Protein Templated Au-CuO Bimetallic Nanoclusters toward Neutral Glucose Sensing

In this study,the application of bovine serum albumin(BSA)as a carrier to glucose-sensitive materials for the detection of glucose was proposed.Au-Cu O bimetallic nanoclusters(Au-Cu O/BSA)were prepared using BSA as a template,the new sensing material(Au-Cu O/BSA/MWCNTs)was synthesized by mixing with multi-walled carbon nanotubes(MWCNT)and applied to non-enzymatic electrochemical sensors to detect glucose stably and effectively under neutral condition.The scanning electron microscopy was used to investigate the morphology of the synthesized nanocomposite.The electrochemical properties of the sensor were studied by cyclic voltammetry.Glucose detection experiments show that Au-Cu O/BSA/MWCNTs/Au electrode has good glucose detection ability,stability,accuracy,repeatability,and high selectivity in neutral environment.Unlike existing glucose-sensitive materials,due to the use of BSA,the composite material is firmly fixed to the electrode surface without a Nafion solution,which reduces the current blocking effect on the modified electrode.The composite materials can be effectively preserved for extremely long periods,higher than 80%activity is maintained at room temperature in a closed environment for 3 to 4 months,due to the special effects of BSA.In addition,the feasibility of using BSA in glucose-sensitive materials is confirmed.

An examination of active sites on Au-Ag bimetallic catalysts based on CO oxidation over Au/Ag_2O and a comparison to Ag-contaminated Au powder

There are two theories regarding the origin of the remarkable synergistic effect observed in Au‐Ag bimetallic catalysts when applied to various oxidative reactions. One is based on the importance of the contact interfaces between AgOx regions and the surface of the bulk Au as active working sites, while the other holds that charge transfer from Ag to Au in a surface Au‐Ag alloy causes the catalytic activity. One key point in examining these theories and determining the origin of the synergy in‐volves determining whether or not Ag exists as an oxide or as a metallic alloy on the Au surface. To confirm that enhanced activity results from contact between Ag2O and Au nanoparticles （NPs）, a comparative study of catalytic CO oxidation over Au/Ag2O and Ag2O was performed in the present work, using a closed recirculation reaction system. A reaction mixture consisting of a stoichiometric composition of CO and O2 （CO/O2=2/1） was supplied to both catalysts and the resulting pressure decrease rates were tracked, from which the amounts of gas consumed as well as the quantity of CO2 produced were determined. The steady state reactions of both Au/Ag2O and Ag2O did not lead to any meaningful difference in the rate of pressure decrease during the oxidation. The pressure decrease over both catalysts was attributed to the reduction of surface lattice O on Ag2O by CO. The results obtained for Au/Ag2O are in good agreement with previous data resulting from the use of Ag‐contaminated Au powder （Ag/Au‐b） having an oxidized surfaces. This finding suggests that the perimeters between AgOx zones and the bulk Au surface may not function as active sites during CO oxidation. A review of previous results obtained with Ag/Au‐b specimens having so‐called steady state surfaces indicates that AgOx species in such materials are reduced to the 0 state to form a Ag‐Au alloy that provides the active sites.

Donor-acceptor covalent organic frameworks-confined ultrafine bimetallic Pt-based nanoclusters for enhanced photocatalytic H_(2)generation

Photocatalytic hydrogen generation from hydrogen storage media is an effective and promising approach for the green hydrogen industry as well as for achieving carbon neutrality goals.However,the lower photocatalytic efficiency due to the limited light trapping capacity,low electron transfer rate,and severe aggregation of nanoparticles caused by high surface energy seriously restricts their practical application.Herein,we constructed a series of donor–acceptor(D–A)type covalent organic frameworks to confine ultrafine bimetallic Pt-based nanoclusters for photocatalytic hydrogen generation from ammonia borane(AB)hydrolysis.Under visible light irradiation at 20℃,PtCo_(2)@covalent organic framework(COF)showed the highest photocatalytic activity with a turnover frequency(TOF)of 486 min−1.Experiments and density functional theory(DFT)calculations reveal that the high catalytic activity is mainly attributed to the strong electronic interactions between D–A type COF and ultrafine PtCo_(2)nanoclusters.Specifically,the D–A type COF can significantly enhance the light-trapping ability by fine-tuning the electron-acceptor type in the framework,and accelerate the photogenerated electron transfer from D–A type COF to PtCo_(2)nanocluster,which promotes the adsorption and activation of H_(2)O and AB molecules and accelerates hydrogen release.Furthermore,PtCo_(2)@COF also exhibited ultra-high durability due to the significantly enhanced resistance to nanocluster aggregation caused by the nanopore confinement effect of D–A type COF.We believe that this work will provide a theoretical guide for the rational design of efficient D–A COFbased catalysts for photocatalysis.

Electrochemical aptasensor for the detection of vascular endothelial growth factor(VEGF) based on DNA-templated Ag/Pt bimetallic nanoclusters

In this paper, the DNA-templated Ag/Pt bimetallic nanoclusters were successfully synthesized using an optimized synthetic scheme. The obtained DNA-Ag/Pt NCs have an ultrasmall particle size and excellent distribution. The DNA-Ag/Pt NCs show intrinsic peroxidase-mimicking activity and can effectively catalyze the H2O2-mediated oxidation of a substrate, 3,30,5,50-tetramethylbenzidine（TMB）, to produce a blue colored product. Based on this specific property, we employed the aptamer of VEGF to design a label-free electrochemical biosensor for VEGF detection. Under the optimized experimental conditions, a linear range from 6.0 pmol/L to 20 pmol/L was obtained with a detection limit of 4.6 pmol/L. The proposed biosensor demonstrated its high specificity for VEGF and could directly detect the VEGF concentration in human serum samples of breast cancer patients with satisfactory results. This novel electrochemical aptasensor was simple and convenient to use and was cost-effective and label-free in design, and would hold potential applications in medical diagnosis and treatment.

Atomically precise coreless AuCu bimetallic nanoclusters for Ullmann C-O coupling

Bimetallic nanocluster with atomic precision has gained widespread attention due to its unique synergism.The coreless Au_(4)Cu_(5)bimetallic nanoclusters were selected as models to explore the relationship between their microstructure and performance,and compare with the coreless monometallic nanoclusters,core–shell nanoclusters,and single atom catalyst(SAC).The experimental results show that the coreless bimetallic nanocluster catalyst Au_(4)Cu_(5)/activated carbon(AC)exhibits high activity and stability in the Ullmann C–O coupling reaction,much higher than coreless monometallic nanoclusters(Au_(11)/AC and Cu_(11)/AC),core–shell nanoclusters(Au_(25)/AC,Cu_(25)/AC,and Au_(1)Cu_(24)/AC),and single atom catalysts(Au SAC and Cu SAC).Moreover,the coreless Au_(4)Cu_(5)/AC catalyst efficiently catalyzed the Ullmann C–O coupling of benzyl alcohol for the first time.This structure–activity relationship was successfully extended to other coreless bimetallic systems,such as Au_(4)Cu_(4)/AC nanocluster,and it is expected to provide new insights for the design of bimetallic catalysts with well-defined performance.

Ni_(4)-thiacalix[4]arene sandwiched Mo_8 polyoxometalate bimetallic nanoclusters for electrocatalytic glucose oxidation

Available online two new Ni_(8)Mo_(8) bimetallic coordination clusters,[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(PO_(4))](+Solvent)(Ni_(8)PMo_(8),H_(4)TC4A=p-tert-butylthiacalix[4]arene) and[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(OH)(CO_(3))](+Solvent)(Ni_(8)Mo_(8)),were synthesized by solvothermal method and structurally characterized by single-crystal X-ray diffraction,powder X-ray diffraction,FT-IR spectroscopy,and TGA experiments,respectively.The usage of H_(3)PMo_(12)O_(40) as source for Ni_(8)PMo_(8) resulted a sandwich like structure built from two Ni_(4)-thiacalix[4]arene units and a Mo_(8) polyoxometalate with inner spaces of PO_(4)^(3-).Ni_(8)Mo_(8) with the similar structure to that of Ni_(8)PMo_(8) is from H_(2)MoO_(4) starting reagent with OH^(-)and CO_(3)^(2-)anions encapsulated in the center.The two clusters can be directly loaded on carbon paper and utilized as working electrodes which showed distinguishable performances for glucose detection and oxidation.This work provides a better understanding of the structure-property relationships in using substituted polyoxometalates for electrochemical applications and is helpful for building calixarene-based or polyoxometalatebased functional materials.

基于DNA银铂双金属纳米簇的电化学传感器用于Hg^(2+)的检测

以DNA为模板,通过一步法合成了一种银铂双金属纳米簇(DNA-Ag/Pt NCs),其粒径为2~4 nm,并表现出较强的过氧化物模拟酶活性,能催化H2O2氧化TMB使溶液变蓝色。基于此特性,结合Hg2+可与胸腺嘧啶碱基形成T-Hg2+-T结构,设计研制了一种非标记的电化学传感器,用于Hg2+的灵敏特异性检测。实验结果表明,在最佳条件下,该传感器的检测范围为0.65~3.5 nmol/L,检出限达0.17 nmol/L,能较好地识别Hg2+。该传感器有望用于实际水样中痕量汞的检测。

金-银双金属纳米簇@多壁碳纳米管-二氧化钛纳米材料为新型氧化还原探针构建电化学免疫传感器

该研究合成了具有独特“珍珠项链”结构的金-银双金属纳米簇@多壁碳纳米管-二氧化钛纳米复合材料(Au-Ag NCs@CNTs-TiO_(2)NPs)作为信号标签、载体和信号放大器,构建了一种高灵敏“三明治”式电化学免疫传感器用于糖类抗原19-9(CA19-9)的检测。首先将具有过氧化物模拟酶特性的磁性Au-Fe_(3)O_(4)NPs用于修饰电极,然后通过化学键合作用将anti-CA19-9抗体和BSA固载于电极表面,再通过特异性反应结合不同浓度的抗原和具有氧化还原活性和放大作用的Au-Ag NCs@CNTs-TiO_(2)NPs/Ab_(2)/BSA生物耦合物形成夹心免疫结构进行检测。结果表明,通过双重过氧化物模拟酶催化底液中的H_(2)O_(2),有效地放大了响应信号,在最优条件下,CA19-9在0.01~200 U/mL浓度范围内线性关系良好,最低检出限为0.003 U/mL。采用标准加入法测得免疫传感器的回收率为94.6%~105%,相对标准偏差(RSD)为4.3%~6.5%,表明该免疫传感器有望用于临床血清样品中CA19-9的检测。

铜纳米粒子负载于钴纳米片的双金属催化剂催化CO选择性加氢(英文)

使用赖氨酸作为表面活性剂模板,合成了Cu纳米粒子负载于Co纳米片的双金属催化剂Cu/Co.与常规的Cu-Co双金属纳米颗粒催化剂相比,Cu/Co催化剂对CO选择性加氢反应表现出特殊的结构效应,提高了CO转化率和高级醇选择性,降低了甲烷选择性.Cu/Co催化剂中,Cu(111)面与Co(100)面相互作用的功能化界面有利于深入研究金属-金属的相互作用.这种双金属催化剂可以将模型催化剂和现实催化应用联系起来,将有助于获得对合成气转化制高级醇反应机理的本质认识.

高荧光强度金银合金簇的合成及其对Hg2+的检测

本研究以牛血清白蛋白(BSA)作为模板,合成了一种荧光强度高、水溶性好、稳定性好的金银合金簇。由于Hg2+与金银合金簇表面的Au+之间存在的高亲和性的Hg2+-Au+噬金属效应,Hg2+的存在能导致金银合金簇的荧光信号显著降低。根据此原理,本文构建了一种基于金银合金簇的Hg2+的荧光传感检测方法。该方法对Hg2+检测的线性范围为2.0×10-9~3.0×10-8 mol/L,检测限达到6.0×10-10 mol/L,同时实现对闽江水中痕量Hg2+的测定。

基于金银双金属纳米簇的荧光传感方法研究进展

金属纳米簇(Metal NCs)是一种发展迅速的纳米材料,核心尺寸小于2 nm的贵金属纳米颗粒现已被认为是金属纳米簇。与由单金属原子组成的纳米团簇相比,双金属纳米簇通过协同效应掺入外来原子的其他性质把两种贵金属的优异性能结合在一起,往往表现出更加优异的光学、电子和催化特性,在离子检测、生物小分子检测及生物分析方面具有广阔的应用前景。在这篇综述中,从性能、合成策略及应用三方面对基于金银双金属纳米簇的荧光传感系统的研究进行总结,并对未来的发展方向进行展望。

Investigation of Charge Transport in Percolating Network of PdCu Nanoclusters

Transport of charge carriers in percolating nanocluster devices based on bimetallic PdCu nanoclusters was investigated in this work. The device was fabricated by self-assembly of the nanoclusters between electrical electrodes inside an ultra-high vacuum compatible system. The average size of the produced nanoclusters was 7.3 nm, and the composition was Pdo.77Cuo.23. Systematic in situ current-voltage measurements as a function of temperature were per- formed which provide a conductance-temperature profile. The results are explained in terms of the charge carriers＇ tunneling through small potential barriers at the junctions between nanoclusters. The results predict the size of the nanoclusters as well as the magnitude of the potential difference of the tunneling barriers. This investigation helps understanding the nature of the interface between the nanoclusters and the charge carrier transport within those devices to be utilized for optimizing gas sensing properties of PdCu nanocluster devices.

基于DNA-Ag/Pt双金属纳米簇比色法检测葡萄糖

葡萄糖是血糖含量的指标。在人体血糖含量上升的过程中,通常伴随着人体某些疾病的产生,比如高血压、高血脂、眼疾等。因此,快速、简便、灵敏的定量检测葡萄糖对临床分析与诊断具有重要意义。研究发现,以DNA为模板合成的银铂双金属纳米簇具有过氧化物模拟酶活性,其催化能力强弱在一定范围内依赖于H 2 O 2的浓度。基于此特性,文章构建了一种比色传感器用于葡萄糖的检测。实验结果表明,在最佳条件下,该比色传感器对葡萄糖的检测范围为400~900μmol/L,检测限为200μmol/L,且传感器对葡萄糖的检测具有高选择性,并可应用于实际血清样品中葡萄糖的检测。该比色传感器成本低、操作简便、灵敏度高、选择性好,具有潜在的应用价值。

二氧化碳氢化制多碳化合物金属纳米簇催化

二氧化碳催化氢化合成多碳化合物的研究对于减少碳排放和实现碳资源的可再生利用具有重要意义。本文总结概述了近年来二氧化碳氢化合成多碳化合物催化体系研究进展,着重介绍了低温下催化CO_(2)氢化合成多碳烃或多碳醇的金属纳米簇基催化剂的研究进展,讨论了CO_(2)氢化反应中C1和C_(2+)产物选择性调控的化学基础,介绍了具有低温催化CO_(2)氢化合成多碳化合物功能和高C_(2+)化合物选择性的PtRu双金属纳米簇催化剂的合成和构-效关系研究进展。在此基础上,进一步阐述了所提出的金属纳米簇催化剂局域电荷分布效应理论。