Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus en...Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus enhancing both ions and electrons transport.Here,sustainable bacterial cellulose(BC)is used both precursor and template for facile synthesis of free-standing N,S-codoped 3Dcarbon networks(a-NSC)by the pyrolysis and activation of polyrhodanine coated BC.The synthesized a-NSC shows highly conductive interconnected porous networks(24S·cm^(-1)),large surface area(1 420m^2·g^(-1))with hierarchical meso-microporosity,and high-level heteroatoms codoping(N:3.1%in atom,S:3.2%in atom).Benefitting from these,a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340F·g^(-1)(24μF·cm^(-2))at the current density of 0.5A·g^(-1)in 6MKOH electrolyte,high-rate capability(71%at 20A·g^(-1))and excellent cycle stability.Furthermore,the assembled symmetrical supercapacitor displays a much short time constant of 0.35sin 1MTEABF4/AN electrolyte,obtaining a maximum energy density of 32.1W·h·kg^(-1 )at power density of 637W·kg^(-1).The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications,which can be extended to other dimensional carbon nanostructures.展开更多
In present work, the metal-ceramic interpenetrating composites (IPCs) as AlSi11/ Si3N4 are fabricated by infiltrating technique. IPCs exhibit special characterization of brittle ceramic reinforced phase introduced by ...In present work, the metal-ceramic interpenetrating composites (IPCs) as AlSi11/ Si3N4 are fabricated by infiltrating technique. IPCs exhibit special characterization of brittle ceramic reinforced phase introduced by ductile metal matrix phase. During the sliding wear processes, IPCs exhibit four wear mechanism such as initial adhesive wear, mixed adhesive and abrasive wear, adhesive wear and final abrasive wear. Reinforcements inhibit plastic flow and restrict propagation of wear cracks. Increase in the volume fraction of reinforcement leads to improvement in the wear resistance. Under higher load and lower round speed conditions, the friction coefficients are lower than that of relative conditions.展开更多
It is of vital importance to construct highly interconnected,macroporous photocatalyst to improve its efficiency and applicability in solar energy conversion and environment remediation.Graphitic-like C_3N_4(g-C_3N_4)...It is of vital importance to construct highly interconnected,macroporous photocatalyst to improve its efficiency and applicability in solar energy conversion and environment remediation.Graphitic-like C_3N_4(g-C_3N_4),as an analogy to two-dimensional(2D)graphene,is highly identified as a visible-lightresponsive polymeric semiconductor.Moreover,the feasibility of g-C_3N_4 in making porous structures has been well established.However,the preparation of macroporous g-C_3N_4 with abundant porous networks and exposure surface,still constitutes a difficulty.To solve it,we report a first facile preparation of bimodal macroporous g-C_3N_4 hybrids with abundant in-plane holes,which is simply enabled by in-situ modification through thermally treating the mixture of thiourea and SnCl_4(pore modifier)after rotary evaporation.For one hand,the formed in-plane macropores endow the g-C_3N_4 system with plentiful active sites and short,cross-plane diffusion channels that can greatly speed up mass transport and transfer.For another,the heterojunctions founded between g-C_3N_4 and SnO_2 consolidate the electron transfer reaction to greatly reduce the recombination probability.As a consequence,the resulted macroporous gC_3N_4/SnO_2 nanohybrid had a high specific surface area(SSA)of 44.3 m^2/g that was quite comparable to most nano/mesoporous g-C_3N_4 reported.The interconnected porous network also rendered a highly intensified light absorption by strengthening the light penetration.Together with the improved mass transport and electron transfer,the macroporous g-C_3N_4/SnO_2 hybrid exhibited about 2.4-fold increment in the photoactivity compared with pure g-C_3N_4.Additionally,the recyclability of such hybrid could be guaranteed after eight successive uses.展开更多
基金supported by the National Basic Research Program of China(973 Program)(No.2014CB239701)the National Natural Science Foundation of China(Nos.51672128,51372116,21773118)+2 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20150739,BK20151468)the Prospective Joint Research Project of Cooperative Innovation Fund of Jiangsu Province(No.BY2015003-7)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Three-dimensional(3D)carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus enhancing both ions and electrons transport.Here,sustainable bacterial cellulose(BC)is used both precursor and template for facile synthesis of free-standing N,S-codoped 3Dcarbon networks(a-NSC)by the pyrolysis and activation of polyrhodanine coated BC.The synthesized a-NSC shows highly conductive interconnected porous networks(24S·cm^(-1)),large surface area(1 420m^2·g^(-1))with hierarchical meso-microporosity,and high-level heteroatoms codoping(N:3.1%in atom,S:3.2%in atom).Benefitting from these,a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340F·g^(-1)(24μF·cm^(-2))at the current density of 0.5A·g^(-1)in 6MKOH electrolyte,high-rate capability(71%at 20A·g^(-1))and excellent cycle stability.Furthermore,the assembled symmetrical supercapacitor displays a much short time constant of 0.35sin 1MTEABF4/AN electrolyte,obtaining a maximum energy density of 32.1W·h·kg^(-1 )at power density of 637W·kg^(-1).The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications,which can be extended to other dimensional carbon nanostructures.
文摘In present work, the metal-ceramic interpenetrating composites (IPCs) as AlSi11/ Si3N4 are fabricated by infiltrating technique. IPCs exhibit special characterization of brittle ceramic reinforced phase introduced by ductile metal matrix phase. During the sliding wear processes, IPCs exhibit four wear mechanism such as initial adhesive wear, mixed adhesive and abrasive wear, adhesive wear and final abrasive wear. Reinforcements inhibit plastic flow and restrict propagation of wear cracks. Increase in the volume fraction of reinforcement leads to improvement in the wear resistance. Under higher load and lower round speed conditions, the friction coefficients are lower than that of relative conditions.
基金supported by the National Key Research and Development Program of China (2016YFB0700300)the National Natural Science Foundation of China (51503014, 51501008)the State Key Laboratory for Advanced Metals and Materials (2016Z-03)
文摘It is of vital importance to construct highly interconnected,macroporous photocatalyst to improve its efficiency and applicability in solar energy conversion and environment remediation.Graphitic-like C_3N_4(g-C_3N_4),as an analogy to two-dimensional(2D)graphene,is highly identified as a visible-lightresponsive polymeric semiconductor.Moreover,the feasibility of g-C_3N_4 in making porous structures has been well established.However,the preparation of macroporous g-C_3N_4 with abundant porous networks and exposure surface,still constitutes a difficulty.To solve it,we report a first facile preparation of bimodal macroporous g-C_3N_4 hybrids with abundant in-plane holes,which is simply enabled by in-situ modification through thermally treating the mixture of thiourea and SnCl_4(pore modifier)after rotary evaporation.For one hand,the formed in-plane macropores endow the g-C_3N_4 system with plentiful active sites and short,cross-plane diffusion channels that can greatly speed up mass transport and transfer.For another,the heterojunctions founded between g-C_3N_4 and SnO_2 consolidate the electron transfer reaction to greatly reduce the recombination probability.As a consequence,the resulted macroporous gC_3N_4/SnO_2 nanohybrid had a high specific surface area(SSA)of 44.3 m^2/g that was quite comparable to most nano/mesoporous g-C_3N_4 reported.The interconnected porous network also rendered a highly intensified light absorption by strengthening the light penetration.Together with the improved mass transport and electron transfer,the macroporous g-C_3N_4/SnO_2 hybrid exhibited about 2.4-fold increment in the photoactivity compared with pure g-C_3N_4.Additionally,the recyclability of such hybrid could be guaranteed after eight successive uses.
