Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in...Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst （0.20 A/mgPt）. Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.展开更多
In this work,we demonstrated the enhanced oxygen evolution reaction（OER） activity of flower-shaped cobalt-nickel oxide（NiCo_2O_4） decorated with iridium-nickel bimetal as an electrode material.The samples were pre...In this work,we demonstrated the enhanced oxygen evolution reaction（OER） activity of flower-shaped cobalt-nickel oxide（NiCo_2O_4） decorated with iridium-nickel bimetal as an electrode material.The samples were prepared by carefully depositing pre-synthesized IrNi nanopartides on the surfaces of the NiCo_2O_4 nano-flowers.Compared with bare NiCo_2O_4,IrNi,and IrNi/Co_3O_4,the IrNi/NiCo_2O_4 exhibited significantly enhanced electrocatalytic activity in the OER,including a lower overpotential of 210 mV and a higher current density at an overpotential of 540 mV.We found that the IrNi/NiCo_2O_4 showed more efficient electron transport behavior and reduced polarization because of its bimetal IrNi modification by analyzing its Tafel slope and turnover frequency.Furthermore,the electrocatalytic mechanism of IrNi/NiCo_2O_4 in the OER was studied,and it was found that the combined active sites of the composite effectively improved the rate determining step.The synergic effect of the bimetal and metal oxide plays an important role in this reaction,enhancing the transmission efficiency of electrons and providing more active sites for the OER.The results reveal that IrNi/NiCo_2O_4 is an excellent electrocatalyst for OER.展开更多
基金This work is supported by Collaborative Innovation Center of Suzhou Nano Science and Technology, Ministry of Science and Technology of China （No.2014CB932700）, the National Natural Science Foundation of China （No.21603208, No.21573206, and No.51371164）, the China Postdoctoral Science Foundation （No.2015M580536, No.2016T90569）, Key Research Program of Frontier Sciences, CAS （QYZDBSSW- SLH017）, Strategic Priority Research Program B of the CAS （No.XDB01020000）, Hefei Science Center, CAS （No.2015HSC-UP016）, and Fundamental Research Funds for the Central Universities.
文摘Pt-based nanoframes represent a class of promising catalysts towards oxygen reduction reaction. Herein, we, for the first time, successfully prepared Pt-Pd octahedral nanoframes with ultrathin ridges less than 2 nm in thickness. The Pt-Pd octahedral nanoframes were obtained through site-selected deposition of Pt atoms onto the edge sites of Pd octahedral seeds, followed by selective removal of the Pd octahedral cores via chemical etching. Due to that a combination of three-dimensional opens geometrical structure and Pt-skin surface compositional structure, the Pt-Pd octahedral nanoframes/C catalyst shows a mass activity of 1.15 A/mgPt towards oxygen reduction reaction, 5.8 times enhancement in mass activity relative to commercial Pt/C catalyst （0.20 A/mgPt）. Moreover, even after 8000 cycles of accelerated durability test, the Pt-Pd octahedral nanoframes/C catalyst still exhibits a mass activity which is more than three times higher than that of pristine Pt/C catalyst.
基金supported by the National Natural Science Foundation of China(61371021 and 61671284)the support of Shanghai Education Commission(Peak Discipline Construction)
文摘In this work,we demonstrated the enhanced oxygen evolution reaction（OER） activity of flower-shaped cobalt-nickel oxide（NiCo_2O_4） decorated with iridium-nickel bimetal as an electrode material.The samples were prepared by carefully depositing pre-synthesized IrNi nanopartides on the surfaces of the NiCo_2O_4 nano-flowers.Compared with bare NiCo_2O_4,IrNi,and IrNi/Co_3O_4,the IrNi/NiCo_2O_4 exhibited significantly enhanced electrocatalytic activity in the OER,including a lower overpotential of 210 mV and a higher current density at an overpotential of 540 mV.We found that the IrNi/NiCo_2O_4 showed more efficient electron transport behavior and reduced polarization because of its bimetal IrNi modification by analyzing its Tafel slope and turnover frequency.Furthermore,the electrocatalytic mechanism of IrNi/NiCo_2O_4 in the OER was studied,and it was found that the combined active sites of the composite effectively improved the rate determining step.The synergic effect of the bimetal and metal oxide plays an important role in this reaction,enhancing the transmission efficiency of electrons and providing more active sites for the OER.The results reveal that IrNi/NiCo_2O_4 is an excellent electrocatalyst for OER.
