Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% p...Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% platinum per carbon were prepared by the three methods; their morphology and electrocatalytic activities were characterized.The 20 wt.% Pt-WO3/C catalyst prepared by the co-impregnation/EG method presented the optimal dispersion with an average particle size of 4.6 nm and subsequently the best electrocatalytic activity,and so,it was further characterized.Its anodic peak current density for ethanol oxidation from linear sweep voltammetry （LSV） is 7.9 mA·cm^-2,which is 1.4 and 5.2 times as high as those of the catalysts prepared by co-impregnation/NaBH4 and co-impregnation/ HCOOH reduction methods,2.1 times as high as that of the 10 wt.% Pt-WO3/C catalyst prepared by co-impregnation/EG method,respectively.展开更多
近年来,具有丰富活性中心的二维合金高效电催化剂的合成引起人们极大关注.本工作以十六烷基三甲基溴化铵和六羰基钼为结构导向剂合成出三金属钯-银-铜纳米片组装体.用高角度环形暗场扫描透射电子显微镜、透射电子显微镜和X射线衍射仪对...近年来,具有丰富活性中心的二维合金高效电催化剂的合成引起人们极大关注.本工作以十六烷基三甲基溴化铵和六羰基钼为结构导向剂合成出三金属钯-银-铜纳米片组装体.用高角度环形暗场扫描透射电子显微镜、透射电子显微镜和X射线衍射仪对三金属PdAgCu纳米片组装体的形貌和结构进行了表征.结果表明三金属Pd6Ag3Cu2纳米片组装体电催化性能优异,且对乙二醇氧化反应(5696 mA mgPd^(-1))和乙醇氧化反应(4374 mA mgPd^(-1))具有良好的催化稳定性.电催化活性的增强可归因于应变效应、配体效应及双功能效应的协同作用.本文系统研究了三金属电催化剂对C2醇的电催化机理,发现较高的羟基和C2醇浓度有利于乙二醇氧化反应和乙醇氧化反应.展开更多
We present a simple method to increase the efficiency of a direct ethanol fuel cell by a periodic modulation of the load(pulsed mode). The fuel cell was periodically short circuited with a resistor(1 Ω) for a few sec...We present a simple method to increase the efficiency of a direct ethanol fuel cell by a periodic modulation of the load(pulsed mode). The fuel cell was periodically short circuited with a resistor(1 Ω) for a few seconds(high load period) followed by a low load period of up to 100 s when the resistor was disconnected. The open circuit voltage(OCV) values before and after the short circuit of the cell showed an increase of up to 70 mV. The higher OCV was due to the oxidation and removal of strongly adsorbed CO during the electric short circuit when the electric potential of the anode was increased to be close to the cathode potential. The depoisoned anode surface was much more active directly after the short circuit. The slow decrease of the OCV observed after the short circuit was caused by the subsequent poisoning of the anode surface, which can be neutralized by another short circuit. In general, a stable increase in cell performance was obtained by repetition of the electric short circuit. The data showed that the pulse mode gave an increase in the power generated by the direct ethanol fuel cell by up to 51% and was 6% on average. It is anticipated that this mode of operation can be used also in different types of polymer electrolyte membrane fuel cells where CO poisoning is a problem, and after optimization of the parameters, a much higher gain in efficien-cy can be obtained.展开更多
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
基金supported by the National Basic Research and Development Program of China (No. 2009CB220100)Beijing Excellent Talent Support Program (No. 20071D1600300396)
文摘Three co-impregnation/chemical reduction methods in acidic solutions of pH 〈 1,including ethylene glycol （EG）,NaBH4,and HCOOH,were compared for Pt-WO3/C catalysts.Pt-WO3/C catalysts containing 10 wt.% and 20 wt.% platinum per carbon were prepared by the three methods; their morphology and electrocatalytic activities were characterized.The 20 wt.% Pt-WO3/C catalyst prepared by the co-impregnation/EG method presented the optimal dispersion with an average particle size of 4.6 nm and subsequently the best electrocatalytic activity,and so,it was further characterized.Its anodic peak current density for ethanol oxidation from linear sweep voltammetry （LSV） is 7.9 mA·cm^-2,which is 1.4 and 5.2 times as high as those of the catalysts prepared by co-impregnation/NaBH4 and co-impregnation/ HCOOH reduction methods,2.1 times as high as that of the 10 wt.% Pt-WO3/C catalyst prepared by co-impregnation/EG method,respectively.
基金supported by the National Natural Science Foundation of China(22172084 and 21773133)the World-Class Discipline Program of Shandong Province,China。
文摘近年来,具有丰富活性中心的二维合金高效电催化剂的合成引起人们极大关注.本工作以十六烷基三甲基溴化铵和六羰基钼为结构导向剂合成出三金属钯-银-铜纳米片组装体.用高角度环形暗场扫描透射电子显微镜、透射电子显微镜和X射线衍射仪对三金属PdAgCu纳米片组装体的形貌和结构进行了表征.结果表明三金属Pd6Ag3Cu2纳米片组装体电催化性能优异,且对乙二醇氧化反应(5696 mA mgPd^(-1))和乙醇氧化反应(4374 mA mgPd^(-1))具有良好的催化稳定性.电催化活性的增强可归因于应变效应、配体效应及双功能效应的协同作用.本文系统研究了三金属电催化剂对C2醇的电催化机理,发现较高的羟基和C2醇浓度有利于乙二醇氧化反应和乙醇氧化反应.
基金supported by the Ministry of Science and Higher Education (Poland) under the grant N N204 527739
文摘We present a simple method to increase the efficiency of a direct ethanol fuel cell by a periodic modulation of the load(pulsed mode). The fuel cell was periodically short circuited with a resistor(1 Ω) for a few seconds(high load period) followed by a low load period of up to 100 s when the resistor was disconnected. The open circuit voltage(OCV) values before and after the short circuit of the cell showed an increase of up to 70 mV. The higher OCV was due to the oxidation and removal of strongly adsorbed CO during the electric short circuit when the electric potential of the anode was increased to be close to the cathode potential. The depoisoned anode surface was much more active directly after the short circuit. The slow decrease of the OCV observed after the short circuit was caused by the subsequent poisoning of the anode surface, which can be neutralized by another short circuit. In general, a stable increase in cell performance was obtained by repetition of the electric short circuit. The data showed that the pulse mode gave an increase in the power generated by the direct ethanol fuel cell by up to 51% and was 6% on average. It is anticipated that this mode of operation can be used also in different types of polymer electrolyte membrane fuel cells where CO poisoning is a problem, and after optimization of the parameters, a much higher gain in efficien-cy can be obtained.
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.
