采用沉淀法制备铁掺杂镍碳酸盐纳米球前驱体,并对其进行硒化处理,得到性能优异的铁掺杂的氧化镍和硒化镍的混合物(Fe-NiO/NiSe2)电催化剂。利用XRD、XPS、TEM、FESEM等手段对材料的结构和组成进行表征,并对其进行了电化学性能测试。结...采用沉淀法制备铁掺杂镍碳酸盐纳米球前驱体,并对其进行硒化处理,得到性能优异的铁掺杂的氧化镍和硒化镍的混合物(Fe-NiO/NiSe2)电催化剂。利用XRD、XPS、TEM、FESEM等手段对材料的结构和组成进行表征,并对其进行了电化学性能测试。结果表明,Fe-NiO/NiSe2电催化剂材料具有优异的析氧性能,在1. 0 mol/L KOH电解液中,在10 m A/cm^2电流密度下所需过电势仅为323 m V,并具有显著的长期稳定性,作为析氧反应催化剂具有很好的应用前景。展开更多
A prerequisite for widespread applications of atomically thin transition metal dichalcogenides in future electronics is to achieve reliable electrical contacts,which is of considerable challenge due to the difficultie...A prerequisite for widespread applications of atomically thin transition metal dichalcogenides in future electronics is to achieve reliable electrical contacts,which is of considerable challenge due to the difficulties in selectively doping and inevitable physical damages of these atomically thin materials during typical metal integration process.Here,we report the in situ growth of ultrathin metallic NiSe single crystals on WSe2 in which the metallic NiSe nanosheets function as the contact electrodes to WSe2,creating an interface that is essentially free from chemical disorder.The NiSe/WSe2 heterostructures also exhibit well-aligned lattice orientation between the two layers,forming a periodic Moire pattern.Electrical transport studies demonstrate that the NiSe nanosheets exhibit an excellent metallic feature,as evidenced by the extra-high electrical conductivity of up to 1.6×10^6 S-nf1.The WSe2 transistors with the NiSe contact show field-effect mobilities (/vFe) more than double that with Cr/Au electrodes.This study demonstrates an effective pathway to achieve reliable electrical contacts to the atomically thin 2D materials,and maybe readily extended for fabricating 2D/2D low-resistance contacts for a variety of transition metal dichalcogenides.展开更多
Although nickel-based catalysts display good catalytic capability and excellent corrosion resistance under alkaline electrolytes for water splitting,it is still imperative to enhance their activity for real device app...Although nickel-based catalysts display good catalytic capability and excellent corrosion resistance under alkaline electrolytes for water splitting,it is still imperative to enhance their activity for real device applications.Herein,we decorated Ni0.85Se hollow nanospheres onto reduced graphene oxide(RGO)through a hydrothermal route,then annealed this composite at different temperatures(400℃,NiSe2-400 and 450℃,NiSe2-450)under argon atmosphere,yielding a kind of NiSe2/RGO composite catalysts.Positron annihilation spectra revealed two types of vacancies formed in this composite catalyst.We found that the NiSe2-400 catalyst with dual Ni-Se vacancies is able to catalyze the oxygen evolution reaction(OER)efficiently,needing a mere 241 mV overpotential at 10 mA·cm−2.In addition,this catalyst exhibits outstanding stability.Computational studies show favorable energy barrier on NiSe2-400,enabling moderate OH−adsorption and O2 desorption,which leads to the enhanced energetics for OER.展开更多
文摘采用沉淀法制备铁掺杂镍碳酸盐纳米球前驱体,并对其进行硒化处理,得到性能优异的铁掺杂的氧化镍和硒化镍的混合物(Fe-NiO/NiSe2)电催化剂。利用XRD、XPS、TEM、FESEM等手段对材料的结构和组成进行表征,并对其进行了电化学性能测试。结果表明,Fe-NiO/NiSe2电催化剂材料具有优异的析氧性能,在1. 0 mol/L KOH电解液中,在10 m A/cm^2电流密度下所需过电势仅为323 m V,并具有显著的长期稳定性,作为析氧反应催化剂具有很好的应用前景。
基金the financial support from the Fundamental Research Funds of the Central Universities (No.531107051078)the Double First-Class University In让iative of Hunan University (No.531109100004)+2 种基金the 111 Project of China (No.D17003)the support from the National Natural Science Foundation of China (No.751214296,51802090,61874041,and 61804050)Hunan Key Laboratory of Two-Dimensional Materials (No.801200005).
文摘A prerequisite for widespread applications of atomically thin transition metal dichalcogenides in future electronics is to achieve reliable electrical contacts,which is of considerable challenge due to the difficulties in selectively doping and inevitable physical damages of these atomically thin materials during typical metal integration process.Here,we report the in situ growth of ultrathin metallic NiSe single crystals on WSe2 in which the metallic NiSe nanosheets function as the contact electrodes to WSe2,creating an interface that is essentially free from chemical disorder.The NiSe/WSe2 heterostructures also exhibit well-aligned lattice orientation between the two layers,forming a periodic Moire pattern.Electrical transport studies demonstrate that the NiSe nanosheets exhibit an excellent metallic feature,as evidenced by the extra-high electrical conductivity of up to 1.6×10^6 S-nf1.The WSe2 transistors with the NiSe contact show field-effect mobilities (/vFe) more than double that with Cr/Au electrodes.This study demonstrates an effective pathway to achieve reliable electrical contacts to the atomically thin 2D materials,and maybe readily extended for fabricating 2D/2D low-resistance contacts for a variety of transition metal dichalcogenides.
基金We acknowledge financial support from the Tianjin science and technology support key projects(No.18YFZCSF00500)the National Natural Science Foundation of China(Nos.21521001,21431006,21225315,21321002,91645202,51702312,and 21975237)+6 种基金the Users with Excellence and Scientific Research Grant of Hefei Science Center of CAS(No.2015HSCUE007)the Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-SLH036)the National Basic Research Program of China(Nos.2014CB931800 and 2018YFA0702001)the Chinese Academy of Sciences(Nos.KGZD-EW-T05 and XDA090301001)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21000000)the Fundamental Research Funds for the Central Universities(No.WK2340000076)the Recruitment Program of Global Youth Experts.
文摘Although nickel-based catalysts display good catalytic capability and excellent corrosion resistance under alkaline electrolytes for water splitting,it is still imperative to enhance their activity for real device applications.Herein,we decorated Ni0.85Se hollow nanospheres onto reduced graphene oxide(RGO)through a hydrothermal route,then annealed this composite at different temperatures(400℃,NiSe2-400 and 450℃,NiSe2-450)under argon atmosphere,yielding a kind of NiSe2/RGO composite catalysts.Positron annihilation spectra revealed two types of vacancies formed in this composite catalyst.We found that the NiSe2-400 catalyst with dual Ni-Se vacancies is able to catalyze the oxygen evolution reaction(OER)efficiently,needing a mere 241 mV overpotential at 10 mA·cm−2.In addition,this catalyst exhibits outstanding stability.Computational studies show favorable energy barrier on NiSe2-400,enabling moderate OH−adsorption and O2 desorption,which leads to the enhanced energetics for OER.
