Nanoscale
·
2023
·
IF 6.7
Xin Huang,Haitao Li,Bin Zhang,Yin Zhang,Hao Wang,Lijun Ban,Yixuan Xu,Yongxiang Zhao
It has been widely recognized that adjusting the size of Au particles has emerged as a significant approach in catalyst design, catalyst screening, and comprehension of reaction mechanisms. However, the essential factors of Au nanoparticles used only as an additive to enhance the activity of traditional multicomponent thermocatalysts have not been fully revealed. In this study, a series of Au@Cu2O core–shell nanocatalysts were synthesized through a controllable method, featuring core sizes ranging from 11 to 33 nm and an average shell thickness of approximately 55 nm. It was revealed that the size effect of Au cores plays a very vital role in the stability of the active Cu+ species under reducing atmospheres (H2, acetylene and formaldehyde) as well as the catalytic performance of the catalysts in the ethynylation of formaldehyde. The experimental findings revealed that Au@Cu2O core–shell catalysts with Au core sizes ranging from 11 to 16 nm exhibited a higher abundance of electron-deficient Cu+ species in the shell, which is attributed to the strong long-range electromagnetic effects of the Au core in the absence of photoexcitation or an applied electric field. Additionally, the active Cu+ species demonstrated remarkable stability under reducing atmospheres. Although the stability of Cu+ decreased slightly when the Au core size exceeded 16 nm, the Cu+ content remained above 80%. Notably, the Au@Cu2O catalysts with Au core sizes ranging from 11 to 16 nm exhibited excellent catalytic activity in the ethynylation of formaldehyde.
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Journal of Cleaner Production
·
2023
·
IF 11.1
Dongping Song,Tao Huang,Yinglan Luo,Di Wu,Shouze Li,Yujie Yan,Chaojun Yang,Qi Fang,Yuxing Wang,Yuxuan Feng,Nan Shang,Ming Xia,Haiyan Li
Thallium(I) (Tl(I)) is a highly toxic substance with significant environmental toxicity, belonging to the high-toxicity category, with characteristics of chronic accumulation. In this study, cerium(IV) (Ce(IV)) was incorporated into nonthermal plasma (NTP)-irradiated polyvalent manganese (hydro)oxides and synchronously grafted onto nanographene to synthesize a new type of Mn-based adsorbent (NTP-P-Ce-Mn-NGs) with excellent adsorption capacities for Tl(I) contaminants, aiming to overcome the weak adsorption capacity of existing adsorbents for Tl(I) and propose a new approach to enhance their adsorption performance. The factors including the molar ratios of Ce(SO 4 ) 2 to MnCl 2 , the dosage of nanographene, and the irradiation time of NTP all significantly affected the synthesis of NTP-P-Ce-Mn-NGs. Both the participation of NTP and the intercalation of Ce(IV) exerted a potential influence on the adsorption improvement of Mn-based adsorbents towards Tl(l) contaminants. Different chemical valences of Ce and Mn species were observed in the synthesized adsorbent. More flocculated and amorphous fillings were generated in the adsorbent samples with both Mn and Ce, visually presenting the incorporation effect of Ce into the NTP-irradiated Mn (oxy)hydroxides. A maximum adsorption capacity of 352.18 mg/g was obtained by NTP-P-Ce-Mn-NGs at an initial pH of 11, an initial concentration of Tl(I) of 250 mg/L, and a dosage of adsorbent of 0.15 g/L. The kinetics models, including the pseudofirst-order , pseudonth-order , mixed 1,2-order , and hyperbolic tangent Ⅱ models, were all appropriate for analysing the heterogeneous adsorption process of NTP-P-Ce-Mn-NG towards Tl(I) ions under different pH conditions. The excessive OH − ions in the alkaline environment intensified the adsorption of Tl(I) ions onto the active sites of NTP-P-Ce-Mn-NGs and further strengthened the relevant chemical reactions in which the polyvalent Mn and Ce further oxidized Tl species from Tl(I) to Tl(III), induced internal dispersion of Tl ions by the nanographene into the molecular structure and achieved chemical immobilization.
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FOOD CHEMISTRY
·
2021
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IF 7.514
Yuncong Xu,Ling Zhao,Ling Chen,Yali Du,Yuanyuan Lu,Chen Luo,Yijun Chen,Xuri Wu
A new compound, α-siamenoside I (α-SI), with a glucose unit selectively bound to the 6-hydroxyl group of the 24- O -β-glucosyl moiety of mogroside IIIE by α-1,6-glucosidic bond, was bio-created by two screened cyclodextrin glycosyltransferases with a maximum yield of 59.3%. Compared to mogroside IIIE, α-SI showed a significantly increased sweetness intensity (508 times sweeter than 5% sucrose), which is superior to siamenoside I (SI), the sweetest triterpenoid saponin isolated from Siraitia grosvenorii to date. Sensory evaluation showed that the taste quality of α-SI also was obviously better than mogroside IIIE. In addition to α-SI possessing a good stability similar to that of SI, it also did not cause a significant decrease in cell viability at a concentration of 200 μg/mL and had a negative influence on islets function at 1 μM. All of these preliminarily results pave the way for promoting α-SI as a potential low-calorie sweetener.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 11
·1-10
·
IF 6.232
Ye Jianping,Cai Xin,Zhou Qing,Yan Zhihong,Li Kang
A molecularly imprinted ratiometric fluorescent probe (MIRF probe) was synthesized for the determination of aristolochic acid I (AAI) based on the Schiff-base fluorescent compound N,N′-bis(o-carboxybenzylidene)-p-4,4′-diaminobiphenyl (BDDB). The BDDB was immobilized in the silica nanoparticle (BDDB@SiO 2 ) as an internal standard material. The blue-emitting BDDB@SiO 2 and the yellow-emitting carbon quantum dots (y-CDs) were wrapped in the molecularly imprinted polymer (MIP) to provide a reliable reference signal at 440 nm and a fluorescent response signal at 530 nm at the excitation wavelength of 365 nm, respectively. In the preparation of the MIP of the MIRF probe, 4-vinylbenzoic acid as the functional monomer and AAI as the template molecule were used. An imprinting factor of 2.25 was obtained. Under the optimum conditions, the fluorescent response signal at 530 nm was quenched gradually by AAI in the range 1.0 to 120.0 μmol/L, while the reference signal at 440 nm remained unchanged. The limit of detection was 0.45 μmol/L, and the fluorescent color of the MIRF probe changed gradually from yellow to green to blue, which illustrated that the developed probe had a specific AAI recognition ability, a good anti-interference ability, and a sensitively visual determination ability. The probe was successfully applied to the AAI determination in traditional Chinese medicine (TCM) Asarum . The results showed that it had satisfactory recoveries (95.5–107.3%) and low relative standard deviations (2.0%). Furthermore, this method has a potential for the onsite naked eye determination of AAI in TCM samples. Graphical abstract
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ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Lu Shi,Feifei Cao,Limin Zhang,Yang Tian
The development of switches responding to specific pH changes was particularly useful in wide application fields. Owing to flexible switches simulated by pH, i-motif DNAs are widely used as a pH sensor. But its character of structure transition strongly dependent on acidic pH severely hampers the application of i-motif DNA in physiological media. Herein, we report the stable i-motif structure formed at a physiological pH triggered by spatial confinement of silica nanochannels. Three classic DNA chains containing 21-mer i-motif domain base-pairs and a single-stranded multiply (T)n spacer, 5′-COOH-(T)n-CCCTAACCCTAACCCTAACCC-3′, were employed to evaluate the enhanced stability of i-motif structure. Compared to their free states in a dilute solution, the transition pH of all i-motif DNAs decorated in nanochannels remarkably shifts toward a neutral pH. Moreover, the transition midpoint can be tuned sensitively over the physiologically relevant pH range through slightly varying the length of T base spacer. Density functional theory (DFT) calculations validate that the increased proton density in a nanochannel triggers the formation of an i-motif structure under a neutral pH. Finally, this i-motif DNA based nanochannels electrode was successfully employed to monitor pH in brain microdialysates followed by cerebral ischemia. The present approach is not limited by fundamental investigation for DNA conformation but may extend toward the manipulation of i-motif based structures for artificial molecular machines and signaling systems.
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JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Qi Liang,Xiaoying Fu,Jianfeng Zhang,Jiaxue Hao,Gangjun Feng,Jing Wang,Qian Li,Faizan Ahmad,Xinfeng Zhao
The enormous growth in drug discovery paradigm has necessitated continuous exploration of new methods for drug-protein interaction analysis. To enhance the role of these methodologies in designing rational drugs, this work extended an immobilized angiotensin II type I receptor (AT 1 R) based affinity chromatography in antihypertensive compound identification. We fused haloalkane dehalogenase at C-terminus of AT 1 R and expressed the fusion receptor in E. coli. The expressed receptor was covalently immobilized onto 8.0 μm microspheres by mixing the cell lysate with 6-chlorocaproic acid-modified amino polystyrene microspheres. The immobilized AT 1 R was utilized for thermodynamic and kinetic interaction analysis between the receptor and four specific ligands. Following confirmation of these interactions by molecular docking, we identified puerarin and rosmarinic acid by determining their binding to the receptor. Azilsartan, candesartan, valsartan and olmesartan displayed two kinds of binding sites to AT 1 R by injection amount-dependent method. By molecular docking, we recognize the driving forces of the interaction as electrostatic interaction, hydrogen bonds and van der Waals force. The dissociation rate constants (k d ) of azilsartan, candesartan, valsartan and olmesartan to AT 1 R were 0.01138 ± 0.003, 0.05142 ± 0.003, 0.07547 ± 0.004 and 0.01310 ± 0.005 min −1 by peak profiling assay. Comparing with these parameters, puerarin and rosmarinic acid presented lower affinity (K A : 0.12 × 10 4 and 1.5 × 10 4 /M) and slower kinetics (k d : 0.6864 ± 0.03 and 0.3005 ± 0.01 min −1 ) to the receptor. These results, taking together, indicated that the immobilized AT 1 R has the capacity to probe antihypertensive compounds.
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JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Siqi Zhuo,Yan Liu,Wei Li,Zhi Ding,Mingda Li,Qianjin Li,Xin Wang,Jie Liu,Rui Shao,Qianqian Ling,Tiesong Zheng,Jianlin Li
Ordered porous materials are attracting enormous attention due to their uniform pore structures, particularly the magnetic photonic crystal microspheres (PCMs) which not only possess unique photonic crystal structure but also can achieve separation easily based on magnet. Here, a two-phase microfluidic self-assembly synthetic system was established simply and employed for the preparation of three dimensional PCMs (3DPCMs) by using the emulsion droplet approach. One phase (dispersed phase) was an aqueous emulsion containing Fe 3 O 4 , silica (SiO 2 ) and polystyrene (PS) nanoparticles; another phase (continuous phase) was pure silicone oil. The droplets were formed by introducing the dispersed phase into the continuous phase through a tee valve. By heating the droplets, the water would evaporate and the nanoparticles would finally assemble into solid microspheres, which could be changed into macroporous 3DPCMs after removal of the PS nanoparticles by calcination. The contents and particle sizes of Fe 3 O 4 , SiO 2 and PS nanoparticles in the dispersed phase were investigated in detail and optimized to prepare macroporous magnetic 3DPCMs with high quality. The morphologies, surface crystal structure, magnetic property, particle size distribution, specific surface area and pore size of the macroporous magnetic 3DPCMs were characterized. The expected 3DPCM displayed regular and uniform photonic crystal structure, narrow particle size distribution and strong magnetic property. The macroporous magnetic 3DPCMs grafted with vomitoxin (DON)-antibodies could be applied for selective enrichment of DON in real samples.
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JOURNAL OF SEPARATION SCIENCE
·
2021
·Vol. 44
·期 17
·3279-3286
·
IF 3.645
Youqing Sun,Yugao Guo,Jianpo Ren,Lieyi Ji,Qingyin Zhang
By replacing the permanent magnet with an electromagnet, traditional magnetic solid-phase extraction was developed into electromagnetic dispersive solid-phase extraction. A simple operation of power on and off can realize the separation of adsorbents from solutions easily. The improvement makes it possible for the automation of the determination of Sudan Red I by high-performance liquid chromatography. After series of optimization, a trace amount of Sudan red I was well-determined, and excellent linearity was achieved in the range of 0.005 to 1 mg/L with the correlation coefficient ( R 2 ) = 0.997. The limit of detection with a signal-to-noise ratio of 3 was found to be 0.001 mg/L. The spiked recoveries of Sudan red I for the samples ranged from 93.6 to 104.9%. Moreover, the adsorbent could be recycled at least ten times. The results show that the electromagnetic dispersive solid-phase extraction combined with high-performance liquid chromatography is a rapid, eco-friendly, effective, and sensitive determination method with fascinating automation potential and high practical applicability.
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CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Jianjun Wang,Wenheng Li,Zihan Zhou,Zhiyong Gao,Yuehua Hu,Wei Sun
Fluorite is usually separated from calcite by froth flotation method using large amounts of sodium silicate depressant, which can cause trouble in the loss of fluorite and wastewater treatment. In this study, green and low-cost 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP or H 4 L) was used as pH-dependent switch to initially depress fluorite for calcite pre-removal at pH 6.0, and then activate fluorite for further upgrading fluorite concentrate at pH 8.0. The depressing behavior and mechanism were reported in this work. H 2 L 2− was the dominant form of HEDP, and a stronger chemical adsorption of H 2 L 2− on fluorite hindered the subsequent adsorption of sodium oleate (NaOL), while that of the calcite showed the opposite result. Two active O atoms in H 2 L 2− could well match in interatom distance with two Ca sites on fluorite to form Ca-H 2 L complexes. The pH-dependent switch reagent reported here may open a new avenue for more selective separation among mixed mineral systems.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Chunpeng Bai,Jingce Bi,Junbiao Wu,Yan Xu,Sebastian Wohlrab,Yide Han,Xia Zhang
In this work, a series of Ag/AgX (X = Cl, Br, I)/g-C 3 N 4 (Ag/AgX/CN) composites were successfully fabricated by an in-situ solid phase method. The morphology and structure, photoluminescence and photoelectrochemical properties of composites were investigated in detail. The as-prepared Ag/AgX/CN composites were used as H 2 evolution photocatalysts under visible-light irradiation with a sacrificial agent . The experimental results revealed that Ag/AgI/CN-4 composite possesses highest-H 2 evolution rate (up to 59.22 μmol g −1 h −1 ) which are approximately 31 times higher than that of pure g-C 3 N 4 (1.94 μmol g −1 h −1 ). In addition, Ag/AgCl/CN-4 and Ag/AgBr/CN-4 composites also present high photocatalytic activities yielding, 26.39 and 18.05 μmol H2 g −1 h −1 , respectively. The enhanced photocatalytic activities of Ag/AgI/CN-4 composite might be attributed to the synergistic effect between Ag/AgI nanoparticles and g-C 3 N 4 and the localized surface plasmon resonance effect of metallic Ag. Moreover, Ag/AgI/CN-4 composite showed excellent recyclability and stability after five cycling photocatalytic tests (about 25 h). Furthermore, the possible photocatalytic mechanism of Ag/AgI/CN composites is proposed.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-8
·
IF 5.479
Liu Jianbo,Shang Yonghui,Zhu Qiuyan,Zhang Xinxue,Zheng Jianbin
A voltammetric immunoassay for the carcinoembryonic antigen (CEA) was developed using silver metal-organic frameworks (Ag-MOFs) as a signal probe. The Ag-MOFs contained a substantial amount of Ag(I) whose electrochemical signal was relatively stable. Therefore, the Ag-MOFs were viable signal probes. The signal can be detected without previous acid dissolution and preconcentration steps. This simplifies the detection steps and reduces the detection time. If CEA binds to its antibody on the modified electrode, the signal for Ag(I) becomes reduced. Measurements were best performed at a potential as low as 0.07 V (vs. SCE) which made the electrode hardly sensitive to potential electroactive interferents. Under optimized conditions, the method included a wide linear response range (0.05 to 120 ng mL −1 ) and a low detection limit of 8.0 fg mL −1 (S/ N = 3). The synthesis of Ag-MOFs is relatively simple, and Ag-MOFs are not only used as nanocarriers for immobilizing anti-CEA but also acted as electroactive materials for a signal probe. The voltammetric immunoassay is stable, inexpensive, sensitive, and selective. Based on these advantages, the method holds great promise for applications in the point-of-care disease and environmental monitoring.
Schematic presentation of a novel electrochemical immunoassay for the carcinoembryonic antigen (CEA) using silver metal-organic frameworks (Ag-MOFs) as a signal probe.
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JOURNAL OF COORDINATION CHEMISTRY
·
2018
·
IF 1.703
Jiajia Lai,Xianying Duan,Hui Yang,Meilin Wei
Two proton-conductive Cu(I) complexes based on Keggin-type clusters, [Cu(debqdc)2]2[HPW12O40]·4H2O (1), and [Cu(debqdc)2]2[HPW12O40]·debqdc·4H2O (2), where debqdc is diethyl 4,4′-dicarboxy-2,2′-biquinoline, were simply synthesized at room temperature. The products were structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses revealed that both complexes crystallized in the triclinic space group P−1 and presented two three-dimensional supramolecular networks with one-dimensional hydrophilic channels via hydrogen-bonding interactions and π–π stacking interactions between the aromatic rings. In the [Cu(debqdc)2]+ ion, debqdc acts as a bidentate nitrogen donor ligand in the chelating fashion. The bulky debqdc ligand constrains the Cu(I) metal center within such a rigid environment in a tetrahedral geometry. The two complexes exhibit good proton conductivities (10−5 ~ 10−4 S cm−1) at 100 °C in the relative humidity range 35 ~ 98%. The luminescence behaviors of these complexes in the solid state at room temperature have also been investigated. Upon excitation at 285 nm, both 1 and 2 display three main emission peaks centered at 470, 520, and 568 nm, respectively.
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