To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high ...To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.展开更多
Lithium sulfide(Li_(2)S)is a promising cathode for a practical lithium-sulfur battery as it can be coupled with various safe lithium-free anodes.However,the high activation potential(>3.5 V)together with the shuttl...Lithium sulfide(Li_(2)S)is a promising cathode for a practical lithium-sulfur battery as it can be coupled with various safe lithium-free anodes.However,the high activation potential(>3.5 V)together with the shuttling of lithium polysulfides(LiPSs)bottleneck its practical uses.We are trying to present a catalysis solution to solve both problems simultaneously,specially with twinborn heterostructure to shoot off the trouble in interfacial contact between two solids,catalyst and Li_(2)S.As a typical example,a Co9S8/Li_(2)S heterostructure is reported here as a novel self-catalytic cathode through a co-recrystallization followed by a one-step carbothermic conversion.Co9S8 as the catalyst effectively lowers the Li_(2)S activation potential(<2.4 V)due to fully integrated and contacted interfaces and consistently promotes the conversion of LiPSs to suppress the shuttling.The obtained freestanding cathode of Co9S8/Li_(2)S heterostructures encapsulated in three-dimensional graphene shows a high capacity,reaching 92.6%of Li_(2)S theoretical capacity,high rate performance(739 mAh g1 at 2 C),and a low capacity fading(0.039%per cycle at 1 C over 900 cycles).Even under a high Li_(2)S loading of 12 mg cm^(-2)and a low E/S ratio of 5μL mgLi_(2)S^(-1),86%of theoretical capacity can be utilized.展开更多
Compressible supercapacitors play an increasingly significant role in flexible sensors and wearable electronic devices.However,the integration of mechanical compressibility and excellent electrochemical performance in...Compressible supercapacitors play an increasingly significant role in flexible sensors and wearable electronic devices.However,the integration of mechanical compressibility and excellent electrochemical performance into a single device remains a challenge.Herein,we demonstrate a compressible and high-performance supercapacitor based on an N-doped carbon foam elastomer with hierarchical carbon nanotubes.Hierarchically structured Fe3C@N-doped carbon nanotubes/N-doped carbon foam and Ni@N-doped carbon nanotubes/N-doped carbon foam have been synthesized via a simple and universal self-catalytic strategy.The hierarchical structural features of self-catalytic N-doped carbon nanotubes serve as a cushion when the composite is subjected to an external force,exhibiting excellent mechanical properties with a maximum compressive strain of 80%and fatigue resistance of 1000 cycles.Moreover,the different electroactive potentials of the transition-metal species in the composites provide the assembly with a maximum operating voltage of 1.4 V,which shows a maximum energy density of∼10.74 Wh kg^(−1)(0.084 mWh cm^(−3))at the power density of∼179.2 W kg^(−1)(1.4 mWh cm^(−3)),and retains 88.4%of the original capacitance after 20,000 charge–discharge cycles,even at a strain of 80%.This work paves the way for controllable fabrication of compressible electrodes and supercapacitors.展开更多
A number of industrial and biomedical fields,such as hydraulic fracturing balls for gas and petroleum exploitation and implant materials,require Mg alloys with rapid dissolution.An iron-bearing phosphate chemical conv...A number of industrial and biomedical fields,such as hydraulic fracturing balls for gas and petroleum exploitation and implant materials,require Mg alloys with rapid dissolution.An iron-bearing phosphate chemical conversion(PCC)coating with self-catalytic degradation function was fabricated on the Mg alloy AZ31.Surface morphologies,chemical compositions and degradation behaviors of the PCC coating were investigated through FE-SEM,XPS,XRD,FTIR,electrochemical and hydrogen evolution tests.Results indicated that the PCC coating was characterized by iron,its phosphates and hydroxides,amorphous Mg(OH)2 and Mg3-n(HnPO4)2.The self-catalytic degradation effects were predominately concerned with the Fe concentration,chemical composition and microstructure of the PCC coating,which were ascribed to the galvanic corrosion between Fe in the PCC coating and the Mg substrate.The coating with higher Fe content and porous microstructure exhibited a higher degradation rate than that of the AZ31 substrate,while the coating with a trace of Fe and compact surface disclosed a slightly enhanced corrosion resistance for the AZ31 substrate.展开更多
基金supported by the National Key R&D Program of China(2019YFA0110600 and 2019YFA0110601)National Natural Science Foundation of China(Nos.51603134,51903178,51803134,and 51703141)+1 种基金Sichuan Province’s Science and Technology Planning Project(No.2016GZ0350)the Postgraduate Course Construction Project of Sichuan University(No.2017KCSJ036)and for their financial support.
文摘To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.
基金National Key Research and Development Program of China,Grant/Award Numbers:2018YFE0124500,2021YFF0500600National Natural Science Foundation of China,Grant/Award Numbers:52022041,51932005+1 种基金The Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program,Grant/Award Number:2017BT01N111Shenzhen Basic Research Project,Grant/Award Number:JCYJ20180508152037520。
文摘Lithium sulfide(Li_(2)S)is a promising cathode for a practical lithium-sulfur battery as it can be coupled with various safe lithium-free anodes.However,the high activation potential(>3.5 V)together with the shuttling of lithium polysulfides(LiPSs)bottleneck its practical uses.We are trying to present a catalysis solution to solve both problems simultaneously,specially with twinborn heterostructure to shoot off the trouble in interfacial contact between two solids,catalyst and Li_(2)S.As a typical example,a Co9S8/Li_(2)S heterostructure is reported here as a novel self-catalytic cathode through a co-recrystallization followed by a one-step carbothermic conversion.Co9S8 as the catalyst effectively lowers the Li_(2)S activation potential(<2.4 V)due to fully integrated and contacted interfaces and consistently promotes the conversion of LiPSs to suppress the shuttling.The obtained freestanding cathode of Co9S8/Li_(2)S heterostructures encapsulated in three-dimensional graphene shows a high capacity,reaching 92.6%of Li_(2)S theoretical capacity,high rate performance(739 mAh g1 at 2 C),and a low capacity fading(0.039%per cycle at 1 C over 900 cycles).Even under a high Li_(2)S loading of 12 mg cm^(-2)and a low E/S ratio of 5μL mgLi_(2)S^(-1),86%of theoretical capacity can be utilized.
基金National Natural Science Foundation of China(grant nos.21805051 and 21875048)Outstanding Youth Project of Guangdong Natural Science Foundation(grant no.2020B1515020028)+3 种基金University Innovation Team Scientific Research Project of Guangzhou Education Bureau(grant no.202235246)Science and Technology Research Project of Guangzhou(grant nos.202102020376 and 202201020214)Guangdong University Student Science and Technology Innovation Climbing Program(grant no.pdjh2022b0415)2022 Innovation Training Program for College Students(grant no.s202211078133).
文摘Compressible supercapacitors play an increasingly significant role in flexible sensors and wearable electronic devices.However,the integration of mechanical compressibility and excellent electrochemical performance into a single device remains a challenge.Herein,we demonstrate a compressible and high-performance supercapacitor based on an N-doped carbon foam elastomer with hierarchical carbon nanotubes.Hierarchically structured Fe3C@N-doped carbon nanotubes/N-doped carbon foam and Ni@N-doped carbon nanotubes/N-doped carbon foam have been synthesized via a simple and universal self-catalytic strategy.The hierarchical structural features of self-catalytic N-doped carbon nanotubes serve as a cushion when the composite is subjected to an external force,exhibiting excellent mechanical properties with a maximum compressive strain of 80%and fatigue resistance of 1000 cycles.Moreover,the different electroactive potentials of the transition-metal species in the composites provide the assembly with a maximum operating voltage of 1.4 V,which shows a maximum energy density of∼10.74 Wh kg^(−1)(0.084 mWh cm^(−3))at the power density of∼179.2 W kg^(−1)(1.4 mWh cm^(−3)),and retains 88.4%of the original capacitance after 20,000 charge–discharge cycles,even at a strain of 80%.This work paves the way for controllable fabrication of compressible electrodes and supercapacitors.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51571134)the Scientific Research Foundation of Shandong University of Science and Technology Research Fund(2014TDJH104).
文摘A number of industrial and biomedical fields,such as hydraulic fracturing balls for gas and petroleum exploitation and implant materials,require Mg alloys with rapid dissolution.An iron-bearing phosphate chemical conversion(PCC)coating with self-catalytic degradation function was fabricated on the Mg alloy AZ31.Surface morphologies,chemical compositions and degradation behaviors of the PCC coating were investigated through FE-SEM,XPS,XRD,FTIR,electrochemical and hydrogen evolution tests.Results indicated that the PCC coating was characterized by iron,its phosphates and hydroxides,amorphous Mg(OH)2 and Mg3-n(HnPO4)2.The self-catalytic degradation effects were predominately concerned with the Fe concentration,chemical composition and microstructure of the PCC coating,which were ascribed to the galvanic corrosion between Fe in the PCC coating and the Mg substrate.The coating with higher Fe content and porous microstructure exhibited a higher degradation rate than that of the AZ31 substrate,while the coating with a trace of Fe and compact surface disclosed a slightly enhanced corrosion resistance for the AZ31 substrate.
