We prepared Co_(x)Pt_(100-x)(x=40,45,50,55,60)nanoparticles by the sol-gel method.The phase composition and crystal structure,morphology and microstructure,and magnetic properties of the samples were characterized and...We prepared Co_(x)Pt_(100-x)(x=40,45,50,55,60)nanoparticles by the sol-gel method.The phase composition and crystal structure,morphology and microstructure,and magnetic properties of the samples were characterized and tested using X-ray diffraction(XRD),transmission electron microscopy(TEM),and vibrating sample magnetometer(VSM),respectively.The results demonstrate that the coercivity of CoPt nanoparticles can be effectively controlled by adjusting the atomic ratio of Co and Pt in the samples.Among the compositions studied,the Co_(45)Pt_(55)sample synthesized by the sol-gel method exhibits smaller grain size and a coercivity as high as 6.65×10^(5) A/m is achieved.The morphology and microstructure of the nanoparticles were analyzed by TEM images,indicating that a slight excess of Pt can effectively enhance the coercivity of CoPt nanoparticles.展开更多
This study,a core-shell CoPt@C assembled hierarchical catalyst(named CoPt@C)was prepared using a unique CH_(4)deposition strategy for highly efficient overall water splitting.CoPt@C is composed of dense CoPt@C core-sh...This study,a core-shell CoPt@C assembled hierarchical catalyst(named CoPt@C)was prepared using a unique CH_(4)deposition strategy for highly efficient overall water splitting.CoPt@C is composed of dense CoPt@C core-shell nanoparticles(NPs)and a minor proportion of curled CoPt@nanotubes(CoPt@CNTs).Moreover,by adjusting the CH_(4)deposition time,the carbon shell thickness can be effectively regulated.Benefiting from the synergistic interaction between CoPt alloy and carbon shell,coupled with the high conductivity of the carbon shell,the overpotential of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)for CoPt@C is 15 and 120 mV at 10 mA cm^(-2).In addition,CoPt@C requires only 1.58 V to achieve 10 mA cm^(-2)for overall water splitting and maintains excellent stability over 80 h of continuous electrolysis.Density functional theory(DFT)calculations suggest that electrons transfer from the CoPt alloy NPs to the carbon shell,rendering the carbon shell electron-rich.Additionally,the hydrogen adsorption energy(ΔG*H)and the rate-determining step(ΔG*OOH)on CoPt@C are only-0.22 and 1.9 eV,respectively.展开更多
基金Funded by the National Natural Science Foundation of China(No.52371169)。
文摘We prepared Co_(x)Pt_(100-x)(x=40,45,50,55,60)nanoparticles by the sol-gel method.The phase composition and crystal structure,morphology and microstructure,and magnetic properties of the samples were characterized and tested using X-ray diffraction(XRD),transmission electron microscopy(TEM),and vibrating sample magnetometer(VSM),respectively.The results demonstrate that the coercivity of CoPt nanoparticles can be effectively controlled by adjusting the atomic ratio of Co and Pt in the samples.Among the compositions studied,the Co_(45)Pt_(55)sample synthesized by the sol-gel method exhibits smaller grain size and a coercivity as high as 6.65×10^(5) A/m is achieved.The morphology and microstructure of the nanoparticles were analyzed by TEM images,indicating that a slight excess of Pt can effectively enhance the coercivity of CoPt nanoparticles.
基金financially supported by the Natural Science Foundation of National(No.NSFC22208179)the Key Laboratory of Laser Technology and Optoelectronic Functional Materials of Hainan Province(No.2024LTOM05)
文摘This study,a core-shell CoPt@C assembled hierarchical catalyst(named CoPt@C)was prepared using a unique CH_(4)deposition strategy for highly efficient overall water splitting.CoPt@C is composed of dense CoPt@C core-shell nanoparticles(NPs)and a minor proportion of curled CoPt@nanotubes(CoPt@CNTs).Moreover,by adjusting the CH_(4)deposition time,the carbon shell thickness can be effectively regulated.Benefiting from the synergistic interaction between CoPt alloy and carbon shell,coupled with the high conductivity of the carbon shell,the overpotential of hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)for CoPt@C is 15 and 120 mV at 10 mA cm^(-2).In addition,CoPt@C requires only 1.58 V to achieve 10 mA cm^(-2)for overall water splitting and maintains excellent stability over 80 h of continuous electrolysis.Density functional theory(DFT)calculations suggest that electrons transfer from the CoPt alloy NPs to the carbon shell,rendering the carbon shell electron-rich.Additionally,the hydrogen adsorption energy(ΔG*H)and the rate-determining step(ΔG*OOH)on CoPt@C are only-0.22 and 1.9 eV,respectively.
