Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performa...Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performance relying on specific nanostructures and electronic configurations.Herein,nickel was introduced as the dopant into one-dimensional (1D) hierarchical Co4N structures,achieving effective electronic regulation of Co4N toward high OER performance.The amount of Co3+increased after Ni-doping,and the in-situ formed surface oxyhydroxide during OER enhanced the electrocatalytic kinetics.Meanwhile,the 1D hierarchical structure further promoted the performances of Co4N owing to the high electrical conductivity and abundant activesites on the rough surface.As expected,the optimal Ni-doped Co4N with a Ni/Co molar ratio of 0.25 provides a small overpotential of 233 mV at a current density of 10 mA cm^(-2),with a low Tafel slope of 61 mV dec^(-1),and high long-term stability in 1.0 mol L^(-1)KOH.Following these results,the enhancement by doping the Co4N nanowire bundles with Fe and Cu was further evidenced for the OER.展开更多
A single-wall carbon nanotube(SWCNT)has superior optical,electrical,and mechanical properties due to its unique structure and is therefore expected to be able to form flexible high-performance transparent conductive f...A single-wall carbon nanotube(SWCNT)has superior optical,electrical,and mechanical properties due to its unique structure and is therefore expected to be able to form flexible high-performance transparent conductive films(TCFs).However,the optoelectronic performance of these films needs to be improved to meet the requirements of many devices.The electrical resistivity of SWCNTTCFs is mainly determined by the intrinsic resistivity of individual SWCNTs and their junction resistance in networks.We analyze these key factors and focus on the optimization of SWCNTs and their networks,which include the diameter,length,crystallinity and electrical type of the SWCNTs,and the bundle size and interconnects in networks,as well as chemical doping and microgrid design.We conclude that isolated/small-bundle,heavily doped metallic or semiconducting SWCNTs with a large diameter,long length and high crystallinity are necessary to fabricate high-performance SWCNTTCFs.A simple,controllable way to construct macroscopic SWCNT networks with Y-type connections,welded junctions or microgrid design is important in achieving a low resistivity.Finally,some insights into the key challenges in the manufacture and use of SWCNT TCFs and their prospects are presented,hoping to shed light on promoting the practical application of SWCNT TCFs in future flexible and stretchable optoelectronics.展开更多
基金financial support from China Postdoctoral Science Foundation (2020M673056)the National Key Research and Development Program of China (2018YFA0209402)the National Natural Science Foundation of China (21773093)。
文摘Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER).As a promising candidate,metallic Co4N already demonstrated electrocatalytic performance relying on specific nanostructures and electronic configurations.Herein,nickel was introduced as the dopant into one-dimensional (1D) hierarchical Co4N structures,achieving effective electronic regulation of Co4N toward high OER performance.The amount of Co3+increased after Ni-doping,and the in-situ formed surface oxyhydroxide during OER enhanced the electrocatalytic kinetics.Meanwhile,the 1D hierarchical structure further promoted the performances of Co4N owing to the high electrical conductivity and abundant activesites on the rough surface.As expected,the optimal Ni-doped Co4N with a Ni/Co molar ratio of 0.25 provides a small overpotential of 233 mV at a current density of 10 mA cm^(-2),with a low Tafel slope of 61 mV dec^(-1),and high long-term stability in 1.0 mol L^(-1)KOH.Following these results,the enhancement by doping the Co4N nanowire bundles with Fe and Cu was further evidenced for the OER.
基金National Natural Science Foundation of China(20966006)The Graduate Student Scientific Research Innovation Projects of the Inner Mongolia Autonomous Region(B20151012809)
基金financially supported by the Ministry of Science and Technology of China (Grant No.2016YFA0200101)the National Natural Science Foundation of China (Grant Nos.51625203,51532008,51572264,51772303,51761135122, 51872293)the Chinese Academy of Sciences (Grant No. 174321KYSB20160011)
文摘A single-wall carbon nanotube(SWCNT)has superior optical,electrical,and mechanical properties due to its unique structure and is therefore expected to be able to form flexible high-performance transparent conductive films(TCFs).However,the optoelectronic performance of these films needs to be improved to meet the requirements of many devices.The electrical resistivity of SWCNTTCFs is mainly determined by the intrinsic resistivity of individual SWCNTs and their junction resistance in networks.We analyze these key factors and focus on the optimization of SWCNTs and their networks,which include the diameter,length,crystallinity and electrical type of the SWCNTs,and the bundle size and interconnects in networks,as well as chemical doping and microgrid design.We conclude that isolated/small-bundle,heavily doped metallic or semiconducting SWCNTs with a large diameter,long length and high crystallinity are necessary to fabricate high-performance SWCNTTCFs.A simple,controllable way to construct macroscopic SWCNT networks with Y-type connections,welded junctions or microgrid design is important in achieving a low resistivity.Finally,some insights into the key challenges in the manufacture and use of SWCNT TCFs and their prospects are presented,hoping to shed light on promoting the practical application of SWCNT TCFs in future flexible and stretchable optoelectronics.
