by aberration-corrected HAADF-STEM, EELS, EPR and XPS. Combining photocatalytic performance with a series of in situ FTIR measurements, we clarified the role of metallic sites and semiconductor support in coupling CO 2 reduction and H 2 O oxidation. Specifically, H 2 O oxidation process was facilitated by the V O -rich TiO 2 to contribute more protons, followed by the activation of CO 2 and protons primarily by the metallic Au@Pd sites to form the surface bounded Au@Pd-CO 2 − and Au@Pd-H species. By adjusting the ratio of Au@Pd nanoparticles and V O concentration to manipulate the Au@Pd-CO 2 − /Au@Pd-H ratio, CH 4 yield of 26.32 μmol/(g·h) and selectivity of electron toward CH 4 of 96% can be observed with minimal concomitant H 2 generation. These findings could open a feasible and universal route to enhance the photocatalytic efficiency of CO 2 conversion.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
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IF 7.65
Xia Zhou,Guangqiang Liu,Hongwen Zhang,Yue Li,Weiping Cai
A core–shell configuration of the zeolite imidazole framework (ZIF-8) wrapped urchin-like Au-Ag alloyed nanocrystals (UAANs) were designed and fabricated via adding the pre-formed plasmonic nanoparticles into the ZIF-8 precursor solution with hexadecyltrimethyl ammonium bromide (CTAB). The UAANs are about 100 nm in size with high-density tips. The ZIF-8 shell layer is nanoporous and can be controlled in thickness from 10 nm to 40 nm by the CTAB concentration. Importantly, such ZIF-8 wrapped UAANs can be used as the highly efficient surface enhanced Raman scattering (SERS) substrates for detection of the trace hexachlorocyclohexane (HCH) molecules. The ZIF-8 shell layer with an appropriate thickness (-∼20 nm) can evidently increase the SERS performance of the UAANs to the trace γ-HCH and α-HCH. Such wrapping-enhanced SERS effect significantly increases, by a power function, with the decreasing HCH concentration, especially in the concentration below 10 −6 M, which is attributed to the ever-increasing enrichment effect to the HCH molecules. The detection limit is down below 1.5 ppb. This work presents a highly efficient substrate for the SERS-based detection of the trace HCH, and also displays the potential application in the SERS detection of volatile small molecules.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
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IF 3.375
Xiangzhan Meng,Yongqiang Zhang,Zengxi Li,Hui Wang,Suojiang Zhang
Au supported on monoclinic ZrO2 (Au/m-ZrO2) prepared by deposition–precipitation method showed excellent catalytic performance in the aerobic oxidation of amino alcohols to amino acids, i.e., glycine, alanine, serine, β-alanine, and 2-aminobutyric acid. The Au particle size and valence distribution of the gold species were adjusted by calcination temperature, as demonstrated by XRD, TEM, UV–vis DRS, XPS, and H2-TPR, which significantly influenced the catalytic activity but not the selectivity of amino acids. Metallic gold atoms on the surface were shown to be the active sites by the correlation between reaction rate per mole of metallic Au and Au particle size. The kinetics of oxidation of monoethanolamine (MEA) was studied in detail, and the results indicated that MEA oxidation is a first-order reaction with an activation energy of 52.8 kJ·mol–1.
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Nanoscale
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2019
·Vol. 11
·期 18
·9115-9124
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IF 6.97
Yunfei Tang,Xiaoqiang Liu,Hejie Zheng,Liwei Yang,Lele Li,Si Zhang,Yanmei Zhou,Subbiah Alwarappan
In this work, a novel photoelectrochemical (PEC) aptasensor was developed for the sensitive detection of aflatoxin B1 (AFB1) based on a resonance energy transfer strategy between the Ce-TiO2@MoSe2 heterostructure and Au nanoparticles (AuNPs). The Ce-TiO2@MoSe2 composite was obtained by growing MoSe2 nanosheets on a TiO2 nanocube doped by the Ce element with a facile hydrothermal method. The composite effectively extended the absorption of TiO2 to the visible region and avoided the self-aggregation of MoSe2 nanosheets, leading to the excellent photocurrent response under visible light excitation. The PEC aptasensor was then fabricated by immobilizing the Ce-TiO2@MoSe2 composite on an ITO electrode, followed by the modification of the aminated AFB1 aptamer. An AuNP-labeled DNA sequence was subsequently hybridized with the aptamer to fabricate a sandwich structure, which was destroyed after the introduction of AFB1, decreasing the amount of the energy acceptor (AuNPs) at the electrode surface. Accordingly, the photocurrent was increased with the increase of AFB1 concentration. Under the optimal conditions, the PEC aptasensor showed a wide linear range of 0.03–200 ng mL−1 and a low detection limit of 0.01 ng mL−1 for AFB1 determination.
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RSC Advances
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2019
·Vol. 9
·期 19
·10958-10965
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IF 3.049
Yang Zhang,Ruixi Bai,Zhigang Zhao,Qiuxia Liao,Peng Chen,Wanghuan Guo,Chunqing Cai,Fan Yang
In this study, a variety of diglycolic acid-functionalized gold nanoparticle (Au NP) probes are reported, which are highly sensitive for the detection of chromium ions, Cr(VI) ions, at low concentrations in aqueous solutions based on the application of surface plasmon resonance (SPR) theory. Due to its outstanding affinity for Cr(VI) ions, the capped diglycolic acid would induce the aggregation of the NP probes upon encountering them; this was evidenced by the obvious red-shifting of the SPR peak and the enlarged size of the NPs. For the same reason, the selectivity of the probe for Cr(VI) against other heavy metal ions was found to be remarkable. Under optimized conditions, the probe showed the limit of detection (LOD) of 0.32 ppb for Cr(VI) and a linear detection scale ranging from 0.32 ppb to 0.1 ppm. To the best of our knowledge, this is probably the lowest LOD reported for Cr(VI) detection among those of the methods based on SPR.
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Nanomaterials
·
2019
·Vol. 9
·期 2
·229
·
IF 4.034
Qianqian Wang,Xiaofei Qin,Liping Geng,Yan Wang
A label-free electrochemical aptasensor was fabricated to sensitively determine malachite green (MG) based on Au nanoparticles/graphene quantum dots-tungsten disulfide nanosheet composite film modified glassy carbon electrode (AuNPs/GQDs-WS2/GCE). A facial strategy for the self-assembly of graphene quantum dots (GQDs) on tungsten disulfide nanosheets (WS2) was developed to fabricate 0D/2D nanocomposites. As-prepared GQDs-WS2hybrids exhibited significantly enhanced electrocatalytic properties, and were first used as electroactive materials to construct electrochemical aptasensor. The AuNPs/GQDs-WS2/GCE was prepared through depositing Au nanoparticles on the surface of the GQDs-WS2film, which acted as the electrochemical sensing matrix to covalently immobilize the aptamers of MG via the Au–S bond. In this label-free proposal, the aptasensor was applied to detect MG by monitoring voltammetric signal resulted from electrochemical oxidation of the MG captured by the aptamer. Under the optimized conditions, the aptasensor showed a wide linear range from 0.01 to 10 μM for MG detection with a low detection limit of 3.38 nM (S/N = 3). The method was applied to determination of MG in spiked fish samples and gave satisfactory results.Keywords:electrochemical aptasensor;tungsten disulfide nanosheet;graphene quantum dots;Au nanoparticles;malachite green
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TALANTA
·
2019
·
IF 4.916
Jie Chang,Amin Zhang,Zhicheng Huang,Yunsheng Chen,Qian Zhang,Daxiang Cui
The rapid identification of living cancer cells is highly crucial for cancer diagnosis, prognosis, and treatment monitoring. However, it is a great challenge to develop an effective way for rapid identification and imaging of cancer cells in a living state. Moreover, synthesis of monodisperse nanoparticles (NPs) with high sensitive surface-enhanced Raman scattering (SERS) activity is also a tough work. Herein, we creatively reported a convenient method to synthesize the novel NPs as the substrate of SERS sensors, which possessed a gold nanobipyramid core and silver nanorod shell. These gold nanobipyramid core and silver nanorod shell NPs (Au NBP@Ag NRs) were further modified with 4-mercaptobenzoicacid (4-MBA, Raman reporter molecule) and then conjugated with reduced bovine serum albumin (rBSA) and folic acid (FA) on their surfaces, to finally acquire Au NBP@Ag NR-MBA-rBSA-FA nanoprobes. In this system, With the enhancement factor (EF) of Au NBP@Ag NRs was about 4 × 10 7 , it could significantly enhance Raman signal for Raman reporter molecules, and 4-MBA molecules performed high SERS signals based on their structures; the nanoprobes have favorable specificity and biocompatibility owing to the modification of rBSA which effectively avoided the nonspecific attachment of non-targeted cells. Moreover, the obtained SERS nanoprobes have excellent sensitivity for gastric cancer cells (MGC-803 cells) due to the conjugation of folic acid. Thus, the finally obtained Au NBP@Ag NR-MBA-rBSA-FA nanoprobes possess excellent detection efficiency for living MGC-803 cells. Therefore, our synthesized nanoprobes exhibit ultrasensitive SERS-activity, excellent specificity and superior cancer cells targeting ability, which could be applied for rapid identification and Raman imaging of living cancer cells via the SERS signal detection of the nanoprobes.
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Materials
·
2019
·Vol. 12
·期 12
·1950
·
IF 2.972
Shengding Chang,Muwei Ji,Changxu Yan,Kai Zhang,Qian Deng,Jian Xu,Caizhen Zhu,Bo Li,Jin Wang
KTaO3/Au hetero-nanostructures were synthesized by in-situ reduction of HAuCl4on the surface of hydrothermally-grown KTaO3sub-micron cubes. The concentration of Au source was found to be a critical factor in controlling the hetero-nucleation of Au nanoparticles on the surface of KTaO3sub-micron cubes. Loading of Au particles on KTaO3nanocrystals enriched KTaO3additional UV-vis absorption in the visible light region. Both KTaO3and KTaO3/Au nanocrystals were shown to be active in the photo-degradation of p-nitrophenol, while the loading of Au on KTaO3clearly improved the photo-degradation efficiency of p-nitrophenol compared to that on bare KTaO3nanocrystals, probably due to the improved light absorption and charge separation.Keywords:in-situ synthesis;KTaO3/Au hetero-nanostructures;concentration of Au source;photo-degradation of p-nitrophenol
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RSC Advances
·
2019
·Vol. 9
·期 31
·17783-17790
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IF 3.049
Ling Chen,Rui Li,Ping Yang
We report a sensitive and selective localized surface plasmon resonance (LSPR) nanoprobe for the detection of mercuric ions (Hg2+) using gold/silver core–shell nanorods as an optical nanosubstrate. Sulfide can quickly react with silver atoms to generate Ag2S at room temperature in the presence of oxygen. The transformation from Ag shell to Ag2S on the nanorod surface results in its LSPR absorption band shifting to a longer wavelength, which is attributed to their different refractive indices. Interestingly, the morphology also changed from a rod-like to dumbbell shape. However, in the presence of Hg2+, this morphology transformation is inhibited because the sulfide reacts with free Hg2+ prior to the Ag atoms. The amount of Ag2S reduced with the increasing concentration of Hg2+, and the absorption band shift was also decreased. According to this “rod-like to dumbbell or not” shape change, a sensitive and selective LSPR nanoprobe was established, assisted by UV-Vis absorption spectroscopy. The detection limit of this probe for Hg2+ was as low as 13 nM. The efficiency of this probe in complex samples was evaluated by the detection of Hg2+ in spiked water samples.
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SENSORS AND ACTUATORS B-CHEMICAL
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2019
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IF 6.393
Danni Wang,Yingzhi Zhang,Xiayu Zhao,Zhangrun Xu
Telomerase aberrant activation is a critical feature in the vast majority of cancers. To visualize telomerase expression level in tumor cells, we developed a plasmonic colorimetric sensor for highly sensitive detection of telomerase activity by integrating an excellent etching substrate Au nanobipyramids (Au NBPs) with a liposome-based signal amplification strategy. Upon telomerase-triggered extension, the telomerase activity was converted into the amount of the attached horseradish peroxidase-encapsulated liposomes (HRP-Ls) on the surfaces of magnetic beads. Afterwards, HRP was liberated from the liposomes following the addition of H 2 O 2 -3,3′,5,5′-tetramethylbenzidine sulfate (TMB) substrate, and then the oxidation reaction between H 2 O 2 and TMB was initiated to form TMB 2+ . The morphological evolution of Au NBPs relied on the TMB 2+ -mediated etching reaction, which gave rise to tremendous localized surface plasmon resonance (LSPR) responses and concomitant tonality transitions. Benefiting from cascaded signal amplification capacity of HRP-Ls and the intriguing optical properties of Au NBPs, an impressive sensitivity toward telomerase was obtained with detection limits equivalent to 1 HeLa cell for LSPR peak measurement and a visual detection limit of 20 HeLa cells. Furthermore, a facile and portable kit was fabricated for visual evaluation of telomerase activity in different cell lines.
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
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2019
·Vol. 2019
·期 22
·2761-2767
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IF 2.578
Hongchen Yang,Shengbo Zhang,Mei Li,Xiao Liu,Jinyu Han,Xinli Zhu,Qingfeng Ge,Hua Wang
Graphical Hollow N-doped carbon nanocages incorporating Au and ZnO nanoparticles derived from ZIF-8 were synthesized. Au 0.40 -ZnO/CN incorporates Au and ZnO nanoparticles. Under visible light irradiation, Au 0.40 -ZnO/CN exhibits a significantly enhanced H 2 production rate from formaldehyde alkaline solution, which is 12 times and 2.6 times of those of ZnO/CN and Au/CN, respectively. Hollow carbon nanostructured materials incorporating metals or metal oxides have attracted considerable interest in photocatalysis. Herein, novel hollow N-doped carbon nanocages incorporating Au and ZnO nanoparticles derived from ZIF-8 were successfully synthesized. Firstly, ZIF-8 nanocrystals were treated with chloroauric acid solution (HAuCl 4 ) to produce hollow Au X @ZIF-8 cubes through acid etching of cores and cation exchange. Then, the Au X @ZIF-8 cubes were used as precursors to obtain Au X -ZnO/CN after pyrolysis in a N 2 atmosphere. The resulting Au 0.40 -ZnO/CN had a uniform hollow structure with ≈ 30 nm shells conformal to ZIF-8 dimension while incorporating ≈ 5 nm nanoparticles of Au and ZnO and exhibited remarkable photocatalytic activity and excellent recyclability for hydrogen production from formaldehyde (HCHO) alkaline solution under visible light irradiation. The results demonstrated that incorporation of Au greatly improves the visible light absorption and charge separation via SPR effect. Furthermore, the ZIF-8-derived hollow N-doped carbon cages can expose more uniformly disperse active sites with conductive support. The methodology used here provides a novel approach for preparing hollow hybrid carbon materials with visible-light-driven photocatalytic applications.
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Food Analytical Methods
·
2018
·Vol. 11
·期 11
·3095-3102
·
IF 2.245
Wang Hai-Bo,Li Yang,Bai Hong-Yu,Zhang Zi-Ping,Li Yong-Hong,Liu Yan-Ming
In this work, a rapid and label-free fluorescent sensing method has been established for tetracycline (TC) detection by using poly(adenine) (poly A) DNA-templated Au nanoclusters (AuNCs) as fluorescence indicator. The obtained AuNCs exhibited excellent fluorescence intensity and good stability. In the presence of tetracycline, the fluorescence intensity of AuNCs was obviously reduced due to the interactions between the tetracycline and the poly A DNA-templated AuNCs. Under the optimum conditions, the strategy permitted sensitive detection of tetracycline in a linear range from 0.1 to 60 μM and with a limit of detection of 20 nM. In addition, the sensor was successfully applied to determinate the tetracycline content in milk samples. More importantly, it could be easily performed within 10 min at room temperature. Thus, it could provide a rapid, convenient, label-free, and high-sensitive fluorescent platform for tetracycline detection.
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