Qiling Zhong - Academia.edu (original) (raw)
Papers by Qiling Zhong
Chemical Journal of Chinese Universities-chinese, 2014
Ag nanoparticles with two different particle sizes and uniform size-distribution were prepared at... more Ag nanoparticles with two different particle sizes and uniform size-distribution were prepared at18 ℃ by adjusting the adding amount of the NaOH solution,using silver nitrate as the precursor,polyvinylpyrrolidone( PVP) as the surfactant,ascorbic acid( AA) as the reductant. Pt hollow( Pthollow) nanospheres with different shell thicknesses and modified glassy carbon( GC) electrode( Pthollow/GC) were synthesized by adjusting the amount of precursor H2PtCl6·6H2O at room temperature,using Ag colloids as the template.The morphology,composition and structure of Pthollowwere characterized by scanning electron microscopy( SEM),high resolution transmission electron microscopy( HRTEM),energy-dispersive X-ray spectroscopy( EDS),X-ray diffraction( XRD) and other detection techniques; the electrocatalytic oxidation activity of Pthollow/GC,Pt solid nanoparticle modified GC( Ptnano/GC) electrode were studied and compared using methanol as a probe molecule. The results show that the Pthollownanosphe...
CIESC Journal, 2013
Platinum hollow nanospheres(PtHollow)were prepared in batch at room temperature by using selenium... more Platinum hollow nanospheres(PtHollow)were prepared in batch at room temperature by using selenium nanospheres as template,chloroplatinic acid precursor,ascorbic acid as reducing agent and SDSN as stabilizing agent,and the prepared platinum hollow spheres were used to modify glassy carbon electrode(PtHollow/GC).In addition,electro-deposition platinum nanoparticles modified glassy carbon electrode(Ptnano/GC)was prepared for comparison.The morphology and structure were characterized with X-ray diffraction,scanning electron microscopy and transmission electron microscope.Platinum hollow nanospheres had excellent dispersion and uniform size,and the diameter was about 120 nm.The shell was porous with a thickness smaller than 10 nm and was constructed by multi-dimensional and multi-level Pt atoms clusters.Formaldehyde was used as probe molecules,and the conventional electrochemical methods,including cyclic voltammetry and chronoamperometry curves were used to test the catalytic performance...
By means of Surface - enhanced Raman Spectroscopy ( SERS), Time -resolved Surface - enhanced Rama... more By means of Surface - enhanced Raman Spectroscopy ( SERS), Time -resolved Surface - enhanced Raman Spectroscopy (TRSERS) and potential step method, the coadsorption behavior of methyl thiourea (MTU) and 1 - allyl - 2 -thiourea (ATU) with ClO4- respectively at Ag electrodes has been studied. The SERS intensity - time profiles show that the intensities of different SERS bands have surprisingly different response rates to the potential step. The response rates of the groups of the adsorbed species which is close to the electrode surface are fast. The results also indicate that MTU is vertically adsorbed on Ag electrode surface via S atom, while ATU is adsorbed on the surface via S atom and the molecules leaned to the electrode surface.
Acta Physico-Chimica Sinica, 2006
TheelectrooxidationbehaviorofformicacidonPt鄄Ru/GCelectrodewasinvestigatedbyCV,multi鄄 potentialste... more TheelectrooxidationbehaviorofformicacidonPt鄄Ru/GCelectrodewasinvestigatedbyCV,multi鄄 potentialstepsandSERS.ItwasfoundthatformicacidcoulddissociatespontaneouslyonPt鄄Ru/GCelectrodeasit dissociatedonroughPtelectrode,producestrongabsorptionintermediateCOandreactiveintermediate-COO-.The resultsdemonstratedthatRucouldimprovetheelectrocatalyticactivityofformicacidonPt鄄Ru/GCelectrode.Asthe ratioofPtandRuindespositionsolutionchangedfrom10颐1to1颐 1,theoxidationpotentialofCOshiftednegatively about60mV(from0.41Vto0.35V).ComparedtoroughPtelectrode,theoxidationpotentialofCOonPt鄄Ru/GC(1颐1) shiftednegatively200mV.TheseresultsindicatethatSERSishopefultobeacomprehensivespectroscopytoolof investigatingtheelectrocatalyticreactionmechanism.
Chemical Journal of Chinese Universities-chinese, Dec 10, 2014
以Se溶胶为模板, 合成了多层核壳结构的Se@Pt@Au@Pt实心纳米粒子; 采用化学与电化学相结合的除硒方法制得了(PtAuPt)HN/GC, 并表征了(PtAuPt-Se)HN的表面形貌、结... more 以Se溶胶为模板, 合成了多层核壳结构的Se@Pt@Au@Pt实心纳米粒子; 采用化学与电化学相结合的除硒方法制得了(PtAuPt)HN/GC, 并表征了(PtAuPt-Se)HN的表面形貌、结构与组成; 以甲酸为探针分子, 比较了(PtAuPt)HN/GC和Pt/C/GC对甲酸氧化的电催化行为, 发现(PtAuPt)HN/GC催化甲酸氧化只有1个氧化峰, 峰电位和峰电流分别约为0.35 V和1.22 mA/cm2, 而Pt/C/GC则有2个氧化峰, 在 0.35 V时所对应的电流密度仅约为0.30 mA/cm2, 前者在该电位时的电流密度是后者的4倍; 在0.30 mA/cm2的电流密度下, (PtAuPt)HN /GC对应的电极电位为0.01 V, 比Pt/C/GC负移了340 mV; 在600 s时的计时电流分别为0.06和0.02 mA/cm2. (PtAuPt)HN对甲酸氧化的电催化活性不但比Pt/C高, 而且具有一定的抗CO中毒性能.
Angewandte Chemie (International ed. in English), Jan 4, 2015
Quantitative analysis is a great challenge in surface-enhanced Raman scattering (SERS). Core-mole... more Quantitative analysis is a great challenge in surface-enhanced Raman scattering (SERS). Core-molecule-shell nanoparticles with two components in the molecular layer, a framework molecule to form the shell, and a probe molecule as a Raman internal standard, were rationally designed for quantitative SERS analysis. The signal of the embedded Raman probe provides effective feedback to correct the fluctuation of samples and measuring conditions. Meanwhile, target molecules with different affinities can be adsorbed onto the shell. The quantitative analysis of target molecules over a large concentration range has been demonstrated with a linear response of the relative SERS intensity versus the surface coverage, which has not been achieved by conventional SERS methods.
Guang pu xue yu guang pu fen xi = Guang pu, 2004
The electrooxidation behavior of HCHO on a roughened platinum electrode was studied by cyclic vol... more The electrooxidation behavior of HCHO on a roughened platinum electrode was studied by cyclic voltammetry. Two factors that influence the electrooxidation behavior of HCHO, i.e. the concentration of the supporting electrolyte and the structure of the electrode surface were taken into account. The dissociative adsorption behavior of HCHO on a roughened platinum electrode was investigated by confocal microprobe Raman spectroscopy in-situ, and the spontaneous dissociative adsorption behavior of HCHO on a roughened platinum electrode was found by CV and was confirmed at the molecule level by in-situ Raman spectra.
SCIENTIA SINICA Chimica, 2013
Pt hollow nanospheres with different shell thicknesses were synthesized by adjusting the amount o... more Pt hollow nanospheres with different shell thicknesses were synthesized by adjusting the amount of precursor H 2 PtCl 6 , using 120 nm of α -selenium colloids as the template, ascorbic acid as the reducing agent, and SDSN as stabilizing agent. The prepared platinum hollow spheres were drop-coated to modify the glassy carbon electrode (Pt hollow /GC) and used as the working electrode. Scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive X-ray spectrum (EDX), X-ray diffraction (XRD) and selected area electron diffraction (SAED) were used to determine the morphology and structure. The electrocatalytic oxidation behavior of formic acid on the modified electrodes was evaluated by cyclic voltammetry and chronoamperometry. The results show that the Pt hollow nanospheres have a uniform particle size and good dispersity. The shell of the spheres were made of Pt clusters of various size, showing the similar structure and propertie to that of the polycrystalline platinum. Hollow nanospheres showed different electrocatalytic activity on the oxidation formic acid at a different molar ratio between Se and Pt. The Pt hollow nanosphere with a molar ratio of 1:1.2 shows the highest activity, and is much more active than the electrodeposited Pt on glassy carbon surface. These provides theoretical and experimental conditions for the anode material of direct formic fuel cell, and has potential value of application.
Frontiers of Chemistry in China, 2008
The morphology and structure of Pt-CNTs/ GC electrodes were characterized via Transmission Electr... more The morphology and structure of Pt-CNTs/ GC electrodes were characterized via Transmission Electron Microscopy (TEM) and selected area electron diffraction. The electro-oxidation behavior of CO and methanol on Pt-CNTs/GC electrodes were studied with cyclic voltommograms or chronoamperometry. Three oxidation peaks were observed for CO absorbed on Pt-CNTs/GC electrodes. Methanol was found to be dissociated spontaneously on the electrode to produce a strong absorbed intermediate CO. Among the three oxidation peaks, peak I was presumed to be due to the bridged CO absorption while peaks II and III were attributed to the split in the linear CO which is absorbed on the Pt-CNTs/GC nanocluster with different particle size and Pt film. The oxidation current of methanol on the Pt-CNTs/ GC electrode did not always increase with the increase in the amount of Pt loading. The result indicates that there is an optimal Pt loading for methanol oxidation. It is necessary to select the catalyst with proper Pt loading when the anode of a direct-methanol fuel cell is prepared.
Langmuir, 2005
Core-shell Au-Pt nanoparticles were synthesized by using a seed growth method and characterized b... more Core-shell Au-Pt nanoparticles were synthesized by using a seed growth method and characterized by transmission electron microscopy, X-ray diffraction, and UV-vis spectroscopy. Aucore-Ptshell/GC electrodes were prepared by drop-coating the nanoparticles on clean glassy carbon (GC) surfaces, and their electrochemical behavior in 0.5 M H 2SO4 revealed that coating of the Au core by the Pt shell is complete. The electrooxidation of carbon monoxide and methanol on the Aucore-Ptshell/GC was also examined, and the results are similar to those obtained on a bulk Pt electrode. High quality surface-enhanced Raman scattering (SERS) spectra of both adsorbed CO and thiocyanate were observed on the Au core-Ptshell/GC electrodes. The potential-dependent SERS features resemble those obtained on electrochemically roughened bulk Pt or Pt thin films deposited on roughened Au electrodes. For thiocyanate, the C-N stretching frequency increases with the applied potential, yielding two distinctly different dνCN/dE. From-0.8 to-0.2 V, the dνCN/dE is ca. 50 cm-1 /V, whereas it is 90 cm-1 /V above 0 V. The bandwidth along with the band intensity increases sharply above 0 V. At the low-frequency region, Pt-NCS stretching mode at 350 cm-1 was observed at the potentials from-0.8 to 0 V, whereas the Pt-SCN mode at 280 cm-1 was largely absent until around 0 V and became dominant at more positive potentials. These potential-dependent spectral transitions were attributed to the adsorption orientation switch from N-bound dominant at the negative potential region to S-bound at more positive potentials. The origin of the SERS activity of the particles is briefly discussed. The study demonstrates a new method of obtaining high quality SERS on Pt-group transition metals, with the possibility of tuning SERS activity by varying the core size and the shell thickness.
Chinese Journal of Chemistry, 2007
The electrochemical and in-situ surface-enhanced Raman spectroscopy (SERS) techniques were used t... more The electrochemical and in-situ surface-enhanced Raman spectroscopy (SERS) techniques were used to investigate the electrooxidation behavior of methanol in acidic, neutral and alkaline media at a Pt-Ru nanoparticle modified glassy carbon (Pt-Ru/GC) electrode. The results showed that methanol could be dissociated spontaneously at the Pt-Ru/GC electrode to produce a strongly adsorbed intermediate, CO. It was found that CO could be oxidized more easily in the alkaline medium than in the acidic and neutral media. The peak potential of methanol oxidation was shifted from 0.663 and 0.708 V in the acidic and neutral media to-0.030 V in the alkaline medium, which is due to that the adsorption strength of CO on the Pt surface in the alkaline medium is weaker than that in the acidic and neutral media. The final product of the methanol oxidation is CO 2. However, in the alkaline medium, CO 2 produced would form 2 3 CO − and 3 HCO − resulting in the decrease in the alkaline concentration and then in the decrease in the performance of DMFC. Therefore, the performance of the alkaline DMFC is not stable.
Chemical Physics Letters, 2003
Surface-enhanced Raman spectra (SERS) from a roughened platinum electrode in formic acid-containi... more Surface-enhanced Raman spectra (SERS) from a roughened platinum electrode in formic acid-containing dimethylformamide solutions have been examined combined with cyclic voltammetry techniques. The occurrence of surface poisoning by CO adsorption was confirmed by observation of both Pt-CO and internal CO modes simultaneously. Oxidation of HCOOH can occur to a large extent only after the desorption of CO from the surface. Similar observations were also obtained in absolute methanol solutions. Linearly bound CO on platinum was suggested for both nonaqueous systems. In addition, a high electro-catalytic activity for the present roughened SERS-active platinum surface was also assumed compared with smooth platinum surfaces.
Core-shell nanostructure Au@Pt nanoparticles were synthesized with a diameter of 100 nm Au nanopa... more Core-shell nanostructure Au@Pt nanoparticles were synthesized with a diameter of 100 nm Au nanoparticles as cores,ascorbic acid as reducing agent and H2PtCl6·6H2O as the precursor.The synthesized nanoparticles and commercial electrocatalysts were dropped on glassy carbon electrodes(Au@Pt/GC) to form the oxygen reduction electrodes(Au@Pt/GC,Pt/C/GC).The reaction activities for oxygen reduction and methanol tolerance of Au@Pt/GC and commercial Pt/C/GC electrodes were compared with those of rotating disk electrode and other conventional electrochemical methods.At a significantly reduced amount of Pt,the oxygen reduction activity of Au@Pt nanoparticles is still comparable with the commercial Pt/C.The oxygen reduction proceeds via a four-electron transfer reaction to water on Au@Pt nanoparticles.Futhermore,it shows a good tolerance to methanol.
Chemical Journal of Chinese Universities-chinese, 2014
Ag nanoparticles with two different particle sizes and uniform size-distribution were prepared at... more Ag nanoparticles with two different particle sizes and uniform size-distribution were prepared at18 ℃ by adjusting the adding amount of the NaOH solution,using silver nitrate as the precursor,polyvinylpyrrolidone( PVP) as the surfactant,ascorbic acid( AA) as the reductant. Pt hollow( Pthollow) nanospheres with different shell thicknesses and modified glassy carbon( GC) electrode( Pthollow/GC) were synthesized by adjusting the amount of precursor H2PtCl6·6H2O at room temperature,using Ag colloids as the template.The morphology,composition and structure of Pthollowwere characterized by scanning electron microscopy( SEM),high resolution transmission electron microscopy( HRTEM),energy-dispersive X-ray spectroscopy( EDS),X-ray diffraction( XRD) and other detection techniques; the electrocatalytic oxidation activity of Pthollow/GC,Pt solid nanoparticle modified GC( Ptnano/GC) electrode were studied and compared using methanol as a probe molecule. The results show that the Pthollownanosphe...
CIESC Journal, 2013
Platinum hollow nanospheres(PtHollow)were prepared in batch at room temperature by using selenium... more Platinum hollow nanospheres(PtHollow)were prepared in batch at room temperature by using selenium nanospheres as template,chloroplatinic acid precursor,ascorbic acid as reducing agent and SDSN as stabilizing agent,and the prepared platinum hollow spheres were used to modify glassy carbon electrode(PtHollow/GC).In addition,electro-deposition platinum nanoparticles modified glassy carbon electrode(Ptnano/GC)was prepared for comparison.The morphology and structure were characterized with X-ray diffraction,scanning electron microscopy and transmission electron microscope.Platinum hollow nanospheres had excellent dispersion and uniform size,and the diameter was about 120 nm.The shell was porous with a thickness smaller than 10 nm and was constructed by multi-dimensional and multi-level Pt atoms clusters.Formaldehyde was used as probe molecules,and the conventional electrochemical methods,including cyclic voltammetry and chronoamperometry curves were used to test the catalytic performance...
By means of Surface - enhanced Raman Spectroscopy ( SERS), Time -resolved Surface - enhanced Rama... more By means of Surface - enhanced Raman Spectroscopy ( SERS), Time -resolved Surface - enhanced Raman Spectroscopy (TRSERS) and potential step method, the coadsorption behavior of methyl thiourea (MTU) and 1 - allyl - 2 -thiourea (ATU) with ClO4- respectively at Ag electrodes has been studied. The SERS intensity - time profiles show that the intensities of different SERS bands have surprisingly different response rates to the potential step. The response rates of the groups of the adsorbed species which is close to the electrode surface are fast. The results also indicate that MTU is vertically adsorbed on Ag electrode surface via S atom, while ATU is adsorbed on the surface via S atom and the molecules leaned to the electrode surface.
Acta Physico-Chimica Sinica, 2006
TheelectrooxidationbehaviorofformicacidonPt鄄Ru/GCelectrodewasinvestigatedbyCV,multi鄄 potentialste... more TheelectrooxidationbehaviorofformicacidonPt鄄Ru/GCelectrodewasinvestigatedbyCV,multi鄄 potentialstepsandSERS.ItwasfoundthatformicacidcoulddissociatespontaneouslyonPt鄄Ru/GCelectrodeasit dissociatedonroughPtelectrode,producestrongabsorptionintermediateCOandreactiveintermediate-COO-.The resultsdemonstratedthatRucouldimprovetheelectrocatalyticactivityofformicacidonPt鄄Ru/GCelectrode.Asthe ratioofPtandRuindespositionsolutionchangedfrom10颐1to1颐 1,theoxidationpotentialofCOshiftednegatively about60mV(from0.41Vto0.35V).ComparedtoroughPtelectrode,theoxidationpotentialofCOonPt鄄Ru/GC(1颐1) shiftednegatively200mV.TheseresultsindicatethatSERSishopefultobeacomprehensivespectroscopytoolof investigatingtheelectrocatalyticreactionmechanism.
Chemical Journal of Chinese Universities-chinese, Dec 10, 2014
以Se溶胶为模板, 合成了多层核壳结构的Se@Pt@Au@Pt实心纳米粒子; 采用化学与电化学相结合的除硒方法制得了(PtAuPt)HN/GC, 并表征了(PtAuPt-Se)HN的表面形貌、结... more 以Se溶胶为模板, 合成了多层核壳结构的Se@Pt@Au@Pt实心纳米粒子; 采用化学与电化学相结合的除硒方法制得了(PtAuPt)HN/GC, 并表征了(PtAuPt-Se)HN的表面形貌、结构与组成; 以甲酸为探针分子, 比较了(PtAuPt)HN/GC和Pt/C/GC对甲酸氧化的电催化行为, 发现(PtAuPt)HN/GC催化甲酸氧化只有1个氧化峰, 峰电位和峰电流分别约为0.35 V和1.22 mA/cm2, 而Pt/C/GC则有2个氧化峰, 在 0.35 V时所对应的电流密度仅约为0.30 mA/cm2, 前者在该电位时的电流密度是后者的4倍; 在0.30 mA/cm2的电流密度下, (PtAuPt)HN /GC对应的电极电位为0.01 V, 比Pt/C/GC负移了340 mV; 在600 s时的计时电流分别为0.06和0.02 mA/cm2. (PtAuPt)HN对甲酸氧化的电催化活性不但比Pt/C高, 而且具有一定的抗CO中毒性能.
Angewandte Chemie (International ed. in English), Jan 4, 2015
Quantitative analysis is a great challenge in surface-enhanced Raman scattering (SERS). Core-mole... more Quantitative analysis is a great challenge in surface-enhanced Raman scattering (SERS). Core-molecule-shell nanoparticles with two components in the molecular layer, a framework molecule to form the shell, and a probe molecule as a Raman internal standard, were rationally designed for quantitative SERS analysis. The signal of the embedded Raman probe provides effective feedback to correct the fluctuation of samples and measuring conditions. Meanwhile, target molecules with different affinities can be adsorbed onto the shell. The quantitative analysis of target molecules over a large concentration range has been demonstrated with a linear response of the relative SERS intensity versus the surface coverage, which has not been achieved by conventional SERS methods.
Guang pu xue yu guang pu fen xi = Guang pu, 2004
The electrooxidation behavior of HCHO on a roughened platinum electrode was studied by cyclic vol... more The electrooxidation behavior of HCHO on a roughened platinum electrode was studied by cyclic voltammetry. Two factors that influence the electrooxidation behavior of HCHO, i.e. the concentration of the supporting electrolyte and the structure of the electrode surface were taken into account. The dissociative adsorption behavior of HCHO on a roughened platinum electrode was investigated by confocal microprobe Raman spectroscopy in-situ, and the spontaneous dissociative adsorption behavior of HCHO on a roughened platinum electrode was found by CV and was confirmed at the molecule level by in-situ Raman spectra.
SCIENTIA SINICA Chimica, 2013
Pt hollow nanospheres with different shell thicknesses were synthesized by adjusting the amount o... more Pt hollow nanospheres with different shell thicknesses were synthesized by adjusting the amount of precursor H 2 PtCl 6 , using 120 nm of α -selenium colloids as the template, ascorbic acid as the reducing agent, and SDSN as stabilizing agent. The prepared platinum hollow spheres were drop-coated to modify the glassy carbon electrode (Pt hollow /GC) and used as the working electrode. Scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), energy dispersive X-ray spectrum (EDX), X-ray diffraction (XRD) and selected area electron diffraction (SAED) were used to determine the morphology and structure. The electrocatalytic oxidation behavior of formic acid on the modified electrodes was evaluated by cyclic voltammetry and chronoamperometry. The results show that the Pt hollow nanospheres have a uniform particle size and good dispersity. The shell of the spheres were made of Pt clusters of various size, showing the similar structure and propertie to that of the polycrystalline platinum. Hollow nanospheres showed different electrocatalytic activity on the oxidation formic acid at a different molar ratio between Se and Pt. The Pt hollow nanosphere with a molar ratio of 1:1.2 shows the highest activity, and is much more active than the electrodeposited Pt on glassy carbon surface. These provides theoretical and experimental conditions for the anode material of direct formic fuel cell, and has potential value of application.
Frontiers of Chemistry in China, 2008
The morphology and structure of Pt-CNTs/ GC electrodes were characterized via Transmission Electr... more The morphology and structure of Pt-CNTs/ GC electrodes were characterized via Transmission Electron Microscopy (TEM) and selected area electron diffraction. The electro-oxidation behavior of CO and methanol on Pt-CNTs/GC electrodes were studied with cyclic voltommograms or chronoamperometry. Three oxidation peaks were observed for CO absorbed on Pt-CNTs/GC electrodes. Methanol was found to be dissociated spontaneously on the electrode to produce a strong absorbed intermediate CO. Among the three oxidation peaks, peak I was presumed to be due to the bridged CO absorption while peaks II and III were attributed to the split in the linear CO which is absorbed on the Pt-CNTs/GC nanocluster with different particle size and Pt film. The oxidation current of methanol on the Pt-CNTs/ GC electrode did not always increase with the increase in the amount of Pt loading. The result indicates that there is an optimal Pt loading for methanol oxidation. It is necessary to select the catalyst with proper Pt loading when the anode of a direct-methanol fuel cell is prepared.
Langmuir, 2005
Core-shell Au-Pt nanoparticles were synthesized by using a seed growth method and characterized b... more Core-shell Au-Pt nanoparticles were synthesized by using a seed growth method and characterized by transmission electron microscopy, X-ray diffraction, and UV-vis spectroscopy. Aucore-Ptshell/GC electrodes were prepared by drop-coating the nanoparticles on clean glassy carbon (GC) surfaces, and their electrochemical behavior in 0.5 M H 2SO4 revealed that coating of the Au core by the Pt shell is complete. The electrooxidation of carbon monoxide and methanol on the Aucore-Ptshell/GC was also examined, and the results are similar to those obtained on a bulk Pt electrode. High quality surface-enhanced Raman scattering (SERS) spectra of both adsorbed CO and thiocyanate were observed on the Au core-Ptshell/GC electrodes. The potential-dependent SERS features resemble those obtained on electrochemically roughened bulk Pt or Pt thin films deposited on roughened Au electrodes. For thiocyanate, the C-N stretching frequency increases with the applied potential, yielding two distinctly different dνCN/dE. From-0.8 to-0.2 V, the dνCN/dE is ca. 50 cm-1 /V, whereas it is 90 cm-1 /V above 0 V. The bandwidth along with the band intensity increases sharply above 0 V. At the low-frequency region, Pt-NCS stretching mode at 350 cm-1 was observed at the potentials from-0.8 to 0 V, whereas the Pt-SCN mode at 280 cm-1 was largely absent until around 0 V and became dominant at more positive potentials. These potential-dependent spectral transitions were attributed to the adsorption orientation switch from N-bound dominant at the negative potential region to S-bound at more positive potentials. The origin of the SERS activity of the particles is briefly discussed. The study demonstrates a new method of obtaining high quality SERS on Pt-group transition metals, with the possibility of tuning SERS activity by varying the core size and the shell thickness.
Chinese Journal of Chemistry, 2007
The electrochemical and in-situ surface-enhanced Raman spectroscopy (SERS) techniques were used t... more The electrochemical and in-situ surface-enhanced Raman spectroscopy (SERS) techniques were used to investigate the electrooxidation behavior of methanol in acidic, neutral and alkaline media at a Pt-Ru nanoparticle modified glassy carbon (Pt-Ru/GC) electrode. The results showed that methanol could be dissociated spontaneously at the Pt-Ru/GC electrode to produce a strongly adsorbed intermediate, CO. It was found that CO could be oxidized more easily in the alkaline medium than in the acidic and neutral media. The peak potential of methanol oxidation was shifted from 0.663 and 0.708 V in the acidic and neutral media to-0.030 V in the alkaline medium, which is due to that the adsorption strength of CO on the Pt surface in the alkaline medium is weaker than that in the acidic and neutral media. The final product of the methanol oxidation is CO 2. However, in the alkaline medium, CO 2 produced would form 2 3 CO − and 3 HCO − resulting in the decrease in the alkaline concentration and then in the decrease in the performance of DMFC. Therefore, the performance of the alkaline DMFC is not stable.
Chemical Physics Letters, 2003
Surface-enhanced Raman spectra (SERS) from a roughened platinum electrode in formic acid-containi... more Surface-enhanced Raman spectra (SERS) from a roughened platinum electrode in formic acid-containing dimethylformamide solutions have been examined combined with cyclic voltammetry techniques. The occurrence of surface poisoning by CO adsorption was confirmed by observation of both Pt-CO and internal CO modes simultaneously. Oxidation of HCOOH can occur to a large extent only after the desorption of CO from the surface. Similar observations were also obtained in absolute methanol solutions. Linearly bound CO on platinum was suggested for both nonaqueous systems. In addition, a high electro-catalytic activity for the present roughened SERS-active platinum surface was also assumed compared with smooth platinum surfaces.
Core-shell nanostructure Au@Pt nanoparticles were synthesized with a diameter of 100 nm Au nanopa... more Core-shell nanostructure Au@Pt nanoparticles were synthesized with a diameter of 100 nm Au nanoparticles as cores,ascorbic acid as reducing agent and H2PtCl6·6H2O as the precursor.The synthesized nanoparticles and commercial electrocatalysts were dropped on glassy carbon electrodes(Au@Pt/GC) to form the oxygen reduction electrodes(Au@Pt/GC,Pt/C/GC).The reaction activities for oxygen reduction and methanol tolerance of Au@Pt/GC and commercial Pt/C/GC electrodes were compared with those of rotating disk electrode and other conventional electrochemical methods.At a significantly reduced amount of Pt,the oxygen reduction activity of Au@Pt nanoparticles is still comparable with the commercial Pt/C.The oxygen reduction proceeds via a four-electron transfer reaction to water on Au@Pt nanoparticles.Futhermore,it shows a good tolerance to methanol.