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....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.展开更多
NO adsorption on Ag/Pt（110）-（1×2） bimetallic surfaces at room temperature was investigated by means of Auger electron spectroscopy, X-ray photoelectron spectroscopy and thermal desorption spectroscopy. An une...NO adsorption on Ag/Pt（110）-（1×2） bimetallic surfaces at room temperature was investigated by means of Auger electron spectroscopy, X-ray photoelectron spectroscopy and thermal desorption spectroscopy. An unexpected formation of nitrite/nitrate surface species on Ag/Pt（110）-（1 ×2） bimetallic surfaces is observed, then decompose at elevated temperatures to form N2. However, such nitrite/nitrate surface species do not form on clean Pt（110） and Ag-Pt alloy surfaces upon NO exposure at room temperature. The formation of nitrite/nitrate surface species on Ag/Pt（110）-（1×2） bimetallic surfaces is attributed to high reactivity of highly coordination-unsaturated Ag clusters and the synergetic effect between Ag clusters and Pt substrate.展开更多
采用化学还原法及水热法制备了具有树枝状结构的铂-银气凝胶,并对其进行酸碱刻蚀再处理获得刻蚀后的铂-银气凝胶催化剂.利用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等表征了铂-银气凝胶的结构、组成及微观形貌...采用化学还原法及水热法制备了具有树枝状结构的铂-银气凝胶,并对其进行酸碱刻蚀再处理获得刻蚀后的铂-银气凝胶催化剂.利用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等表征了铂-银气凝胶的结构、组成及微观形貌.利用循环伏安法(CV)和线性扫描伏安法(LSV)测试了催化剂对氧还原反应(ORR)的电催化活性和稳定性.结果表明,刻蚀后的Pt-Ag气凝胶具有优异的ORR活性,在0.9 V处,刻蚀后Pt-Ag气凝胶的质量比活性和面积比活性分别为166.3 m A/mgPt和0.295 m A/cm^2,分别是商业铂/碳催化剂(20%Pt/C)的2.0倍和1.8倍.该催化剂还具有优异的稳定性,循环5000周后,动力学催化质量比活性和面积比活性分别只降低了6.1%和9.1%,远小于商业Pt/C的35%和52.1%.展开更多
Ag-Pt bimetallic nanoparticles decorated on MWCNTs/PANI nanocomposites have been synthesized by in-situ chemical oxidative polymerization and chemical co-reduction method. The Fourier transform infrared（FT-IR） spect...Ag-Pt bimetallic nanoparticles decorated on MWCNTs/PANI nanocomposites have been synthesized by in-situ chemical oxidative polymerization and chemical co-reduction method. The Fourier transform infrared（FT-IR） spectroscopy, X-ray diffraction（XRD）, ultraviolet-visible（UV-vis） absorption spectroscopy, scanning electron microscopy（SEM） and transmission electron microscopy（TEM） were used to characterize the morphology and structure of the nanocomposites. It can be observed that the PANI was uniformly grown along the MWCNTs to form MWCNsT/PANI fiber-like nanocomposites with diameter about 60 nm, and the Ag-Pt binary nanoparticles were decorated onto MWCNTs/PANI with particle sizes around 6.8 nm. Cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS） were used to characterize the electrochemical performance of the prepared electrode. The results demonstrated that the obtained MWCNTs/PANI/Ag-Pt electrode displayed a good electrochemical activity and fast electron transport, which has potential applications in biosensors and supercapacitors.展开更多
基金support of the National Natural Science Foundation of China (Nos. 21375017, 21105012 and 21205015)the National Science Foundation for Distinguished Young Scholars of Fujian Province (No. 2013J06003)+3 种基金the Key Project of Fujian Science and Technology (No. 2013Y0045)the Program for New Century Excellent Talents of Colleges and Universities in Fujian Province (Nos. JA13130 and JA13088)the Program for Fujian University Outstanding Youth Scientific Research (Nos. JA11105 and JA10295)the Foundation of Fuzhou Science and Technology Bureau (No. 2013-S-122-4)
文摘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.
基金This work was supported by the National Natural Science Foundation of China （No.20973161 and No.11079033）, the Ministry of Science and Technology of China （No.2010CB923302）, the Fundamental Research Funds for the Central Universities, and the MPG-CAS partner group program.
文摘NO adsorption on Ag/Pt（110）-（1×2） bimetallic surfaces at room temperature was investigated by means of Auger electron spectroscopy, X-ray photoelectron spectroscopy and thermal desorption spectroscopy. An unexpected formation of nitrite/nitrate surface species on Ag/Pt（110）-（1 ×2） bimetallic surfaces is observed, then decompose at elevated temperatures to form N2. However, such nitrite/nitrate surface species do not form on clean Pt（110） and Ag-Pt alloy surfaces upon NO exposure at room temperature. The formation of nitrite/nitrate surface species on Ag/Pt（110）-（1×2） bimetallic surfaces is attributed to high reactivity of highly coordination-unsaturated Ag clusters and the synergetic effect between Ag clusters and Pt substrate.
文摘采用化学还原法及水热法制备了具有树枝状结构的铂-银气凝胶,并对其进行酸碱刻蚀再处理获得刻蚀后的铂-银气凝胶催化剂.利用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等表征了铂-银气凝胶的结构、组成及微观形貌.利用循环伏安法(CV)和线性扫描伏安法(LSV)测试了催化剂对氧还原反应(ORR)的电催化活性和稳定性.结果表明,刻蚀后的Pt-Ag气凝胶具有优异的ORR活性,在0.9 V处,刻蚀后Pt-Ag气凝胶的质量比活性和面积比活性分别为166.3 m A/mgPt和0.295 m A/cm^2,分别是商业铂/碳催化剂(20%Pt/C)的2.0倍和1.8倍.该催化剂还具有优异的稳定性,循环5000周后,动力学催化质量比活性和面积比活性分别只降低了6.1%和9.1%,远小于商业Pt/C的35%和52.1%.
基金Funded by National Natural Science Foundation of China(Nos.51371129 and 11174226)Hubei Science and Technology Supported Project(No.YJG0261)+1 种基金Wuhan Science and Technology Research Project(No.2014010101010002)the Key Project of Guangdong Province(No.2013B090500078)
文摘Ag-Pt bimetallic nanoparticles decorated on MWCNTs/PANI nanocomposites have been synthesized by in-situ chemical oxidative polymerization and chemical co-reduction method. The Fourier transform infrared（FT-IR） spectroscopy, X-ray diffraction（XRD）, ultraviolet-visible（UV-vis） absorption spectroscopy, scanning electron microscopy（SEM） and transmission electron microscopy（TEM） were used to characterize the morphology and structure of the nanocomposites. It can be observed that the PANI was uniformly grown along the MWCNTs to form MWCNsT/PANI fiber-like nanocomposites with diameter about 60 nm, and the Ag-Pt binary nanoparticles were decorated onto MWCNTs/PANI with particle sizes around 6.8 nm. Cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS） were used to characterize the electrochemical performance of the prepared electrode. The results demonstrated that the obtained MWCNTs/PANI/Ag-Pt electrode displayed a good electrochemical activity and fast electron transport, which has potential applications in biosensors and supercapacitors.
