氧还原反应(ORR)是一个动力学缓慢的过程,而Pt或Pt基材料是其有效的电催化剂。本文通过构建合理的空间结构来大幅提高Pt的质量活性,并通过引入过渡金属共掺杂来提高Pt的本征活性,制备得到了Pt含量在4%(质量分数)以下的Pt-Co-Ni共掺杂的...氧还原反应(ORR)是一个动力学缓慢的过程,而Pt或Pt基材料是其有效的电催化剂。本文通过构建合理的空间结构来大幅提高Pt的质量活性,并通过引入过渡金属共掺杂来提高Pt的本征活性,制备得到了Pt含量在4%(质量分数)以下的Pt-Co-Ni共掺杂的空心碳球/管状碳复合催化剂Pt-Co-Ni/NHCS-TUC-600。ORR电化学活性测试表明,Pt-Co-Ni/NHCS-TUC-600在0.1 mol/LHClO_(4)中具有与商业Pt/C相当的起始电位(0.927 V vs RHE)和半波电位(0.867 V vs RHE),优于商业Pt/C的极限扩散电流密度(6.97 mA/cm^(2))。这些优异的ORR活性使得Pt-Co-Ni/NHCS-TUC-600具有广阔的应用前景,为低载量铂催化剂的研究与应用提供了新的可能。展开更多
MgO/Al2O3 and Fe2O3/MgO/Al2O3 solid bases were prepared through mixing method. After sulfonated cobalt phthalocyanine （CoPcS） being supported on these solid bases, the catalytic performance of these catalysts was ev...MgO/Al2O3 and Fe2O3/MgO/Al2O3 solid bases were prepared through mixing method. After sulfonated cobalt phthalocyanine （CoPcS） being supported on these solid bases, the catalytic performance of these catalysts was evaluated by means of mercaptan oxidation reaction. The samples were characterized by X-ray diffraction （XRD）, CO2 temperature-programmed desorption （CO2-TPD）, FTIR spectroscopy, and X-ray photoelectron spectroscopy （XPS）. Investigation was focused on the effect of Fe2O3 on activity, crystal structure, basicity, and stability of the catalyst and also on the role of Fe2O3 in the mercaptan oxidation processes. Test results have shown that the Fe2O3/MgO/Al2O3- CoPcS catalyst has a higher initial activity and a much longer service life than the MgO/Al2O3-CoPcS catalyst. The increased types of basic sites coupled with an enhanced oxidation ability resulted from the addition of Fe2O3 have contributed to the improvement of the catalytic activity of the MgO/Al2O3-CoPcS catalyst.展开更多
Using the ab initio plane-wave ultrasoft pseudopotential method based on generalized gradient approximation（GGA）,we investigated the band-gap tuning in monolayer phosphorene（MLP） and bilayer phosphorene（BLP） by ...Using the ab initio plane-wave ultrasoft pseudopotential method based on generalized gradient approximation（GGA）,we investigated the band-gap tuning in monolayer phosphorene（MLP） and bilayer phosphorene（BLP） by external electric fields applied perpendicular to the layers.The band continuously decreases with increasing applied electric fields,eventually rendering them metallic.For MLP,the phenomenon is explained in the light of the giant Stark effect,which is essentially characterized by the interlayer spacing,for the rate of change of bandgap with applied external field.The atomic distance and charges also contribute to the semiconductor-metal transition.The BLP is more sensitive to electric fields than MLP,since their charges are rearranged among bilayers and the bandgap can dramatically drop in terms of electronic field.The results show the bandgap will change for the fabrication of novel electronic and photonic devices.展开更多
The atomic and electronic structures of AB-stacking bilayer graphene(BLG)in the presence of H_(2)O molecules are investigated by density functional theory calculations.For free-standing BLG,the bandgap is opened to 0....The atomic and electronic structures of AB-stacking bilayer graphene(BLG)in the presence of H_(2)O molecules are investigated by density functional theory calculations.For free-standing BLG,the bandgap is opened to 0.101 eV with a single H_(2)O molecule adsorbed on its surface.The perfectly suspended BLG is sensitive to H_(2)O adsorbates,which break the BLG lattice symmetry and open an energy gap.While a single H_(2)O molecule is adsorbed on the BLG surface with a SiO2 substrate,the bandgap widens to 0.363 eV.Both the H_(2)O molecule adsorption and the oxide substrate contribute to the BLG bandgap opening.The phenomenon is interpreted with the charge transfer process in 2D carbon nanostructures.展开更多
The energetic and electronic structure of bilayered graphene(BLG)with AA stacking arrangement on a SiO_(2) substrate is investigated in the presence of an electric field F of different intensities by ab initio density...The energetic and electronic structure of bilayered graphene(BLG)with AA stacking arrangement on a SiO_(2) substrate is investigated in the presence of an electric field F of different intensities by ab initio density functional calculations.The AA−stacked bilayer graphene is stable on the SiO_(2) substrate in the absence of an electric field.However,as F increases,the AA-stacked bilayer graphenes are gradually shifted with each other and finally transfers into AB-stacked bilayer graphenes.The bandgap is accordingly changed.展开更多
文摘氧还原反应(ORR)是一个动力学缓慢的过程,而Pt或Pt基材料是其有效的电催化剂。本文通过构建合理的空间结构来大幅提高Pt的质量活性,并通过引入过渡金属共掺杂来提高Pt的本征活性,制备得到了Pt含量在4%(质量分数)以下的Pt-Co-Ni共掺杂的空心碳球/管状碳复合催化剂Pt-Co-Ni/NHCS-TUC-600。ORR电化学活性测试表明,Pt-Co-Ni/NHCS-TUC-600在0.1 mol/LHClO_(4)中具有与商业Pt/C相当的起始电位(0.927 V vs RHE)和半波电位(0.867 V vs RHE),优于商业Pt/C的极限扩散电流密度(6.97 mA/cm^(2))。这些优异的ORR活性使得Pt-Co-Ni/NHCS-TUC-600具有广阔的应用前景,为低载量铂催化剂的研究与应用提供了新的可能。
文摘MgO/Al2O3 and Fe2O3/MgO/Al2O3 solid bases were prepared through mixing method. After sulfonated cobalt phthalocyanine （CoPcS） being supported on these solid bases, the catalytic performance of these catalysts was evaluated by means of mercaptan oxidation reaction. The samples were characterized by X-ray diffraction （XRD）, CO2 temperature-programmed desorption （CO2-TPD）, FTIR spectroscopy, and X-ray photoelectron spectroscopy （XPS）. Investigation was focused on the effect of Fe2O3 on activity, crystal structure, basicity, and stability of the catalyst and also on the role of Fe2O3 in the mercaptan oxidation processes. Test results have shown that the Fe2O3/MgO/Al2O3- CoPcS catalyst has a higher initial activity and a much longer service life than the MgO/Al2O3-CoPcS catalyst. The increased types of basic sites coupled with an enhanced oxidation ability resulted from the addition of Fe2O3 have contributed to the improvement of the catalytic activity of the MgO/Al2O3-CoPcS catalyst.
基金Funded by National Natural Science Foundation of China(No.61176101)the PhD Programs Foundation of Ministry of Education of China(No.20120101120156)Key Laboratory of Nanodevices and Applications,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(No.14JG01)
文摘Using the ab initio plane-wave ultrasoft pseudopotential method based on generalized gradient approximation（GGA）,we investigated the band-gap tuning in monolayer phosphorene（MLP） and bilayer phosphorene（BLP） by external electric fields applied perpendicular to the layers.The band continuously decreases with increasing applied electric fields,eventually rendering them metallic.For MLP,the phenomenon is explained in the light of the giant Stark effect,which is essentially characterized by the interlayer spacing,for the rate of change of bandgap with applied external field.The atomic distance and charges also contribute to the semiconductor-metal transition.The BLP is more sensitive to electric fields than MLP,since their charges are rearranged among bilayers and the bandgap can dramatically drop in terms of electronic field.The results show the bandgap will change for the fabrication of novel electronic and photonic devices.
基金by the National Science Foundation(NSF)of USA(ECCS-1002228)and the National Science Foundation of China(61176101)the“Zi Jing Program Foundation”of Zhejiang University,the Zhejiang-Provincial Fund for Overseas Returneesthe Vice-Chancellor’s Postdoctoral Research Fellowship Program of the University of New South Wales(SIR50/PS19184).
文摘The atomic and electronic structures of AB-stacking bilayer graphene(BLG)in the presence of H_(2)O molecules are investigated by density functional theory calculations.For free-standing BLG,the bandgap is opened to 0.101 eV with a single H_(2)O molecule adsorbed on its surface.The perfectly suspended BLG is sensitive to H_(2)O adsorbates,which break the BLG lattice symmetry and open an energy gap.While a single H_(2)O molecule is adsorbed on the BLG surface with a SiO2 substrate,the bandgap widens to 0.363 eV.Both the H_(2)O molecule adsorption and the oxide substrate contribute to the BLG bandgap opening.The phenomenon is interpreted with the charge transfer process in 2D carbon nanostructures.
基金by the USA National Science Foundation(NSF)under Grant No ECCS-1002228the Zi Jing Program Foundation of Zhejiang University+1 种基金the 2010 Funding to the Researcher from Oversea by Zhejiang Provincethe Vice-Chancellor’s Postdoctoral Research Fellowship Program of the University of New South Wales(SIR50/PS19184).
文摘The energetic and electronic structure of bilayered graphene(BLG)with AA stacking arrangement on a SiO_(2) substrate is investigated in the presence of an electric field F of different intensities by ab initio density functional calculations.The AA−stacked bilayer graphene is stable on the SiO_(2) substrate in the absence of an electric field.However,as F increases,the AA-stacked bilayer graphenes are gradually shifted with each other and finally transfers into AB-stacked bilayer graphenes.The bandgap is accordingly changed.
