Analytical Methods
·
2016
·Vol. 8
·期 17
·3564-3569
·
IF 1.915
Chunzhi Xuan,Qiao Xia,Juanjuan Xu,Qinghong Wang,Xia Lin,Yingzi Fu
The nanocomposite (Au@BSA) which was synthesized using gold nanoparticles (AuNPs) and bovine serum albumin (BSA) was used as an electrochemical sensing layer for chiral recognition of propranolol (PRO). Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) spectroscopy and amperometric testing technique were employed to characterize the Au@BSA nanocomposite. Differential pulse voltammetry (DPV) and atomic force microscopy (AFM) were used to assess the enantioselective performance of the fabricated interface, and the optimal experimental conditions, such as acidity and incubation time were also discussed. The results showed that after the modified interface interacted with PRO enantiomers larger discrepancy was obtained from S-PRO, and linear electrochemical responses to PRO enantiomers were obtained from 1.0 × 10−5 to 5.0 × 10−3 mol L−1 with a detection limit of 3.3 × 10−6 mol L−1 (S/N = 3). To gain more information on the role of gold nanoparticles (AuNPs) and bovine serum albumin (BSA) in the chiral recognition of PRO enantiomers, the interface fabricated using AuNPs or BSA was also allowed to interact with PRO enantiomers, and no obvious signal discrepancy was obtained. The results suggested that only Au@BSA could be employed for the enantioselective recognition of PRO enantiomers.
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Nanoscale
·
2018
·Vol. 11
·期 3
·1169-1176
·
IF 7.233
Ge Gao,Qiaoyue Xi,Yanqun Zhang,Manyu Jin,Yongxia Zhao,Cunqi Wu,Hua Zhou,Pengran Guo,Jingwei Xu
A surface-engineered heterogeneous catalyst with a controllable catalytic interface is the most straightforward approach for boosting catalytic activity. However, changing the surface structure of nanocrystals and ensuring the exposure of active sites still face challenges. In this work, a three-dimensional self-supported catalyst with ultrathin Au nanoclusters encapsulated in Cu-doped ZIF-8 nanorod arrays on Ni foam (AuNC@ZIF-8(Cu) NRAs) is synthesized by a bottom-up strategy. This catalyst exhibits high catalytic activity with a 98% conversion of 4-nitrophenol to 4-aminophenol within 6 min. Meanwhile, it also has superior catalytic activity for other nitrobenzene compounds, such as 3-nitrophenol, 2-nitrophenol and p-nitroaniline. Furthermore, after 10 cycles, the catalytic performance and morphology of the catalyst have no obvious change. The excellent catalytic performance and stability of AuNC@ZIF-8(Cu) NRAs are attributed to the synergistic effect of ZIF-8(Cu) and AuNC. The doping of Cu in the ZIF-8 framework effectively alters the superficial electronic structure of encapsulated Au nanoclusters, which can dramatically promote the formation of gold hydride intermediates. The confinement effect of the porous ZIF-8 framework makes the AuNC active sites more stable and accessible to substrates. This method can be used to alter the activity of the catalyst by regulating the metal ion coordination of MOFs to influence the surface properties of encapsulated AuNC and opens the door to the rational design of new catalysts.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Yibin Bu,Yafeng Chen,Guiming Jiang,Xinmei Hou,Shun Li,Zuotai Zhang
To design an efficient catalyst for HCHO oxidation, it requires good understanding of the correlation between structural properties of catalyst and the reaction mechanism. We investigated performance of commercial CeO 2 (CeO 2 -C) and nanorod CeO 2 (CeO 2 -R) and the corresponding Au/CeO 2 catalysts in HCHO oxidation. Reactivity tests showed that Au/CeO 2 -R is highly efficient and stable in HCHO oxidation at room temperature, which is attributed to the highly active Au-CeO 2 -R interface. The strong interaction between Au and CeO 2 -R greatly promotes the creation of oxygen vacancies and Au 3+ near the interface, which promotes the formation of formate. The conversion of formate can follow both a decomposition and a direct oxidation pathway, which is remarkably enhanced by the coexistence of Au 3+ and oxygen vacancies. In addition, formate accumulation and Au particles aggregation led to deactivation. The presence of humidity promotes the oxidation of formate, which improves the reactivity and stability of Au/CeO 2 in HCHO oxidation.
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2019
·
IF 2.722
Xiaoxue Lian,Yan Li,Junwu Zhu,Yunling Zou,Dongmin An,Qiong Wang
Stannic oxide nanoparticles with the different Au decorating contents are prepared by a simple hydrothermal method in this paper. The products are characterized by X-ray diffraction (XRD), energy dispersive spectrum (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD patterns reveal that all the products are tetragonal phase of rutile SnO 2 crystal structure. The gas-sensing performance of the Au-decorated SnO 2 nanoparticles for volatile organic compounds (VOCs) are studied. At its optimal operation temperature of 240 o C, the sensing properties of the Au-decorated SnO 2 nanoparticles to n-buthanol gas show a good gas sensing performances as low detection limit (1ppm), good selectivity and good repeatability. The highest sensing response of 6.0 at. % Au-decorated SnO 2 nanoparticles (251.23 for 200 ppm to n-buthanol) is over 21 times higher than that of pure SnO 2 (11.5). All results prove the potential of using Au-decorated SnO 2 for n-buthanol gas detection.
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ACS Catalysis
·
2022
·
IF 13.7
Yanwei Cao,Yao Peng,Danyang Cheng,Lin Chen,Maolin Wang,Cheng Shang,Lirong Zheng,Ding Ma,Zhi-Pan Liu,Lin He
The conversion of carbon monoxide (CO) into high-value organic molecules has long been pursued by both industry and academia. One of the central challenges is to realize carbon–carbon coupling with high selectivity for CO insertion. We report here a highly selective Au/ZnO composite catalyst for one-step oxidative coupling of CO with secondary amines, producing oxamides. The reaction is >99% selective under ambient conditions, which exhibits a subtle change of catalyst activity over ∼120 h in a fixed-bed reactor. A combination of microscopic and spectroscopic studies (including X-ray photoemission spectroscopy, X-ray absorption spectroscopy, CO-Fourier transform infrared spectroscopy, and aberration-corrected high-angle annular dark-field scanning transmission electron microscopy) and machine learning reveal that the active site is the Au–ZnO interface with a Au nanocluster attached to the ZnO support via nonstoichiometric ZnOx (x > 1) linkages. The reaction mechanism and key reaction intermediates were confirmed by density functional theory calculations and in situ diffused reflectance infrared Fourier transform spectroscopy signals. Our results open an avenue in heterogeneous catalysis to achieve the ambient-condition CO transformation by exploiting the interfacial synergistic effects.
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 4
·1-9
·
IF 5.833
Li Li,Li Siqun,Yu Xinjie,Chen Zhengbo
A colorimetric sensing method is described for discrimination of multiple antioxidants based on core-shell Au@Ag nanocubes (NCs). In order to extract data-rich colorimetric responses from the sensor array, three different concentrations of chloroaurate acid (HAuCl 4 ) were employed as sensing elements. Interestingly, Au 3+ ions can be reduced to different valence states (i.e., Au(0) and Au(I)) by different antioxidants, and thus effectively inhibit the oxidation etching process of Au@Ag NCs by Au(III) ions to varying extents, generating diverse colorimetric responses (color and absorbance). This enables identification of the six antioxidants at 10 nM via linear discriminant analysis (LDA) with relative standard deviation (RSD) of 2.52% ( n = 3). The discrimination ability of the sensor array was further evaluated in antioxidant binary and multicomponent mixtures. Remarkably, identification of these six antioxidants spiked in urine was realized with 100% of accuracy. Graphical abstract
Schematic presentation of colorimetric assay for antioxidants based on three chloroauric acid/Au-Ag nanocubes.
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Journal of Physical Chemistry C
·
2018
·
IF 4.484
Le Zhou,Hongwen Zhang,Haoming Bao,Guangqiang Liu,Yue Li,Weiping Cai
A flexible route is presented for the controlled decoration of the Au nanoparticles (NPs) on the spherical MoS2 particles, just by dropping the HAuCl4 aqueous solution into the hydrothermal reaction-induced MoS2 colloidal solution at room temperature. In the absence of surfactants in the colloidal solution, it has been found that the obtained products are mostly the MoS2/Au Janus particles, in which the hemispherical Au particles are separately attached on the single MoS2 spheres about 100 nm in size. The hemispherical Au particles are built of the ultrafine NPs (<10 nm) and comparable to the MoS2 spheres in size. Further experiments have revealed that the existence of surfactants in the colloidal solution could significantly influence the distribution and decoration of Au NPs on the MoS2 nanospheres. When the MoS2 colloidal solution contains the nonionic or anionic surfactant, such as poly(vinylpyrrolidone) and sodium dodecyl benzene sulfonate, in appropriate content, the addition of HAuCl4 induces the Au ultrafine NPs highly uniformly attached or decorated on the MoS2 spheres. The distribution of the Au ultrafine NPs on the MoS2 spheres evolves from a dispersed decoration to the intact core/shell structure with the rising HAuCl4 addition amount. However, the cationic surfactant could prevent Au NPs from decoration on the MoS2 spheres and induce the self-agglomeration of Au NPs. The formation of MoS2/Au Janus particles is attributed to the aggregation growth of Au ultrafine NPs on the MoS2 spheres, whereas the dispersed decoration of Au ultrafine NPs on the MoS2 spheres is ascribed to the surfactant-induced uniform distribution of Au NPs. Interestingly, such decorated spherical MoS2 NPs have exhibited a much higher surface-enhanced Raman scattering effect than the decorated MoS2 nanoplates. This work presents a simple approach to the controllable decoration of Au NPs on the spherical MoS2 particles.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2018
·Vol. 410
·期 25
·6489-6495
·
IF 3.307
Wen Aoli,Peng Xiaoxiao,Zhang Pingping,Long Yunfei,Gong Huiming,Xie Qingru,Yue Ming,Chen Shu
Berberine hydrochloride (BHC), a natural isoquinoline alkaloid, is widely applied as a an agent in traditional Chinese medicine. Almost all the traditional methods for BHC detection require complicated preprocessing steps or expensive instruments. In this article, we report a simple, rapid, sensitive, and selective method for BHC detection using fluorescent gold nanoclusters (F-AuNCs) as the fluorescent probe with a large Stokes shift of 237 nm. The F-AuNCs prepared with citrate-stabilized stannous chloride and hydrogen tetrachloroaurate(III) as raw materials in an aqueous medium display strong and stable fluorescence at 566 nm. When F-AuNCs are mixed with BHC, the fluorescence of F-AuNCs is effectively quenched. Under optimized conditions, this method allows sensitive and selective measurements of BHC in a concentration ranging from 1.0 × 10 -6 to 1.0 × 10 -4 mol L -1 with a detection limit of 7.5 × 10 -8 mol L -1 , which is relatively low among reported spectral methods. This method provides excellent selectivity for the detection of BHC against inorganic anions and natural amino acids. In addition, the BHC content in two different types of berberine tablets was successfully determined by this method and the results showed high accuracy.
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RSC Advances
·
2016
·Vol. 6
·期 34
·28263-28269
·
IF 3.289
Xiumin Ma,Quantong Jiang,Weimin Guo,Meng Zheng,Weichen Xu,Fubin Ma,Baorong Hou
In this study, a sandwich-structured C3N4/Au/CdZnS photocatalyst with Au nanoparticles sandwiched between C3N4 and CdZnS was fabricated. The results showed that there was a 6.3 mmol g−1 increase of hydrogen production for C3N4/Au/CdZnS photocatalyst compared to C3N4/CdZnS in 4 h. The photoinduced I–t curve, electrochemical impedance spectrum (EIS), photogenerated electron lifetime and photoluminescence spectra showed that the photocatalytic ability of the composite was enhanced by anchoring Au as the electron transfer mediator between C3N4 and CdZnS through the Z-scheme charge-carrier transfer mechanism. Au functioned as an electron transition mediator, which could induce a combination between photogenerated electrons and holes in the CdZnS and C3N4, respectively. These photogenerated holes of CdZnS can be involved in the S2−/SO32− oxidation process and the electrons from the C3N4 surface might be involved in the water to hydrogen reduction reaction, thus enhancing the photocatalysis performance of C3N4/Au/CdZnS photocatalyst.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2015
·
IF 4.097
Wenfeng Zhao,Wei Jia,Mimi Sun,Xiaojun Liu,Qingquan Zhang,Chenghua Zong,Jie Qu,Hongwei Gai
A new simple colorimetric chemosensor for sensitive and selective detection of Cu 2+ using polyethyleneimine (PEI)-capped Au nanoparticles (PEI/Au NPs) has been developed. PEI/Au NPs are synthesized by using PEI as reducer without adding nanoparticles seeds and stabilizing agent. Copper ions are captured by the amino groups of the PEI/Au NPs to form an absorbent complex at the surface of PEI/Au NPs, resulting in the color of PEI/Au NPs changing from wine red to purple. Under the optimal conditions, the proposed colorimetric sensor is capable of sensitively and specifically detecting Cu 2+ with a detection limit of 0.29 μM and a linear range of 25–300 μM. This method is simple, fast and highly selective for Cu 2+ in the presence of high concentrations of other environmentally relevant metal ions because of the great specific coordination between Cu 2+ and PEI, which potentially meets the requirement of the detection in real samples. Moreover, addition of EDTA to PEI/Au NPs-Cu 2+ recovers the color offering PEI/Au NPs as a promising reversible sensor for practical application.
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Precision Chemistry
·
2025
·
IF 6.2
Er-Fei Zhen,Bing-Yu Liu,Meng-Ke Zhang,Lu−Lu Zhang,Chen-Yu Zhang,Jun Cai,Marko M. Melander,Jun Huang,Yan-Xia Chen
Understanding how the electrolyte pH affects electrocatalytic activity is a topic of crucial importance in a large variety of systems. However, unraveling the origin of the pH effects is complicated often by the fact that both the reaction driving forces and reactant concentrations in the electric double layer (EDL) change simultaneously with the pH value. Herein, we employ the hydrogen evolution reaction (HER) at Au(111)-aqueous solution interfaces as a model system to disentangle different pH-dependent factors. In 0.1 M NaOH, the HER current density at Au(111) in the potential range of −0.4 V < ERHE < 0 V is up to 60 times smaller than that in 0.1 M HClO4. A reaction model with proper consideration of the local reaction conditions within the EDL is developed. After correcting for the EDL effects, the rate constant for HER is only weakly pH-dependent. Our analysis unambiguously reveals that the observed pH effects are mainly due to the pH-dependent reorganization free energy, which depends on the electrostatic potential and the local reaction conditions within the EDL. Possible origins of the pH and temperature dependence of the activation energy and the electron transfer coefficients are discussed. This work suggests that factors influencing the intrinsic pH-dependent kinetics are easier to understand after proper corrections of EDL effects.
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Nanomaterials
·
2019
·Vol. 9
·期 7
·932
·
IF 4.034
Dazheng Chen,Gang Fan,Hongxiao Zhang,Long Zhou,Weidong Zhu,He Xi,Hang Dong,Shangzheng Pang,Xiaoning He,Zhenhua Lin,Jincheng Zhang,Chunfu Zhang,Yue Hao
Indium thin oxide (ITO)-free planar perovskite solar cells (PSCs) were fabricated at a low temperature (150 °C) in this work based on the transparent electrode of photolithography processed nickel/gold (Ni/Au) mesh and the high conductivity polymer, PH1000. Ultrathin Au was introduced to increase the conductivity of metal mesh, and the optimal hexagonal Ni (30 nm)/Au (10 nm) mesh (line width of 5 μm) shows a transmittance close to 80% in the visible light region and a sheet resistance lower than 16.9 Ω/sq. The conductive polymer PH1000 not only smooths the raised surface of the metal mesh but also enhances the charge collection ability of metal mesh. The fabricated PSCs have the typical planar structure (glass/Ni-Au mesh/PH1000/PEDOT:PSS/MAyFA1−yPbIxCl3−x/PCBM/BCP/Ag) and the champion PSC (0.09 cm2) obtains a power conversion efficiency (PCE) of 13.88%, negligible current hysteresis, steady current density and PCE outputs, and good process repeatability. Its photovoltaic performance and stability are comparable to the reference PSC based on the ITO electrodes (PCE = 15.70%), which demonstrates that the Ni/Au mesh transparent electrodes are a promising ITO alternative to fabricate efficient PSCs. The relatively lower performance of Ni/Au based PSC results from the relatively slower charge extraction and stronger charge recombination than the ITO based PSC. Further, we tried to fabricate the large area (1 cm2) device and achieve a PCE over 6% with negligible hysteresis and steady current density and PCE outputs. The improvements of perovskite film quality and interface modification should be an effective approach to further enhance the device performance of Ni/Au based PSCs, and the Ni/Au mesh electrode may find wider applications in PSCs and flexible devices.Keywords:metal mesh;transparent electrode;photolithography;perovskite solar cell;large-area solar cell
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