Pd was electrochemically deposited on gold-coated quartz crystals at nanogram-level. The coulombic efficiency and initial nucleation and growth mechanism of potentiostatic Pd deposition were investigated via in situ e...Pd was electrochemically deposited on gold-coated quartz crystals at nanogram-level. The coulombic efficiency and initial nucleation and growth mechanism of potentiostatic Pd deposition were investigated via in situ electrochemical quartz crystal microbalance（EQCM）. The coulombic efficieneies are 84%, 93% and 95% for Pd deposition at 0.3, 0.2 and 0.1 V（vs. SCE）, respectively. The results of chronoamperometric measurements show that the Pd deposition proceeded by an instantaneous nucleation（at 0.3 V） or progressive nucleation（at 0.2 and 0.1 V） in a three-dimensional（3D） growth mode. The catalytic activity of Pd-based electrocatalyst for ethanol oxidation was characterized in an alkaline solution. It was found that the highest mass activity for ethanol oxidation on Pd-based electrocatalyst is 1.8× 10^4 A/（g Pd） deposited at 0.3 V for 5 s.展开更多
Soft electrochemical actuators that can generate mechanical motions in response to electrical stimuli can be used as artificial muscles in microscale robots.The electrode materials are the key component of the electro...Soft electrochemical actuators that can generate mechanical motions in response to electrical stimuli can be used as artificial muscles in microscale robots.The electrode materials are the key component of the electrochemical actuator because they limit the ion diffusion and accumulation processes and thus affect the deformation in fast response-time and potential engineering applications.Low-dimensional materials,such as one-dimensional(1D)CNT and two-dimensional(2D)vertically stood WS_(2),are great electrode due to their good electrochemical stability and high surface-to-volume ratios,but show limited performances when being used on their own in the actuators because of low reconstruction or low conductivity.A combination of 1D CNT and 2D WS_(2)could form a heterojunction with both high electrochemical activity and great mechanical stability.Herein,by depositing highly disordered graphene nanosheets(HDGNs)on CNT films and then WS_(2)on the formed low-dimensional nanocarbon film,a hybrid WS_(2)/HDGN/CNT film was synthesized through a multistep CVD method.Vertically grown WS_(2)nanosheets were achieved by taking advantage of HDGNs which limits CNTs sliding.So,the volume expansion caused by the transition from WO_(3)to WS-2can force the vertical growth of WS_(2).This hybrid film shows excellent electrochemical properties,such as high specific capacitance and high rate performance.Soft actuators based on the WS_(2)/HDGN/CNT films show good actuating performance,including stability and reconfigurability.展开更多
Layered LiCoO2 （HT-LiCoO2） films were grown on Pt-metalized silicon （PMS） substrates and polished bulk nickel （PBN） substrates by pulsed laser deposition. The effects of substrate temperature, oxygen pressure, a...Layered LiCoO2 （HT-LiCoO2） films were grown on Pt-metalized silicon （PMS） substrates and polished bulk nickel （PBN） substrates by pulsed laser deposition. The effects of substrate temperature, oxygen pressure, and substrate surface roughness on the microstructure of LiCoO2 films were investigated. It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 films. The HT-LiCoO2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains, whereas on PMS substrate, it is made up of loosely packed highly [001] preferential orientated triangular shaped grains with the average grain size less than 100 nm. Electrochemical measurements show that the highly [001] preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45μA·h·cm^-2·μm^-1 with a cycling efficiency of above 99% at the charge/discharge rate of 0.5 C.展开更多
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
Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locat...Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locations on gold nanorods, producing dumbbell-like nanostructures with PdAg at the ends of the gold nanorods or branched nanostructures with PdAg grown almost perpendicular to the gold nanorods. The nucleation sites of PdAg alloys on the gold nanorods can be effectively tuned by varying the concentrations of H2PdC14, AgNO3 and cetyltrimethylammonium bromide （CTAB）. The dumbbell-like and branched nanostructures were characterized by transmission electron microscopy （TEM）, high-resolution TEM （HRTEM）, line-scanning energy-dispersive X-ray spectros-copy （EDS）, X-ray photoelectron spectroscopy （XPS） and UV-Vis absorption spectroscopy. Their electrocatalytic performance was evaluated using ethanol oxidation as a probe reaction. The dumbbelMike nanostructures show a better anti-poisoning performance, but a worse electrochemical activity than the branched ones. The results provide guidelines for the controlled growth of complicated nanostructures for either fundamental studies or potential applications.展开更多
A novel strategy, which is better-suited for preparing materials with a very microscopic structure, is described and the whisker-like composite of Co(OH) 2/HY was prepared by using this strategy. In addition, the mech...A novel strategy, which is better-suited for preparing materials with a very microscopic structure, is described and the whisker-like composite of Co(OH) 2/HY was prepared by using this strategy. In addition, the mechanism by which the growth proceeds is not very rigorously worked out. Due to the high dispersed capability of HY towards to Co(OH) 2 resulting in loose whisker-like microstructure of Co(OH) 2, small channels become available for the diffusion of OH - electrolyte ions through all Co(OH) 2 thin layer. Consequentially, the prepared composite shows a very high specific capacitance (483 F/g) and utilization (93%) of effective electroactive composition of composite.展开更多
基金Supported by the Guangdong Science and Technology Key Projects, China(Nos.2007A010700001, 2007B090400032)Guangzhou Science and Technology Key Projects, China(Nos.2007Z1-D0051, SKT[2007]17-11) the Scientific Research Foundation for Young Teachers of the Sun Yat-Sen University, China(No.2006-31000-1131214)
文摘Pd was electrochemically deposited on gold-coated quartz crystals at nanogram-level. The coulombic efficiency and initial nucleation and growth mechanism of potentiostatic Pd deposition were investigated via in situ electrochemical quartz crystal microbalance（EQCM）. The coulombic efficieneies are 84%, 93% and 95% for Pd deposition at 0.3, 0.2 and 0.1 V（vs. SCE）, respectively. The results of chronoamperometric measurements show that the Pd deposition proceeded by an instantaneous nucleation（at 0.3 V） or progressive nucleation（at 0.2 and 0.1 V） in a three-dimensional（3D） growth mode. The catalytic activity of Pd-based electrocatalyst for ethanol oxidation was characterized in an alkaline solution. It was found that the highest mass activity for ethanol oxidation on Pd-based electrocatalyst is 1.8× 10^4 A/（g Pd） deposited at 0.3 V for 5 s.
基金financially supported by the National Natural Science Foundation of China(Nos.21975281 and 21773293)the National Key Research and Development Program of China(No.2020YFB1312902)。
文摘Soft electrochemical actuators that can generate mechanical motions in response to electrical stimuli can be used as artificial muscles in microscale robots.The electrode materials are the key component of the electrochemical actuator because they limit the ion diffusion and accumulation processes and thus affect the deformation in fast response-time and potential engineering applications.Low-dimensional materials,such as one-dimensional(1D)CNT and two-dimensional(2D)vertically stood WS_(2),are great electrode due to their good electrochemical stability and high surface-to-volume ratios,but show limited performances when being used on their own in the actuators because of low reconstruction or low conductivity.A combination of 1D CNT and 2D WS_(2)could form a heterojunction with both high electrochemical activity and great mechanical stability.Herein,by depositing highly disordered graphene nanosheets(HDGNs)on CNT films and then WS_(2)on the formed low-dimensional nanocarbon film,a hybrid WS_(2)/HDGN/CNT film was synthesized through a multistep CVD method.Vertically grown WS_(2)nanosheets were achieved by taking advantage of HDGNs which limits CNTs sliding.So,the volume expansion caused by the transition from WO_(3)to WS-2can force the vertical growth of WS_(2).This hybrid film shows excellent electrochemical properties,such as high specific capacitance and high rate performance.Soft actuators based on the WS_(2)/HDGN/CNT films show good actuating performance,including stability and reconfigurability.
基金This work was financially supported by the CERG(Competitive Earmarked Research Grant)grant from Research Grants Council of the Hong Kong Special Administrative Region,China(CityU 1316/03E)the National Natural Science Foundation of China(No.50401015)+1 种基金the Program of the Ministry of Education of China for Changjiang Scholars and Innovative Research Team in Universities(No.1RT 0551)the Natural Science Foundation of Guang-dong Province,China under the Team Project.
文摘Layered LiCoO2 （HT-LiCoO2） films were grown on Pt-metalized silicon （PMS） substrates and polished bulk nickel （PBN） substrates by pulsed laser deposition. The effects of substrate temperature, oxygen pressure, and substrate surface roughness on the microstructure of LiCoO2 films were investigated. It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 films. The HT-LiCoO2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains, whereas on PMS substrate, it is made up of loosely packed highly [001] preferential orientated triangular shaped grains with the average grain size less than 100 nm. Electrochemical measurements show that the highly [001] preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45μA·h·cm^-2·μm^-1 with a cycling efficiency of above 99% at the charge/discharge rate of 0.5 C.
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 Natural Science Foundation of China （Nos. 20801019, 21071055, 21172076）, New Century Excellent Talents in University （No. NCET-10-0369）, Shandong Provincial Natural Science Foundation for Distinguished Young Scholar （No. JQ201205）, Independent Innovation Foundations of Shandong University （No. 2012 ZD007）, new-faculty start-up funding in Shandong University and Key Laboratory of Fuel Cell Technology of Guangdong Province.
文摘Controllable growth of high-quality hybrid nanostructures is highly desirable for the fabrication of hierarchical, complex and multifunctional devices. Here, PdAg alloys have been controllably grown at different locations on gold nanorods, producing dumbbell-like nanostructures with PdAg at the ends of the gold nanorods or branched nanostructures with PdAg grown almost perpendicular to the gold nanorods. The nucleation sites of PdAg alloys on the gold nanorods can be effectively tuned by varying the concentrations of H2PdC14, AgNO3 and cetyltrimethylammonium bromide （CTAB）. The dumbbell-like and branched nanostructures were characterized by transmission electron microscopy （TEM）, high-resolution TEM （HRTEM）, line-scanning energy-dispersive X-ray spectros-copy （EDS）, X-ray photoelectron spectroscopy （XPS） and UV-Vis absorption spectroscopy. Their electrocatalytic performance was evaluated using ethanol oxidation as a probe reaction. The dumbbelMike nanostructures show a better anti-poisoning performance, but a worse electrochemical activity than the branched ones. The results provide guidelines for the controlled growth of complicated nanostructures for either fundamental studies or potential applications.
文摘A novel strategy, which is better-suited for preparing materials with a very microscopic structure, is described and the whisker-like composite of Co(OH) 2/HY was prepared by using this strategy. In addition, the mechanism by which the growth proceeds is not very rigorously worked out. Due to the high dispersed capability of HY towards to Co(OH) 2 resulting in loose whisker-like microstructure of Co(OH) 2, small channels become available for the diffusion of OH - electrolyte ions through all Co(OH) 2 thin layer. Consequentially, the prepared composite shows a very high specific capacitance (483 F/g) and utilization (93%) of effective electroactive composition of composite.
