In this paper,three-dimensional(3D)hollow Ti_(3)C_(2)T_(x)MXene tubes(HTCTs)with more–O terminal groups and fewer–F groups are successfully prepared via the template-oriented electrostatic self-assembly and the subs...In this paper,three-dimensional(3D)hollow Ti_(3)C_(2)T_(x)MXene tubes(HTCTs)with more–O terminal groups and fewer–F groups are successfully prepared via the template-oriented electrostatic self-assembly and the subsequent annealing treatment.The obtained 3D hollow structure with large specific surface area,unique porous structure,and enlarged interlayer spacing could prevent the re-stacking of twodimensional(2D)sheets and shorten the diffusion pathway of ions.Furthermore,density functional theory(DFT)calculations and electrochemical tests reveal that Ti_(3)C_(2)O_(2)MXene possesses higher adsorption ability and lower diffusion barrier for K^(+)and Li^(+)compared to Ti_(3)C_(2)MXene dominated by–F terminal groups.Benefiting from the synergistic effect of the structural design and surface modification,the asprepared 3D HTCTs exhibit excellent electrochemical performance as anodes for K^(+)and Li^(+)storage compared with 2D Ti_(3)C_(2)T_(x)sheets(TCSs).展开更多
In this paper,sulfur doped g-C_(3)N_(4)(S-g-C_(3)N_(4))was successfully prepared at 500℃ for 3 h via a modified molten salt method using dicyandiamide as the main raw material,trithiocyanuric acid as the sulfur sourc...In this paper,sulfur doped g-C_(3)N_(4)(S-g-C_(3)N_(4))was successfully prepared at 500℃ for 3 h via a modified molten salt method using dicyandiamide as the main raw material,trithiocyanuric acid as the sulfur source and LiBreKCl as the reaction medium.The as-prepared SeCN5.0% sample(the mass ratio of trithiocyanuric acid to dicyandiamide was 5.0%)composed of irregular flakes showed a band gap of 1.83 eV,which was narrower than that(2.55 eV)of pristine g-C_(3)N_(4).The SeCN5.0% sample also exhibited an outstanding absorption capacity of visible light.Moreover,the photodegradation rate toward methylene blue and tetracycline were respectively 10 and 20 times as high as that of bulk g-C_(3)N_(4) prepared by conventional heating methods,confirming its superior photocatalytic performance.These results can be attributed to that the replacement of lattice nitrogen with sulfur atom tuned the electronic structure of g-C_(3)N_(4),improved the absorption of visible light,optimized the separation of photogenerated electron-hole pairs,and consequently enhanced the photocatalytic activity of g-C_(3)N_(4).Moreover,the trapping experiments implied that hole(ht)and superoxide radical($O2)were the main active species in the process of photodegradation.展开更多
Lithium-sulfur batteries(LSBs),owing to their much higher energy density compared to the traditional lithium-ion battery,are deemed as one of the most promising candidates for the energy storage system.However,several...Lithium-sulfur batteries(LSBs),owing to their much higher energy density compared to the traditional lithium-ion battery,are deemed as one of the most promising candidates for the energy storage system.However,several issues including shuttle effect,lithium dendrites,and volumetric expansion seriously impede the commercial applications of LSBs.One-dimensional carbon materials(1DCMs)have been widely used as the matrix material for LSBs due to their high surface area,superior conductivity,good flexibility,excellent mechanical stability,and functional modifiability.In this review,the recent progress in 1D carbon-based composites as cathode including metal compounds/1DCMs,MOFs/1DCMs,MXenes/1DCMs,and polymers/1DCMs were discussed.Different strategies for polysulfide confinement and analysis of the functions of various components in the composites were summarized detailly.In the end,the current challenges of LSBs were systematically summarized,and the future outlooks were proposed,aiming at providing a comprehensive insight into the design of new host materials for nextgeneration LSBs.展开更多
基金supported by the National Natural Science Foundation of China(52104309,52072274)the Natural Science Foundation of Hubei Province(2021CFB011)the Program of Hubei Province,China(T201602 and 2017CFA004)。
文摘In this paper,three-dimensional(3D)hollow Ti_(3)C_(2)T_(x)MXene tubes(HTCTs)with more–O terminal groups and fewer–F groups are successfully prepared via the template-oriented electrostatic self-assembly and the subsequent annealing treatment.The obtained 3D hollow structure with large specific surface area,unique porous structure,and enlarged interlayer spacing could prevent the re-stacking of twodimensional(2D)sheets and shorten the diffusion pathway of ions.Furthermore,density functional theory(DFT)calculations and electrochemical tests reveal that Ti_(3)C_(2)O_(2)MXene possesses higher adsorption ability and lower diffusion barrier for K^(+)and Li^(+)compared to Ti_(3)C_(2)MXene dominated by–F terminal groups.Benefiting from the synergistic effect of the structural design and surface modification,the asprepared 3D HTCTs exhibit excellent electrochemical performance as anodes for K^(+)and Li^(+)storage compared with 2D Ti_(3)C_(2)T_(x)sheets(TCSs).
基金This workwas financially supported by National Natural Science Foundation of China(Grant No.51872210 and 52072274)Program for Innovative Teams of Outstanding Young and Middle-aged Researchers in the Higher Education Institutions of Hubei Province(T201602)Key Program of Natural Science Foundation of Hubei Province,China(Grant/Award Number:2017CFA004).
文摘In this paper,sulfur doped g-C_(3)N_(4)(S-g-C_(3)N_(4))was successfully prepared at 500℃ for 3 h via a modified molten salt method using dicyandiamide as the main raw material,trithiocyanuric acid as the sulfur source and LiBreKCl as the reaction medium.The as-prepared SeCN5.0% sample(the mass ratio of trithiocyanuric acid to dicyandiamide was 5.0%)composed of irregular flakes showed a band gap of 1.83 eV,which was narrower than that(2.55 eV)of pristine g-C_(3)N_(4).The SeCN5.0% sample also exhibited an outstanding absorption capacity of visible light.Moreover,the photodegradation rate toward methylene blue and tetracycline were respectively 10 and 20 times as high as that of bulk g-C_(3)N_(4) prepared by conventional heating methods,confirming its superior photocatalytic performance.These results can be attributed to that the replacement of lattice nitrogen with sulfur atom tuned the electronic structure of g-C_(3)N_(4),improved the absorption of visible light,optimized the separation of photogenerated electron-hole pairs,and consequently enhanced the photocatalytic activity of g-C_(3)N_(4).Moreover,the trapping experiments implied that hole(ht)and superoxide radical($O2)were the main active species in the process of photodegradation.
基金financially supported by the National Natural Science Foundation of China(Nos.51872210,52072274,and 52104309)the Key Program of Natural Science Foundation of Hubei Province,China(No.2017CFA004)+1 种基金the Natural Science Foundation of Hubei Province(No.2021CFB011)the Scientific Research Project of Education Department of Hubei Province(No.D20201103)。
文摘Lithium-sulfur batteries(LSBs),owing to their much higher energy density compared to the traditional lithium-ion battery,are deemed as one of the most promising candidates for the energy storage system.However,several issues including shuttle effect,lithium dendrites,and volumetric expansion seriously impede the commercial applications of LSBs.One-dimensional carbon materials(1DCMs)have been widely used as the matrix material for LSBs due to their high surface area,superior conductivity,good flexibility,excellent mechanical stability,and functional modifiability.In this review,the recent progress in 1D carbon-based composites as cathode including metal compounds/1DCMs,MOFs/1DCMs,MXenes/1DCMs,and polymers/1DCMs were discussed.Different strategies for polysulfide confinement and analysis of the functions of various components in the composites were summarized detailly.In the end,the current challenges of LSBs were systematically summarized,and the future outlooks were proposed,aiming at providing a comprehensive insight into the design of new host materials for nextgeneration LSBs.
