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
Developing new catalysts to decorate photoelectrodes has been widely used to enhance the performance of photoelectrochemical(PEC)cells.However,the high cost,complex synthesis,and poor stability of catalyst decoration ...Developing new catalysts to decorate photoelectrodes has been widely used to enhance the performance of photoelectrochemical(PEC)cells.However,the high cost,complex synthesis,and poor stability of catalyst decoration strongly hinder its practical application.Here,we report a facile and low-cost decoration of Ag-Pt nanoparticles(Ag-Pt NPs)on Si photocathodes with TiO_(2)/Ti sacrificial overlayers.Such a decoration does not rely on any metallic-ion precursor solution since it is formed automatically via galvanic replacement reactions during PEC measurements;that is,Ti is displaced by Ag^(+)and Pt^(2+)ions,which are from the employed reference and counter electrodes,respectively.The as-decorated Ag-Pt NPs are verified to significantly enhance the hydrogen evolution reduction kinetics without substantially degrading the optical performance of Si photocathodes.Owing to optoelectronic advantages,the overpotential required to maintain a photocurrent density of 10 mA cm(under AM1.5 G illumination)is reduced from-0.8 V_(RHE)(for the bare planar Si photocathode)to-0.1 V_(RHE)(for the planar Si photocathode with Ag-Pt NP decoration).Moreover,a further anodic shift(to 0 V_(RHE))is visible for the Si nanowire array photocathode with Ag-Pt NP decoration,along with high long-term stability of the PEC response in acidic and neutral electrolytes.This study opens a new opportunity for the photo-assisted decoration of various alloy NPs on the morphology-varying photoelectrodes with different applications.展开更多
Nanoporous Ag-Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5.The noble Ag and Pt were left after the less noble Cu and ...Nanoporous Ag-Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5.The noble Ag and Pt were left after the less noble Cu and Si dissolved in a certain acid solution.Bi-continuous nanoporous microstructure was formed with asymmetric ligaments and pores with typically 30-200 nm in width.The trace addition of Pt has refined the grains of the ligaments to the average size of less than 20 nm in the substrate and induced the formation of rods with nanopores.The morphologies of the rods were observed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)both in the form of clusters and as scattered individuals with characteristic length of several micrometers and diameter of tens of nanometers.The grains sizes in the rods were finer than those in the ligaments.The good mechanical integrity might be due to the combination of continuous ligaments and clusters of rods.展开更多
A power-law (y = cx<sup>n</sup>) signature between process energy budget (kJ) and process energy density (kJ·ml<sup>-1</sup>) of microwave-assisted synthesis of silver and gold nanostructu...A power-law (y = cx<sup>n</sup>) signature between process energy budget (kJ) and process energy density (kJ·ml<sup>-1</sup>) of microwave-assisted synthesis of silver and gold nanostructures has been recently described [Law and Denis. AJAC, 14(4), 149-174, (2023)]. This study explores this relation further for palladium, platinum, and zinc oxide nanostructures. Parametric cluster analysis and statistical analysis is used to test the power-law signature of over four orders of magnitude as a function of six microwave applicator-types metal precursor, non-Green Chemistry synthesis and claimed Green Chemistry. It is found that for the claimed Green Chemistry, process energy budget ranges from 0.291 to 900 kJ, with a residual error ranging between −33 to +25.9 kJ·ml<sup>-1</sup>. The non-Green Chemistry synthesis has a higher process energy budget range from 3.2 kJ to 3.3 MJ, with a residual error of −33.3 to +245.3 kJ·ml<sup>-1</sup>. It is also found that the energy profile over time produced by software controlled digestion applicators is poorly reported which leads to residual error problematic outliers that produce possible phase-transition in the power-law signature. The original Au and Ag database and new Pd, Pt and ZnO database (with and without problematic outliers) yield a global microwave-assisted synthesis power-law signature constants of c = 0.7172 ± 0.3214 kJ·ml<sup>-1</sup> at x-axes = 0.001 kJ, and the exponent, n = 0.791 ± 0.055. The information in this study is aimed to understand variations in historical microwave-assisted synthesis processes, and develop new scale-out synthesis through process intensification.展开更多
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.
基金supported by the National Natural Science Foundation of China(62075146 and 61875143)the Natural Science Foundation of Jiangsu Province(BK20181169)+3 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions(20KJA510003)Qinglan Project of Jiangsu Provincethe Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutionsthe Natural Science Research of Jiangsu Higher Education Institutions。
文摘Developing new catalysts to decorate photoelectrodes has been widely used to enhance the performance of photoelectrochemical(PEC)cells.However,the high cost,complex synthesis,and poor stability of catalyst decoration strongly hinder its practical application.Here,we report a facile and low-cost decoration of Ag-Pt nanoparticles(Ag-Pt NPs)on Si photocathodes with TiO_(2)/Ti sacrificial overlayers.Such a decoration does not rely on any metallic-ion precursor solution since it is formed automatically via galvanic replacement reactions during PEC measurements;that is,Ti is displaced by Ag^(+)and Pt^(2+)ions,which are from the employed reference and counter electrodes,respectively.The as-decorated Ag-Pt NPs are verified to significantly enhance the hydrogen evolution reduction kinetics without substantially degrading the optical performance of Si photocathodes.Owing to optoelectronic advantages,the overpotential required to maintain a photocurrent density of 10 mA cm(under AM1.5 G illumination)is reduced from-0.8 V_(RHE)(for the bare planar Si photocathode)to-0.1 V_(RHE)(for the planar Si photocathode with Ag-Pt NP decoration).Moreover,a further anodic shift(to 0 V_(RHE))is visible for the Si nanowire array photocathode with Ag-Pt NP decoration,along with high long-term stability of the PEC response in acidic and neutral electrolytes.This study opens a new opportunity for the photo-assisted decoration of various alloy NPs on the morphology-varying photoelectrodes with different applications.
基金financially supported by the China Postdoctoral Science Foundation(No.2015M570964)the National Key Research and Development Program of China(No.2017YFB0304504)。
文摘Nanoporous Ag-Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5.The noble Ag and Pt were left after the less noble Cu and Si dissolved in a certain acid solution.Bi-continuous nanoporous microstructure was formed with asymmetric ligaments and pores with typically 30-200 nm in width.The trace addition of Pt has refined the grains of the ligaments to the average size of less than 20 nm in the substrate and induced the formation of rods with nanopores.The morphologies of the rods were observed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)both in the form of clusters and as scattered individuals with characteristic length of several micrometers and diameter of tens of nanometers.The grains sizes in the rods were finer than those in the ligaments.The good mechanical integrity might be due to the combination of continuous ligaments and clusters of rods.
文摘A power-law (y = cx<sup>n</sup>) signature between process energy budget (kJ) and process energy density (kJ·ml<sup>-1</sup>) of microwave-assisted synthesis of silver and gold nanostructures has been recently described [Law and Denis. AJAC, 14(4), 149-174, (2023)]. This study explores this relation further for palladium, platinum, and zinc oxide nanostructures. Parametric cluster analysis and statistical analysis is used to test the power-law signature of over four orders of magnitude as a function of six microwave applicator-types metal precursor, non-Green Chemistry synthesis and claimed Green Chemistry. It is found that for the claimed Green Chemistry, process energy budget ranges from 0.291 to 900 kJ, with a residual error ranging between −33 to +25.9 kJ·ml<sup>-1</sup>. The non-Green Chemistry synthesis has a higher process energy budget range from 3.2 kJ to 3.3 MJ, with a residual error of −33.3 to +245.3 kJ·ml<sup>-1</sup>. It is also found that the energy profile over time produced by software controlled digestion applicators is poorly reported which leads to residual error problematic outliers that produce possible phase-transition in the power-law signature. The original Au and Ag database and new Pd, Pt and ZnO database (with and without problematic outliers) yield a global microwave-assisted synthesis power-law signature constants of c = 0.7172 ± 0.3214 kJ·ml<sup>-1</sup> at x-axes = 0.001 kJ, and the exponent, n = 0.791 ± 0.055. The information in this study is aimed to understand variations in historical microwave-assisted synthesis processes, and develop new scale-out synthesis through process intensification.
