The biggest challenge is to develop a low cost and readily available catalyst to replace expensive commercial Pt/C for efficient electrochemical oxygen reduction reaction(ORR).In this research,closo-[B_(12)H_(12)]^(2−...The biggest challenge is to develop a low cost and readily available catalyst to replace expensive commercial Pt/C for efficient electrochemical oxygen reduction reaction(ORR).In this research,closo-[B_(12)H_(12)]^(2−)and 1,10-phenanthroline-iron complexes were introduced into the porous metal-organic framework by impregnation method,and further annealing treatment achieved the successful anchoring of single-atom-Fe in B-doped CN Matrix(FeN4CB).The ORR activity of FeN4CB is comparable to the widely used commercial 20 wt%Pt/C.Where the half-wave potential(E_(1/2))in alkaline medium up to 0.84 V,and even in the face of challenging ORR in acidic medium,the E_(1/2)of ORR driven by FeN4CB is still as high as 0.81 V.When FeN4CB was used as air cathode,the open circuit voltage of Zn-air battery reaches 1.435 V,and the power density and specific capacity are as high as 177 mW cm^(−2)and 800 mAh g_(Zn)^(−1)(theoretical value:820 mAh g_(Zn)^(−1)),respectively.The dazzling point of FeN4CB also appears in the high ORR stability,whether in alkaline or acidic media,E_(1/2)and limiting current density are still close to the initial value after 5000 times cycles.After continuously running the charge-discharge test for 220 h,the charge voltage and discharge voltage of the rechargeable zinc-air battery with FeN4CB as the air cathode maintained the initial state.Density functional theory calculations reveals that introducing B atom to Fe–N4–C can adjust the electronic structure to easily break O=O bond and significantly reduce the energy barrier of the rate-determining step resulting in an improved ORR activity.展开更多
Over the past few decades,the design and development of carbon materials have occurred at a rapid pace.In particular,these porous graphene-like carbon nitride materials have received considerable attention due to thei...Over the past few decades,the design and development of carbon materials have occurred at a rapid pace.In particular,these porous graphene-like carbon nitride materials have received considerable attention due to their superior structures and performances in the energy transformation field.In this review,nitrogenated holey two-dimensional graphene and polymeric carbon nitride will be discussed in depth.The structural properties,synthetic methods,and applications including electrocatalytic reactions,such as hydrogen evolution reaction,oxygen reduction reaction,oxygen evolution reaction,and nitrogen reduction reaction,will be presented in detail.Finally,we will present the outlooks on the current obstacles to the development of carbon nitride materials.This comprehensive understanding will help guide and motivate researchers to develop and modify carbon nitride materials with better properties in the future.展开更多
Flexible and free-standing electrospun nanofibres have been used as electrode materials in electrochemical energy storage systems due to their versatile properties,such as mechanical stability,superb electrical conduc...Flexible and free-standing electrospun nanofibres have been used as electrode materials in electrochemical energy storage systems due to their versatile properties,such as mechanical stability,superb electrical conductivity,and high functionality.In energy storage systems such as metal-ion,metal-air,and metal-sulphur batteries,electrospun nanofibres are vital for constructing flexible electrodes and substantially enhancing their electrochemical properties.The need for flexible batteries has increased with increasing demand for new products such as wearable and flexible devices,including smartwatches and flexible displays.Conventional batteries have several semirigid to rigid components that limit their expansion in the flexible device market.The creation of flexible and wearable batteries with greater mechanical flexibility,higher energy,and substantial power density is critical in meeting the demand for these new electronic items.The implementation of carbon and carbon-derived composites into flexible electrodes is required to realize this goal.It is essential to understand recent advances and the comprehensive foundation behind the synthesis and assembly of various flexible electrospun nanofibres.The design of nanofibres,including those comprising carbon,N-doped carbon,hierarchical,porous carbon,and metal/metal oxide carbon composites,will be explored.We will highlight the merits of electrospun carbon flexible electrodes by describing porosity,surface area,binder-free and free-standing electrode construction,cycling stability,and performance rate.Significant scientific progress has been achieved and logistical challenges have been met in promoting secondary battery usage;therefore,this review of flexible electrode materials will advance this easily used and sought-after technology.The challenges and prospects involved in the timely development of carbon nanofibre composite flexible electrodes and batteries will be addressed.展开更多
Boron/nitrogen-co-doped carbon(BCN)nanosheets decorated with Fe_(2)O_(3) nanocrystals(Fe_(2)O_(3)–BCN)were cast on a glassy carbon electrode(GCE)and applied as an electrochemical sensor to effectively detect paraquat...Boron/nitrogen-co-doped carbon(BCN)nanosheets decorated with Fe_(2)O_(3) nanocrystals(Fe_(2)O_(3)–BCN)were cast on a glassy carbon electrode(GCE)and applied as an electrochemical sensor to effectively detect paraquat(PQ),a toxic herbicide,in aqueous environments.A linear experiment performed using square wave voltammetry(SWV)under optimized experimental conditions produced a decent linear relationship and a low detection limit(LOD)of 2.74 nmol/L(S/N=3).Repeatability,reproducibility,stability,and interference experiments confirmed that the Fe_(2)O_(3)–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules.Notably,the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples.To the best of our knowledge,this is the first study on the preparation of Fe_(2)O_(3)–BCN nanosheets for PQ detection.The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.展开更多
The sluggish kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have always restricted the development of lithium oxygen batteries(LOBs).Herein,hollow carbon spheres loaded with Pd/Pd_(4)S het...The sluggish kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have always restricted the development of lithium oxygen batteries(LOBs).Herein,hollow carbon spheres loaded with Pd/Pd_(4)S heterostructure(Pd/Pd_(4)S@HCS)were successfully prepared via the in-situ deposition to improve the electrocatalytic activities for both ORR and OER in LOBs.With the welldispersed Pd/Pd_(4)S nanoparticles,the hierarchical composite with large specific surface area offers favorable transport channels for ions,electron and oxygen.Especially,the Pd/Pd_(4)S nanoparticles could exhibit excellent electrochemical performance for ORR and OER due to their intrinsic catalytic property and interfacial effect from the heterostructure.Therefore,the LOBs with Pd/Pd_(4)S@HCS as cathode catalyst show improved specific capacities,good rate ability and stable cycling performance.展开更多
The temperature distribution of typical n-type polycrystalline silicon thin film transistors under selfheating(SH)stress is studied by finite element analysis.From both steady-state and transient thermal simulation,th...The temperature distribution of typical n-type polycrystalline silicon thin film transistors under selfheating(SH)stress is studied by finite element analysis.From both steady-state and transient thermal simulation,the influence of device power density,substrate material,and channel width on device temperature distribution is analyzed.This study is helpful to understand the mechanism of SH degradation,and to effectively alleviate the SH effect in device operation.展开更多
基金financially supported by the NSFC-Yunnan Joint Foundation(U2002213)the Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University(2019FY003025)the‘Double-First Class’University Construction Project(C176220100042 and CZ21623201)。
文摘The biggest challenge is to develop a low cost and readily available catalyst to replace expensive commercial Pt/C for efficient electrochemical oxygen reduction reaction(ORR).In this research,closo-[B_(12)H_(12)]^(2−)and 1,10-phenanthroline-iron complexes were introduced into the porous metal-organic framework by impregnation method,and further annealing treatment achieved the successful anchoring of single-atom-Fe in B-doped CN Matrix(FeN4CB).The ORR activity of FeN4CB is comparable to the widely used commercial 20 wt%Pt/C.Where the half-wave potential(E_(1/2))in alkaline medium up to 0.84 V,and even in the face of challenging ORR in acidic medium,the E_(1/2)of ORR driven by FeN4CB is still as high as 0.81 V.When FeN4CB was used as air cathode,the open circuit voltage of Zn-air battery reaches 1.435 V,and the power density and specific capacity are as high as 177 mW cm^(−2)and 800 mAh g_(Zn)^(−1)(theoretical value:820 mAh g_(Zn)^(−1)),respectively.The dazzling point of FeN4CB also appears in the high ORR stability,whether in alkaline or acidic media,E_(1/2)and limiting current density are still close to the initial value after 5000 times cycles.After continuously running the charge-discharge test for 220 h,the charge voltage and discharge voltage of the rechargeable zinc-air battery with FeN4CB as the air cathode maintained the initial state.Density functional theory calculations reveals that introducing B atom to Fe–N4–C can adjust the electronic structure to easily break O=O bond and significantly reduce the energy barrier of the rate-determining step resulting in an improved ORR activity.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(22001228)the“Double-First Class”University Construction Project(C176220100022 and C176220100042)+2 种基金the Major Science and Technology Project of Precious Metal Materials Genetic Engineering in Yunnan Province(2019ZE001-1 and 202002AB080001)the International Joint Research Center for Advanced Energy Materials of Yunnan Province(202003AE140001)Guangzhi Hu is grateful to the Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University(2019FY003025).
文摘Over the past few decades,the design and development of carbon materials have occurred at a rapid pace.In particular,these porous graphene-like carbon nitride materials have received considerable attention due to their superior structures and performances in the energy transformation field.In this review,nitrogenated holey two-dimensional graphene and polymeric carbon nitride will be discussed in depth.The structural properties,synthetic methods,and applications including electrocatalytic reactions,such as hydrogen evolution reaction,oxygen reduction reaction,oxygen evolution reaction,and nitrogen reduction reaction,will be presented in detail.Finally,we will present the outlooks on the current obstacles to the development of carbon nitride materials.This comprehensive understanding will help guide and motivate researchers to develop and modify carbon nitride materials with better properties in the future.
基金supported by the National Natural Science Foundation of China(51871119,51901100,22075141)High-Level Entrepreneurial and Innovative Talents Program of Jiangsu Province,NSFC-Yunnan Joint Foundation(U2002213)+5 种基金Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University(2019FY003025)Jiangsu Provincial Funds for Natural Science Foundation(BK20170793,BK20180015)Six Talent Peak Project of Jiangsu Province(2018-XCL-033)China Postdoctoral Science Foundation(2018M640481)Jiangsu-Innovate UK Business Competition(BZ2017061)Double Tops Joint Fund of the Yunnan Science and Technology Bureau and Yunnan University(2019FY003025).
文摘Flexible and free-standing electrospun nanofibres have been used as electrode materials in electrochemical energy storage systems due to their versatile properties,such as mechanical stability,superb electrical conductivity,and high functionality.In energy storage systems such as metal-ion,metal-air,and metal-sulphur batteries,electrospun nanofibres are vital for constructing flexible electrodes and substantially enhancing their electrochemical properties.The need for flexible batteries has increased with increasing demand for new products such as wearable and flexible devices,including smartwatches and flexible displays.Conventional batteries have several semirigid to rigid components that limit their expansion in the flexible device market.The creation of flexible and wearable batteries with greater mechanical flexibility,higher energy,and substantial power density is critical in meeting the demand for these new electronic items.The implementation of carbon and carbon-derived composites into flexible electrodes is required to realize this goal.It is essential to understand recent advances and the comprehensive foundation behind the synthesis and assembly of various flexible electrospun nanofibres.The design of nanofibres,including those comprising carbon,N-doped carbon,hierarchical,porous carbon,and metal/metal oxide carbon composites,will be explored.We will highlight the merits of electrospun carbon flexible electrodes by describing porosity,surface area,binder-free and free-standing electrode construction,cycling stability,and performance rate.Significant scientific progress has been achieved and logistical challenges have been met in promoting secondary battery usage;therefore,this review of flexible electrode materials will advance this easily used and sought-after technology.The challenges and prospects involved in the timely development of carbon nanofibre composite flexible electrodes and batteries will be addressed.
基金funded by the National Key Research and Development Program(No.2019YFC1804400)the National Natural Science Foundation of China(Nos.21974124,22004109,22076174)+3 种基金Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2016)Guangdong Third Generation Semiconductor Engineering Technology Development Center(No.2020GCZX007)the Yunnan Provincial Science and Technology Bureau and the Double Top Joint Fund of Yunnan University(No.2019FY003025)the Double First Class University Plan(No.C176220100042)。
文摘Boron/nitrogen-co-doped carbon(BCN)nanosheets decorated with Fe_(2)O_(3) nanocrystals(Fe_(2)O_(3)–BCN)were cast on a glassy carbon electrode(GCE)and applied as an electrochemical sensor to effectively detect paraquat(PQ),a toxic herbicide,in aqueous environments.A linear experiment performed using square wave voltammetry(SWV)under optimized experimental conditions produced a decent linear relationship and a low detection limit(LOD)of 2.74 nmol/L(S/N=3).Repeatability,reproducibility,stability,and interference experiments confirmed that the Fe_(2)O_(3)–BCN/GCE system exhibited decent electrochemical sensing performance for PQ molecules.Notably,the designed sensor showed high selectivity and a decent linear relationship with PQ concentration in natural water samples.To the best of our knowledge,this is the first study on the preparation of Fe_(2)O_(3)–BCN nanosheets for PQ detection.The proposed sensor can be employed as an effective alternative tool for distinguishing and processing PQ.
基金supported by the Taishan Scholars Programme of Shandong Province(No.tsqn20161004)Project for Scientific Research Innovation Team of Young Scholar in Colleges and Universities of Shandong Province(No.2019KJC025)+1 种基金Young Scholars Program of Shandong University(No.2019WLJH21)China Postdoctoral Science Foundation(No.2020M672054)。
文摘The sluggish kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)have always restricted the development of lithium oxygen batteries(LOBs).Herein,hollow carbon spheres loaded with Pd/Pd_(4)S heterostructure(Pd/Pd_(4)S@HCS)were successfully prepared via the in-situ deposition to improve the electrocatalytic activities for both ORR and OER in LOBs.With the welldispersed Pd/Pd_(4)S nanoparticles,the hierarchical composite with large specific surface area offers favorable transport channels for ions,electron and oxygen.Especially,the Pd/Pd_(4)S nanoparticles could exhibit excellent electrochemical performance for ORR and OER due to their intrinsic catalytic property and interfacial effect from the heterostructure.Therefore,the LOBs with Pd/Pd_(4)S@HCS as cathode catalyst show improved specific capacities,good rate ability and stable cycling performance.
基金supported by the National Natural Science Foundation of China (Grant No.60406001).
文摘The temperature distribution of typical n-type polycrystalline silicon thin film transistors under selfheating(SH)stress is studied by finite element analysis.From both steady-state and transient thermal simulation,the influence of device power density,substrate material,and channel width on device temperature distribution is analyzed.This study is helpful to understand the mechanism of SH degradation,and to effectively alleviate the SH effect in device operation.
