In this study, the effect of reduced graphene oxide(rGO) on interconnected Co_3O_4 nanosheets and the improved supercapacitive behaviors is reported. By optimizing the experimental parameters, we achieved a specific c...In this study, the effect of reduced graphene oxide(rGO) on interconnected Co_3O_4 nanosheets and the improved supercapacitive behaviors is reported. By optimizing the experimental parameters, we achieved a specific capacitance of ~1016.4 F g^(-1) for the Co_3O_4/rGO/NF(nickel foam) system at a current density of 1 A g^(-1). However, the Co_3O_4/NF structure without rGO only delivers a specific capacitance of ~520.0 F g^(-1)at the same current density. The stability test demonstrates that Co_3O_4/rGO/NF retains ~95.5% of the initial capacitance value even after 3000 charge–discharge cycles at a high current density of 7 A g^(-1). Further investigation reveals that capacitance improvement for the Co_3O_4/rGO/NF structure is mainly because of a higher specific surface area(~87.8 m^2g^(-1))and a more optimal mesoporous size(4–15 nm) compared to the corresponding values of 67.1 m^2g^(-1) and 6–25 nm,respectively, for the Co_3O_4/NF structure. rGO and the thinner Co_3O_4 nanosheets benefit from the strain relaxation during the charge and discharge processes, improving the cycling stability of Co_3O_4/rGO/NF.展开更多
A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomat...A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH4 oxidation in alkaline solution. The morphology and phase composition of PtCo/C0304 NSs are characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy （XPS）. The catalytic performance of PtCo/Co3O4 NSs is investigated by cyclic voltammetry （CV） and chronoamperometry （CA） in a standard three-electrode system. Current densities of 70 and 850 mA·cm^-2 were obtained at -0.4 V for Co/Co3O4 and PtCo/Co3O4 NSs, respectively, in a solution containing 2 mol·L^-1 NaOH and 0.2 mol·L^-1 NaBH4. The use of a noble metal （Pt） greatly enhances the catalytic activity of the transition metal （Co） and Co3O4. Besides, both Co and Co3O4 exhibit good B-H bond breaking ability （in NaBH4）, which leads to better electrocatalytic activity and stability of PtCo/Co3O4 NSs in NaBH4 electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co3O4 NSs can be a promising electrocatalyst for borohydride oxidation.展开更多
基金financially supported by the Key Research and Development Program of Hubei Province(2020BCA079)the National Natural Science Foundation of China(52173106)。
基金financially supported from the National Natural Science Foundation of China (Grant Nos.: 61376068, 11304132, 11304133, and 11405144)the Specialized Research Fund of the Doctoral Program of Higher Education (Grant Nos.: 20120211120003 and 20130211120009)the Fundamental Research Funds for the Central Universities (Grant Nos.: lzujbky2013-36 and lzujbky-2014-30)
文摘In this study, the effect of reduced graphene oxide(rGO) on interconnected Co_3O_4 nanosheets and the improved supercapacitive behaviors is reported. By optimizing the experimental parameters, we achieved a specific capacitance of ~1016.4 F g^(-1) for the Co_3O_4/rGO/NF(nickel foam) system at a current density of 1 A g^(-1). However, the Co_3O_4/NF structure without rGO only delivers a specific capacitance of ~520.0 F g^(-1)at the same current density. The stability test demonstrates that Co_3O_4/rGO/NF retains ~95.5% of the initial capacitance value even after 3000 charge–discharge cycles at a high current density of 7 A g^(-1). Further investigation reveals that capacitance improvement for the Co_3O_4/rGO/NF structure is mainly because of a higher specific surface area(~87.8 m^2g^(-1))and a more optimal mesoporous size(4–15 nm) compared to the corresponding values of 67.1 m^2g^(-1) and 6–25 nm,respectively, for the Co_3O_4/NF structure. rGO and the thinner Co_3O_4 nanosheets benefit from the strain relaxation during the charge and discharge processes, improving the cycling stability of Co_3O_4/rGO/NF.
基金We gratefully acknowledge the financial support of this research by the National Natural Science Foundation of China （No. 51572052）, the Natural Science Foundation of Heilongjiang Province of China （No. LC2015004）, the China Postdoctoral Science Special Foundation （No. 2015T80329）, the Major Project of Science and Technology of Heilongjiang Province （No. GA14A101） and the Project of Research and Development of Applied Technology of Harbin （No. 2014DB4AG016）.
文摘A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH4 oxidation in alkaline solution. The morphology and phase composition of PtCo/C0304 NSs are characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy （XPS）. The catalytic performance of PtCo/Co3O4 NSs is investigated by cyclic voltammetry （CV） and chronoamperometry （CA） in a standard three-electrode system. Current densities of 70 and 850 mA·cm^-2 were obtained at -0.4 V for Co/Co3O4 and PtCo/Co3O4 NSs, respectively, in a solution containing 2 mol·L^-1 NaOH and 0.2 mol·L^-1 NaBH4. The use of a noble metal （Pt） greatly enhances the catalytic activity of the transition metal （Co） and Co3O4. Besides, both Co and Co3O4 exhibit good B-H bond breaking ability （in NaBH4）, which leads to better electrocatalytic activity and stability of PtCo/Co3O4 NSs in NaBH4 electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co3O4 NSs can be a promising electrocatalyst for borohydride oxidation.
