The ternary catalyst Pt75Ru5Ni20 was conducted on various types of carbon supports including functionalized Vulcan XC-72R(f-CB),functionalized multi-walled carbon nanotubes(f-MWCNT),and mesoporous carbon(PC-Zn-succini...The ternary catalyst Pt75Ru5Ni20 was conducted on various types of carbon supports including functionalized Vulcan XC-72R(f-CB),functionalized multi-walled carbon nanotubes(f-MWCNT),and mesoporous carbon(PC-Zn-succinic)by sodium borohydride chemical reduction method to improve the ethanol electrooxidation reaction(EOR)for direct ethanol fuel cell(DEFC).It was found that the particle size of the metals on f-MWCNT was 5.20 nm with good particle dispersion.The alloy formation of ternary catalyst was confirmed by XRD and more clearly described by SEM element mapping,which was relevant to the efficiency of the catalysts.Moreover,the mechanism of ethanol electrooxidation reaction based on the surface reaction was more understanding.The activity and stability for ethanol electrooxidation reaction(EOR)were investigated using cyclic voltammetry and chronoamperometry,respectively.The highest activity and stability for EOR were observed from Pt75Ru5Ni20/f-MWCNT due to a good metal-carbon interaction.Ru and Ni presented in Pt-Ru-Ni alloy improved the activity and stability of ternary catalysts for EOR.Moreover,the reduction of Pt content in ternary catalyst led to the catalyst cost deduction in DEFC.展开更多
For the first time, we have obtained surface Raman spectra of dissociative adsorption of methanol at bare Pt electrodes of different surface roughness factors from 60 to 200 by using a confocal Raman microscope and a ...For the first time, we have obtained surface Raman spectra of dissociative adsorption of methanol at bare Pt electrodes of different surface roughness factors from 60 to 200 by using a confocal Raman microscope and a specific surface roughening procedure. Two bands at around 1 830 cm-1 and 2 040 cm-1 respectively have been assigned to the CO streching vibration of the dissociatively adsorbed CO as the poison Intermediate on the surface. In the low frequency region, the two correlated bands at ca 413 cm-1 and 494 cm-1 respectively provide a clear vibrational information that there exist the linear bonded Pt-CO and bridge bonded P’jO. On the Pt electrode with mild roughness, the Raman signal of CO peared at -0. 4 V, whereas it was still observable on the Pt electrode with high roughness.This reveals that the CO-substrate interaction is stronger for the platinum with the higher surface roughness, at least partly due to the supercluster interaction of the roughened electrode. In addition, the highly rough surface may be favorable to the formation of island CO,thus enhance the interaction between molecules. It has been shown that surface Raman spectroscopy has two advantages: first, It provides a uniquely sensitive probe for obtaining surface-adsorbate vibration information in the low frequency region which is typically not accessible to IR spectroscopy. Second, it can be applied to the study of highly roughened electrodes that are common for practical use. With its notable improvements in detection sensitivity and functions, Raman spectroscopy will probably become a powerful tool to in-situ study electrocatalysis of practical importance.展开更多
Platinum nanoparticles supported on carbon nanotubes (CNTs) were prepared by the chemical reduction method in solutions. The effects of reducing process and chemical modification of CNTs on the sizes and dispersion of...Platinum nanoparticles supported on carbon nanotubes (CNTs) were prepared by the chemical reduction method in solutions. The effects of reducing process and chemical modification of CNTs on the sizes and dispersion of nanoparticles were studied with SEM, TEM and XRD. It was demonstrated that the chemical modification of CNTs could improve their compatibility with solvents, hence the dispersibility of the platinum nanoparticles on CNTs. Among different reducing agents, including EG, NaBH4, HCHO and Na2S2O3, the smallest size, about 2.5 nm, and best dispersion of platinum nanoparticles were achieved by using EG as reductant under similar preparation conditions. The Pt/CNT catalyst prepared by EG reduction on H2SO4-modified CNTs exhibited excellent electrocatalytic activity for the direct methanol oxidation.展开更多
基金supported by the Institutional Research Grant(Thailand Research Fund:IRG598004)
文摘The ternary catalyst Pt75Ru5Ni20 was conducted on various types of carbon supports including functionalized Vulcan XC-72R(f-CB),functionalized multi-walled carbon nanotubes(f-MWCNT),and mesoporous carbon(PC-Zn-succinic)by sodium borohydride chemical reduction method to improve the ethanol electrooxidation reaction(EOR)for direct ethanol fuel cell(DEFC).It was found that the particle size of the metals on f-MWCNT was 5.20 nm with good particle dispersion.The alloy formation of ternary catalyst was confirmed by XRD and more clearly described by SEM element mapping,which was relevant to the efficiency of the catalysts.Moreover,the mechanism of ethanol electrooxidation reaction based on the surface reaction was more understanding.The activity and stability for ethanol electrooxidation reaction(EOR)were investigated using cyclic voltammetry and chronoamperometry,respectively.The highest activity and stability for EOR were observed from Pt75Ru5Ni20/f-MWCNT due to a good metal-carbon interaction.Ru and Ni presented in Pt-Ru-Ni alloy improved the activity and stability of ternary catalysts for EOR.Moreover,the reduction of Pt content in ternary catalyst led to the catalyst cost deduction in DEFC.
文摘For the first time, we have obtained surface Raman spectra of dissociative adsorption of methanol at bare Pt electrodes of different surface roughness factors from 60 to 200 by using a confocal Raman microscope and a specific surface roughening procedure. Two bands at around 1 830 cm-1 and 2 040 cm-1 respectively have been assigned to the CO streching vibration of the dissociatively adsorbed CO as the poison Intermediate on the surface. In the low frequency region, the two correlated bands at ca 413 cm-1 and 494 cm-1 respectively provide a clear vibrational information that there exist the linear bonded Pt-CO and bridge bonded P’jO. On the Pt electrode with mild roughness, the Raman signal of CO peared at -0. 4 V, whereas it was still observable on the Pt electrode with high roughness.This reveals that the CO-substrate interaction is stronger for the platinum with the higher surface roughness, at least partly due to the supercluster interaction of the roughened electrode. In addition, the highly rough surface may be favorable to the formation of island CO,thus enhance the interaction between molecules. It has been shown that surface Raman spectroscopy has two advantages: first, It provides a uniquely sensitive probe for obtaining surface-adsorbate vibration information in the low frequency region which is typically not accessible to IR spectroscopy. Second, it can be applied to the study of highly roughened electrodes that are common for practical use. With its notable improvements in detection sensitivity and functions, Raman spectroscopy will probably become a powerful tool to in-situ study electrocatalysis of practical importance.
文摘Platinum nanoparticles supported on carbon nanotubes (CNTs) were prepared by the chemical reduction method in solutions. The effects of reducing process and chemical modification of CNTs on the sizes and dispersion of nanoparticles were studied with SEM, TEM and XRD. It was demonstrated that the chemical modification of CNTs could improve their compatibility with solvents, hence the dispersibility of the platinum nanoparticles on CNTs. Among different reducing agents, including EG, NaBH4, HCHO and Na2S2O3, the smallest size, about 2.5 nm, and best dispersion of platinum nanoparticles were achieved by using EG as reductant under similar preparation conditions. The Pt/CNT catalyst prepared by EG reduction on H2SO4-modified CNTs exhibited excellent electrocatalytic activity for the direct methanol oxidation.
