Superior catalyst supports are crucial to developing advanced electrocatalysts toward heterogeneous catalytic reactions.Herein,we systematically investigate the role of transition metal‐functionalized N‐doped carbon...Superior catalyst supports are crucial to developing advanced electrocatalysts toward heterogeneous catalytic reactions.Herein,we systematically investigate the role of transition metal‐functionalized N‐doped carbon nanosheets(M‐N‐C,M=Mn,Fe,Co,Ni,Cu,Mo,and Ag)as the multifunctional electrocatalyst supports toward hydrogen evolution/oxidation reactions(HER/HOR)in alkaline media.The results demonstrate that all the M‐N‐C nanosheets,except Cu‐N‐C and Ag‐N‐C,can promote the alkaline HER/HOR electrocatalytic activity of Pt by accelerating the sluggish Volmer step,among which Mn plays a more significant role.Analyses reveal that the promotion effect of M‐N‐C support is closely associated with the electronegativity of the metal dopants and the relative filling degree of their d‐orbitals.For one,the metal dopant in M‐N‐C with smaller electronegativity would provide more electrons to oxygen and hence tune the electronic structure of Pt via the M‐O‐Pt bonds at the interface.For another,the transition metal in M‐N4 moieties with more empty d orbitals would hybridize with O 2p orbitals more strongly that promotes the adsorption of water/hydroxyl species.The results demonstrate the conceptual significance of multifunctional supports and would inspire the future development of advanced electrocatalysts.展开更多
Two-dimensional(2D)heterostructures based on layered transition metal dichalcogenides(TMDs)have attracted increasing attention for the applications of the nextgeneration high-performance integrated electronics and opt...Two-dimensional(2D)heterostructures based on layered transition metal dichalcogenides(TMDs)have attracted increasing attention for the applications of the nextgeneration high-performance integrated electronics and optoelectronics.Although various TMD heterostructures have been successfully fabricated,epitaxial growth of such atomically thin metal-semiconductor heterostructures with a clean and sharp interface is still challenging.In addition,photodetectors based on such heterostructures have seldom been studied.Here,we report the synthesis of high-quality vertical NbS2/MoS2metallic-semiconductor heterostructures.By using NbS2as the contact electrodes,the field-effect mobility and current on-off ratio of MoS2can be improved at least 6-fold and two orders of magnitude compared with the conventional Ti/Au contact,respectively.By using NbS2as contact,the photodetector performance of MoS2is much improved with higher responsivity and less response time.Such facile synthesis of atomically thin metal-semiconductor heterostructures by a simple chemical vapor deposition strategy and its effectiveness as ultrathin 2D metal contact open the door for the future application of electronics and optoelectronics.展开更多
文摘Superior catalyst supports are crucial to developing advanced electrocatalysts toward heterogeneous catalytic reactions.Herein,we systematically investigate the role of transition metal‐functionalized N‐doped carbon nanosheets(M‐N‐C,M=Mn,Fe,Co,Ni,Cu,Mo,and Ag)as the multifunctional electrocatalyst supports toward hydrogen evolution/oxidation reactions(HER/HOR)in alkaline media.The results demonstrate that all the M‐N‐C nanosheets,except Cu‐N‐C and Ag‐N‐C,can promote the alkaline HER/HOR electrocatalytic activity of Pt by accelerating the sluggish Volmer step,among which Mn plays a more significant role.Analyses reveal that the promotion effect of M‐N‐C support is closely associated with the electronegativity of the metal dopants and the relative filling degree of their d‐orbitals.For one,the metal dopant in M‐N‐C with smaller electronegativity would provide more electrons to oxygen and hence tune the electronic structure of Pt via the M‐O‐Pt bonds at the interface.For another,the transition metal in M‐N4 moieties with more empty d orbitals would hybridize with O 2p orbitals more strongly that promotes the adsorption of water/hydroxyl species.The results demonstrate the conceptual significance of multifunctional supports and would inspire the future development of advanced electrocatalysts.
基金financially supported by the National Key R&D Program of China(2018YFA0306900 and 2018YFA0305800)the National Natural Science Foundation of China(51872012)。
文摘Two-dimensional(2D)heterostructures based on layered transition metal dichalcogenides(TMDs)have attracted increasing attention for the applications of the nextgeneration high-performance integrated electronics and optoelectronics.Although various TMD heterostructures have been successfully fabricated,epitaxial growth of such atomically thin metal-semiconductor heterostructures with a clean and sharp interface is still challenging.In addition,photodetectors based on such heterostructures have seldom been studied.Here,we report the synthesis of high-quality vertical NbS2/MoS2metallic-semiconductor heterostructures.By using NbS2as the contact electrodes,the field-effect mobility and current on-off ratio of MoS2can be improved at least 6-fold and two orders of magnitude compared with the conventional Ti/Au contact,respectively.By using NbS2as contact,the photodetector performance of MoS2is much improved with higher responsivity and less response time.Such facile synthesis of atomically thin metal-semiconductor heterostructures by a simple chemical vapor deposition strategy and its effectiveness as ultrathin 2D metal contact open the door for the future application of electronics and optoelectronics.
