It was found for the first time that iron tetraphenylporphyrin (FeTPP)-Pt/C showed the good activity for the electroreduction of oxygen and methanol tolerant ability. Their perfor- mances were related to the heat-tre...It was found for the first time that iron tetraphenylporphyrin (FeTPP)-Pt/C showed the good activity for the electroreduction of oxygen and methanol tolerant ability. Their perfor- mances were related to the heat-treatment temperature.展开更多
It was reported for the first time that phosphorictungstenic acid （PWA） could promote the oxygen reduction reaction （ORR） and inhibit the methanol oxidation reaction at the cathodic Pt/C catalyst in the direct met...It was reported for the first time that phosphorictungstenic acid （PWA） could promote the oxygen reduction reaction （ORR） and inhibit the methanol oxidation reaction at the cathodic Pt/C catalyst in the direct methanol fuel cell （DMFC）. When the weight ratio of PWA to Pt/C is 1, the composite catalyst increases the reduction current of oxygen by about 38% and decreases the oxidation current of methanol by about 76% compared with that of the Pt/C catalyst.展开更多
The development of cost-effective oxygen reduction reaction （ORR） catalysts with a high methanol tolerance and enhanced durability is highly desirable for direct methanol fuel cells. This work focuses on the convers...The development of cost-effective oxygen reduction reaction （ORR） catalysts with a high methanol tolerance and enhanced durability is highly desirable for direct methanol fuel cells. This work focuses on the conversion of PtNi nanoparticles from a disordered solid solution to an ordered intermetallic compound. Here the effect of this conversion on ORR activity, durability, and methanol tolerance are characterized. X-ray diffraction and transmission electron microscopy results confirm the formation of ordered PtNi intermetallic nanoparticles with high dispersion and a mean particle size of about 7.6 nm. The PtNi intermetallic nanoparticles exhibited enhanced mass and specific activities toward the methanol-tolerant ORR in pure and methanol-containing electrolytes. The specific activity of the ORR at 0.85 V on the PtNi intermetallic nanoparticles is almost 6 times greater than on commercial Pt/C and 3 times greater than on disordered PtNi alloy. Durability tests indicated a minimal loss of ORR activity for PtNi intermetallic nanoparticles after 5,000 potential cycles, whereas the ORR activity decreased by 28% for disordered PtNi alloy. The enhanced methanoltolerant ORR activity and durability may be attributed to the structural and compositional stabilities of the ordered PtNi intermetallic nanoparticles compared relative to the stabilities of the disordered PtNi alloy, strongly suggesting that the PtNi intermetallic nanoparticles may serve as highly active and durable methanol-tolerant ORR electrocatalysts for practical applications.展开更多
The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction （ORR） is extremely important for accelerating the commercial viability of direct methanol fuel cells （DMFCs...The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction （ORR） is extremely important for accelerating the commercial viability of direct methanol fuel cells （DMFCs）. In this work, we present an efficient and template-free route for facile synthesis of cyanide （CN^-）-functionalized PtNi hollow nanospheres （PtNi@CN HNSs） with a high alloying degree using a simple cyanogel reduction method at room temperature. The physical and electrocatalytic properties of the PtNi@CN HNSs were investigated by various physical and electrochemical techniques. The PtNi@CN HNSs exhibited significantly enhanced electrocatalytic activity, durability, and particular methanol tolerance for the ORR as compared to commercial Pt black, and thus they are promising cathode electrocatalysts for DMFCs.展开更多
Development of high-performance oxygen reduction reaction （ORR） catalysts is crucial to improve proton exchange membrane fuel cells. Herein, a multicomponent nanoporous PdCuTiA1 （np-PdCuTiA1） electrocatalyst has b...Development of high-performance oxygen reduction reaction （ORR） catalysts is crucial to improve proton exchange membrane fuel cells. Herein, a multicomponent nanoporous PdCuTiA1 （np-PdCuTiA1） electrocatalyst has been synthesized by a facile one-step dealloying strategy. The np-PdCuTiA1 catalyst exhibits a three-dimensional bicontinuous interpenetrating ligament/channel structure with an ultrafine length scale of -3.7 nm. The half-wave potential of np PdCuTiA1 is 0.873 V vs. RHE, more positive than those of PdC （0.756 V vs. RHE） and PtC （0.864 V vs. RHE） catalysts. The np-PdCuTiAl alloy shows a 4-electron reaction pathway with similar Tafel slopes to PtC. Remarkably, the half-wave potential shows a negative shift of only 12 mV for np-PdCuTiA1 in the presence of methanol, and this negative shift is much lower than those of the PdC （50 mV） and PtC （165 mV） catalysts. The enhanced ORR activity of np-PdCuTiA1 has been further rationalized through density functional theory calculations.展开更多
Direct methanol fuel cells(DMFCs)have received extensive attention on their high efficiency,high reliability,and no carbon emission.Unfortunately,the poor methanol tolerance and sluggish oxygen reduction reaction(ORR)...Direct methanol fuel cells(DMFCs)have received extensive attention on their high efficiency,high reliability,and no carbon emission.Unfortunately,the poor methanol tolerance and sluggish oxygen reduction reaction(ORR)at cathode have seriously hindered their further development.Herein we report the synthesis of a new class of Rh-doped PdAg alloy nanoparticles(NPs)for boosting ORR activity with high methanol tolerance capacity concurrently.The ORR mass activity of typical Rh_4Pd_(40)Ag_(56)NPs is 4.2 times higher than that of commercial Pt catalyst.Moreover,it shows a great methanol tolerance capability by maintaining 92.4%in ORR mass activity in alkaline solution with 0.1 mol L^(à1)methanol,against a big decrease of almost 100%for commercial Pt.Even after 30,000 potential cycles with 1.0 mol L^(à1)methanol,Rh_4Pd_(40)Ag_(56)NPs still retain ORR mass activity of up to 68.3%.DFT calculations reveal that excellent ORR performance with excellent methanol tolerance originates the active d-band-pinning engineering for an efficient site-independent electron-transfer.A generalized d-band mediated fine electron-transfer tuning path has blueprinted for effectively minimizing intrinsic ORR barriers with high current density.The present work highlights the key role of Rh doping in enhancing the ORR activity and methanol tolerance ability of PdAg NPs for future high-performance DMFCs.展开更多
Although Pt-based catalysts have been considered as the most effective electrocatalyst for the cathodic oxygen reduction reaction(ORR) of direct methanol fuel cells(DMFCs), they still suffer from the drawbacks of high...Although Pt-based catalysts have been considered as the most effective electrocatalyst for the cathodic oxygen reduction reaction(ORR) of direct methanol fuel cells(DMFCs), they still suffer from the drawbacks of high cost, poor long-term stability and methanol/CO poisoning effects. Thus, developing low-cost ORR catalysts with high efficiency, durability and antipoisoning ability is of paramount importance. Herein, a series of non-noble metal FeNC materials are prepared through a facile pyrolysis process and used as the electrocatalysts toward ORR in alkaline electrolyte. Results show that the FeNC-800-1h catalyst pyrolyzed at 800 ℃ for 1 h with the mass ratio of Fe(NO)·6HO to melamine being 0.50 exhibits the highest catalytic performance among the as-prepared FeN C catalysts. The half-wave potential of ORR is ca. 0.81 V, which is only 38 m V lower than that on the noble metal Pt/C catalyst. Besides, it also displays higher stability and methanol tolerance than Pt/C. There is almost no change in the current during the chronoamperometric test when methanol is added in the electrolyte whereas significant decrease is found on Pt/C catalyst. This study of FeN C catalysts provides new insights on understanding the ORR mechanism and suggests a promising strategy to develop low-cost and highly efficient non-noble metal electrocatalysts for ORR.展开更多
基金the financial supports of 973 Program．National Science and Technology Commission (G2000026408)，863 ProgramNational Science and Technology Commission(20011AA320306)Natural Science Foundation、Jilin Province(20000510)．
文摘It was found for the first time that iron tetraphenylporphyrin (FeTPP)-Pt/C showed the good activity for the electroreduction of oxygen and methanol tolerant ability. Their perfor- mances were related to the heat-treatment temperature.
基金The authors are grateful for the financial supports of“973”Project(G2000026408)“863"Project of Science and Technology Ministry of China(2001 AA323060,2003AA517060)+3 种基金the National Natural Science Foundation of China(20373068,20433060)Foundation of Department of Science and Technology of Jiangsu Province(BG200302)Industrialization Foundation of Advanced Technique of Jiangsu Province(JH02-080)National“211”Key Project.
文摘It was reported for the first time that phosphorictungstenic acid （PWA） could promote the oxygen reduction reaction （ORR） and inhibit the methanol oxidation reaction at the cathodic Pt/C catalyst in the direct methanol fuel cell （DMFC）. When the weight ratio of PWA to Pt/C is 1, the composite catalyst increases the reduction current of oxygen by about 38% and decreases the oxidation current of methanol by about 76% compared with that of the Pt/C catalyst.
文摘The development of cost-effective oxygen reduction reaction （ORR） catalysts with a high methanol tolerance and enhanced durability is highly desirable for direct methanol fuel cells. This work focuses on the conversion of PtNi nanoparticles from a disordered solid solution to an ordered intermetallic compound. Here the effect of this conversion on ORR activity, durability, and methanol tolerance are characterized. X-ray diffraction and transmission electron microscopy results confirm the formation of ordered PtNi intermetallic nanoparticles with high dispersion and a mean particle size of about 7.6 nm. The PtNi intermetallic nanoparticles exhibited enhanced mass and specific activities toward the methanol-tolerant ORR in pure and methanol-containing electrolytes. The specific activity of the ORR at 0.85 V on the PtNi intermetallic nanoparticles is almost 6 times greater than on commercial Pt/C and 3 times greater than on disordered PtNi alloy. Durability tests indicated a minimal loss of ORR activity for PtNi intermetallic nanoparticles after 5,000 potential cycles, whereas the ORR activity decreased by 28% for disordered PtNi alloy. The enhanced methanoltolerant ORR activity and durability may be attributed to the structural and compositional stabilities of the ordered PtNi intermetallic nanoparticles compared relative to the stabilities of the disordered PtNi alloy, strongly suggesting that the PtNi intermetallic nanoparticles may serve as highly active and durable methanol-tolerant ORR electrocatalysts for practical applications.
基金This research was sponsored by National Natural Science Foundation of China （Nos. 21473111 and 21376122）, Natural Science Foundation of Shaanxi Province （No. 2015JM2043）, and Fundamental Research Funds for the Central Universities （No. GK201602002）.
文摘The development of active and methanol-tolerant cathode electrocatalysts for the oxygen reduction reaction （ORR） is extremely important for accelerating the commercial viability of direct methanol fuel cells （DMFCs）. In this work, we present an efficient and template-free route for facile synthesis of cyanide （CN^-）-functionalized PtNi hollow nanospheres （PtNi@CN HNSs） with a high alloying degree using a simple cyanogel reduction method at room temperature. The physical and electrocatalytic properties of the PtNi@CN HNSs were investigated by various physical and electrochemical techniques. The PtNi@CN HNSs exhibited significantly enhanced electrocatalytic activity, durability, and particular methanol tolerance for the ORR as compared to commercial Pt black, and thus they are promising cathode electrocatalysts for DMFCs.
文摘Development of high-performance oxygen reduction reaction （ORR） catalysts is crucial to improve proton exchange membrane fuel cells. Herein, a multicomponent nanoporous PdCuTiA1 （np-PdCuTiA1） electrocatalyst has been synthesized by a facile one-step dealloying strategy. The np-PdCuTiA1 catalyst exhibits a three-dimensional bicontinuous interpenetrating ligament/channel structure with an ultrafine length scale of -3.7 nm. The half-wave potential of np PdCuTiA1 is 0.873 V vs. RHE, more positive than those of PdC （0.756 V vs. RHE） and PtC （0.864 V vs. RHE） catalysts. The np-PdCuTiAl alloy shows a 4-electron reaction pathway with similar Tafel slopes to PtC. Remarkably, the half-wave potential shows a negative shift of only 12 mV for np-PdCuTiA1 in the presence of methanol, and this negative shift is much lower than those of the PdC （50 mV） and PtC （165 mV） catalysts. The enhanced ORR activity of np-PdCuTiA1 has been further rationalized through density functional theory calculations.
基金financially supported by the National Natural Science Foundation of China (NSFC) (51671003)National Basic Research Program of China (2017YFA0206701)+3 种基金the China Postdoctoral Science Foundation (2017M620526 and 2017M620518)Open Project Foundation of State Key Laboratory of Chemical Resource Engineeringthe Start-up Supports from Peking University and Young Thousand Talented Program, and Early Career Scheme (ECS)fund (PolyU 253026/16P) from the Research Grant Council (RGC) in Hong Kong
文摘Direct methanol fuel cells(DMFCs)have received extensive attention on their high efficiency,high reliability,and no carbon emission.Unfortunately,the poor methanol tolerance and sluggish oxygen reduction reaction(ORR)at cathode have seriously hindered their further development.Herein we report the synthesis of a new class of Rh-doped PdAg alloy nanoparticles(NPs)for boosting ORR activity with high methanol tolerance capacity concurrently.The ORR mass activity of typical Rh_4Pd_(40)Ag_(56)NPs is 4.2 times higher than that of commercial Pt catalyst.Moreover,it shows a great methanol tolerance capability by maintaining 92.4%in ORR mass activity in alkaline solution with 0.1 mol L^(à1)methanol,against a big decrease of almost 100%for commercial Pt.Even after 30,000 potential cycles with 1.0 mol L^(à1)methanol,Rh_4Pd_(40)Ag_(56)NPs still retain ORR mass activity of up to 68.3%.DFT calculations reveal that excellent ORR performance with excellent methanol tolerance originates the active d-band-pinning engineering for an efficient site-independent electron-transfer.A generalized d-band mediated fine electron-transfer tuning path has blueprinted for effectively minimizing intrinsic ORR barriers with high current density.The present work highlights the key role of Rh doping in enhancing the ORR activity and methanol tolerance ability of PdAg NPs for future high-performance DMFCs.
基金supported by the National Natural Science Foundation of China(22072070)the Natural Science Foundation of Shandong Province(ZR2019MB036)。
文摘Although Pt-based catalysts have been considered as the most effective electrocatalyst for the cathodic oxygen reduction reaction(ORR) of direct methanol fuel cells(DMFCs), they still suffer from the drawbacks of high cost, poor long-term stability and methanol/CO poisoning effects. Thus, developing low-cost ORR catalysts with high efficiency, durability and antipoisoning ability is of paramount importance. Herein, a series of non-noble metal FeNC materials are prepared through a facile pyrolysis process and used as the electrocatalysts toward ORR in alkaline electrolyte. Results show that the FeNC-800-1h catalyst pyrolyzed at 800 ℃ for 1 h with the mass ratio of Fe(NO)·6HO to melamine being 0.50 exhibits the highest catalytic performance among the as-prepared FeN C catalysts. The half-wave potential of ORR is ca. 0.81 V, which is only 38 m V lower than that on the noble metal Pt/C catalyst. Besides, it also displays higher stability and methanol tolerance than Pt/C. There is almost no change in the current during the chronoamperometric test when methanol is added in the electrolyte whereas significant decrease is found on Pt/C catalyst. This study of FeN C catalysts provides new insights on understanding the ORR mechanism and suggests a promising strategy to develop low-cost and highly efficient non-noble metal electrocatalysts for ORR.
