The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H_(2).Unfortunately,the variant energy-level matching between two different semicondu...The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H_(2).Unfortunately,the variant energy-level matching between two different semiconductor confers limited the photocatalytic performance.Herein,a newfangled graphitic-carbon nitride(g-C_(3)N_(4))based isotype step-scheme heterojunction,which consists of sulfur-doped and defective active sites in one microstructural unit,is successfully developed by in-situ polymerizing N,N-dimethylformamide(DMF)and urea,accompanied by sulfur(S)powder.Therein,the polymerization between the amino groups of DMF and the amide group of urea endows the formation of rich defects.The propulsive integration of S-dopants contributes to the excellent fluffiness and dispersibility of lamellar g-C_(3)N_(4).Moreover,the developed heterojunction exhibits a significantly enlarged surface area,thus leading to the more exposed catalytically active sites.Most importantly,the simultaneous introduction of S-doping and defects in the units of g-C_(3)N_(4) also results in a significant improvement in the separation,transfer and recombination efficiency of photo-excited electron-hole pairs.Therefore,the resulting isotype step-scheme heterojunction possesses a superior photocatalytic H_(2) evolution activity in comparison with pristine g-C_(3)N_(4).The newly afforded metal-free isotype step-scheme heterojunction in this work will supply a new insight into coupling strategies of heteroatoms doping and defect engineering for various photocatalytic systems.展开更多
Carbonaceous materials are promising anode candidates for potassium-ion batteries, but currently the unsatisfactory cycling and rate performances due to the sluggish diffusion kinetic and serious structure damage duri...Carbonaceous materials are promising anode candidates for potassium-ion batteries, but currently the unsatisfactory cycling and rate performances due to the sluggish diffusion kinetic and serious structure damage during K+ insertion/extraction limit their practical application. Herein, a series of sulfur-doped porous carbons(SPCs) were prepared via a template-assisted freeze-drying followed by the carbonization and sulfuration processes at different temperatures. Among the three as-synthesized samples, SPC-600 exhibits the highest specific capacity(407 mAh·g^(-1) at 0.10 A·g^(-1)), the best rate(242 mAh·g^(-1) at 2.00 A·g^(-1)) and cycling performance(286 m Ah·g^(-1) after 800 cycles at 0.50 A·g^(-1)). All the SPCs display higher capacities than the undoped carbon materials. The excellent electrochemical performance of SPC can be ascribed to the abundant three-dimensional porous structure together with S-doping in the disordered carbon, which is favor of providing adequate reaction active sites as well as fast ion/electron transport paths. The density functional theory(DFT) calculations further demonstrate that the sulfurdoping can promote K-ion adsorption and storage. Meanwhile, the kinetic analyses reveal that surface-induced capacitive mechanism dominates the K-ion storage process in SPCs, which contributes to ultrafast charge storage. This work provides an effective strategy for fabricating highperformance potassium-ion storage electrode materials.展开更多
Hard carbon is promising anode for potassium-ion batteries(PIBs),however,the poor rate capability hinders its development as potential anode.To address this question,we design a sulfur-doped porous hard carbon(S-HC)fo...Hard carbon is promising anode for potassium-ion batteries(PIBs),however,the poor rate capability hinders its development as potential anode.To address this question,we design a sulfur-doped porous hard carbon(S-HC)for PIBs through the combination of structural design and composition adjustment.The as-designed S-HC exhibits a long cycling life with^191 mAh/g after 300 cycles at 1 A/g,and an excellent rate capability with^100 mAh/g at 5 A/g,which was attributed to its structural characteristics and compositions.The S-HC demonstrates to be promising anode in the future.展开更多
Heteroatom-doped porous carbon materials are very attractive for lithium ion batteries(LIBs) owing to their high specific surface areas, open pore structures, and abundant active sites. However, heteroatomdoped porous...Heteroatom-doped porous carbon materials are very attractive for lithium ion batteries(LIBs) owing to their high specific surface areas, open pore structures, and abundant active sites. However, heteroatomdoped porous carbon with very high surface area and large pore volume are highly desirable but still remain a big challenge. Herein, we reported a sulfur-doped mesoporous carbon(CMK-5-S) with nanotubes array structure, ultrahigh specific surface area(1390 m^(2)/g), large pore volume(1.8 cm^(3)/g), bimodal pore size distribution(2.9 and 4.6 nm), and high sulfur content(2.5 at%). The CMK-5-S used as an anode material for LIBs displays high specific capacity, excellent rate capability and highly cycling stability. The initial reversible specific capacity at 0.1 A/g is as high as 1580 mAh/g and simultaneously up to 701 mAh/g at 1A/g even after 500 cycles. Further analysis reveals that the excellent electrochemical storage performances is attributed to its unique structures as well as the expanded lattice by sulfur-doping.展开更多
Metal-free carbon electrocatalyts for the oxygen reduction reaction (ORR) are attractive for their high activity and economic advantages. However, the origin of the activity has never been clearly elucidated in a syst...Metal-free carbon electrocatalyts for the oxygen reduction reaction (ORR) are attractive for their high activity and economic advantages. However, the origin of the activity has never been clearly elucidated in a systematic manner. Halogen group elements are good candidates for elucidating the effect, although it has been a difficult task due to safety issues. In this report, we demonstrate the synthesis of Cl-, Br- and I-doped reduced graphene oxide through two solution phase syntheses. We have evaluated the effectiveness of doping and performed electrochemical measurements of the ORR activity on these halogenated graphene materials. Our results suggest that the high electroneg-ativity of the dopant is not the key factor for high ORR activity; both Br- and I-doped graphene promoted ORR more efficiently than Cl-doped graphene. Furthermore, an unexpected sulfur-doping in acidic conditions suggests that a high level of sulfide can degrade the ORR activity of the graphene material.展开更多
A sol-gel method was used to prepare TiO_2 and sulfur-TiO_2(S-TiO_2) nanocomposites, which were characterized by N_2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescene, ultrav...A sol-gel method was used to prepare TiO_2 and sulfur-TiO_2(S-TiO_2) nanocomposites, which were characterized by N_2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescene, ultraviolet visible and transmission electron microscopy measurements. The photocatalytic performance of TiO_2 and S-TiO_2 nanocomposites, with respect to the photocatalytic oxidation of cyanide under visible light irradiation, was determined. The results reveal that S is well dispersed on the surface of TiO_2 nanoparticles. Additionally, the surface area of the S-TiO_2 nanocomposites was observed to be smaller than that of the TiO_2 nanoparticles because of blocked pores caused by doping with S. The S-TiO_2 nanocomposite(0.3 wt% S) exhibited the lowest band gap and the highest photocatalytic activity in the oxidation of cyanide. The photocatalytic performance of S-TiO_2(0.3 wt% S) nanocomposites was stable, even after the fifth reuse of the nanoparticles for the oxidation of cyanide.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.62004143)the Central Government Guided Local Science and Technology Development Special Fund Project(No.2020ZYYD033)+4 种基金the Natural Science Foundation of Hubei Province(No.2021CFB133)the Opening Fund of Key Laboratory of Rare Mineral Ministry of Natural Resources(No.KLRM-KF 202005)the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage(HUST),Ministry of Education(No.2021JYBKF05)the Opening Fund of Key Laboratory for Green Chemical Process of Ministry of Education of Wuhan Institute of Technology(No.GCP202101)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education(No.LCX2021003)。
文摘The rational construction of a high-efficiency stepscheme heterojunctions is an effective strategy to accelerate the photocatalytic H_(2).Unfortunately,the variant energy-level matching between two different semiconductor confers limited the photocatalytic performance.Herein,a newfangled graphitic-carbon nitride(g-C_(3)N_(4))based isotype step-scheme heterojunction,which consists of sulfur-doped and defective active sites in one microstructural unit,is successfully developed by in-situ polymerizing N,N-dimethylformamide(DMF)and urea,accompanied by sulfur(S)powder.Therein,the polymerization between the amino groups of DMF and the amide group of urea endows the formation of rich defects.The propulsive integration of S-dopants contributes to the excellent fluffiness and dispersibility of lamellar g-C_(3)N_(4).Moreover,the developed heterojunction exhibits a significantly enlarged surface area,thus leading to the more exposed catalytically active sites.Most importantly,the simultaneous introduction of S-doping and defects in the units of g-C_(3)N_(4) also results in a significant improvement in the separation,transfer and recombination efficiency of photo-excited electron-hole pairs.Therefore,the resulting isotype step-scheme heterojunction possesses a superior photocatalytic H_(2) evolution activity in comparison with pristine g-C_(3)N_(4).The newly afforded metal-free isotype step-scheme heterojunction in this work will supply a new insight into coupling strategies of heteroatoms doping and defect engineering for various photocatalytic systems.
基金financially supported by the National Natural Science Foundation of China(Nos.51871046,51902046,52071073,51874079,51571054,51771046 and 51674068)the Natural Science Foundation of Liaoning Province(No.201602257)+5 种基金the Natural Science Foundation of Hebei Province(Nos.E2019501097,E2018501091 and E2020501004)the Science and Technology Project of Hebei Province(No.15271302D)the Training Foundation for Scientific Research of Talents Project Hebei Province(No.A2016005004)the Young Talents Program in University of Hebei Province(No.BJ2018014)Hebei Province Higher Education Science and Technology Research Project(No.QN2017103)the Fundamental Research Funds for the Central Universities(Nos.N182304017,N182304015,N172302001 and N172304044)。
文摘Carbonaceous materials are promising anode candidates for potassium-ion batteries, but currently the unsatisfactory cycling and rate performances due to the sluggish diffusion kinetic and serious structure damage during K+ insertion/extraction limit their practical application. Herein, a series of sulfur-doped porous carbons(SPCs) were prepared via a template-assisted freeze-drying followed by the carbonization and sulfuration processes at different temperatures. Among the three as-synthesized samples, SPC-600 exhibits the highest specific capacity(407 mAh·g^(-1) at 0.10 A·g^(-1)), the best rate(242 mAh·g^(-1) at 2.00 A·g^(-1)) and cycling performance(286 m Ah·g^(-1) after 800 cycles at 0.50 A·g^(-1)). All the SPCs display higher capacities than the undoped carbon materials. The excellent electrochemical performance of SPC can be ascribed to the abundant three-dimensional porous structure together with S-doping in the disordered carbon, which is favor of providing adequate reaction active sites as well as fast ion/electron transport paths. The density functional theory(DFT) calculations further demonstrate that the sulfurdoping can promote K-ion adsorption and storage. Meanwhile, the kinetic analyses reveal that surface-induced capacitive mechanism dominates the K-ion storage process in SPCs, which contributes to ultrafast charge storage. This work provides an effective strategy for fabricating highperformance potassium-ion storage electrode materials.
基金supported by the National Natural Science Foundation of China (Nos.21905086,51971090)the Key Research and Development Program of Hunan Province of China (No. 2018GK2031)the Natural Science Foundation of Hunan Province (No.2017JJ1008)
文摘Hard carbon is promising anode for potassium-ion batteries(PIBs),however,the poor rate capability hinders its development as potential anode.To address this question,we design a sulfur-doped porous hard carbon(S-HC)for PIBs through the combination of structural design and composition adjustment.The as-designed S-HC exhibits a long cycling life with^191 mAh/g after 300 cycles at 1 A/g,and an excellent rate capability with^100 mAh/g at 5 A/g,which was attributed to its structural characteristics and compositions.The S-HC demonstrates to be promising anode in the future.
基金funding from the National Key R&D Program of China (No. 2018YFE0201703)the National Natural Science Foundation of China (Nos. 22272120, U2202251)the “1000-Youth Talents Plan”。
文摘Heteroatom-doped porous carbon materials are very attractive for lithium ion batteries(LIBs) owing to their high specific surface areas, open pore structures, and abundant active sites. However, heteroatomdoped porous carbon with very high surface area and large pore volume are highly desirable but still remain a big challenge. Herein, we reported a sulfur-doped mesoporous carbon(CMK-5-S) with nanotubes array structure, ultrahigh specific surface area(1390 m^(2)/g), large pore volume(1.8 cm^(3)/g), bimodal pore size distribution(2.9 and 4.6 nm), and high sulfur content(2.5 at%). The CMK-5-S used as an anode material for LIBs displays high specific capacity, excellent rate capability and highly cycling stability. The initial reversible specific capacity at 0.1 A/g is as high as 1580 mAh/g and simultaneously up to 701 mAh/g at 1A/g even after 500 cycles. Further analysis reveals that the excellent electrochemical storage performances is attributed to its unique structures as well as the expanded lattice by sulfur-doping.
基金financial support from The University of Queensland and the Australian Research Council Discovery Project (DP110100550)
文摘Metal-free carbon electrocatalyts for the oxygen reduction reaction (ORR) are attractive for their high activity and economic advantages. However, the origin of the activity has never been clearly elucidated in a systematic manner. Halogen group elements are good candidates for elucidating the effect, although it has been a difficult task due to safety issues. In this report, we demonstrate the synthesis of Cl-, Br- and I-doped reduced graphene oxide through two solution phase syntheses. We have evaluated the effectiveness of doping and performed electrochemical measurements of the ORR activity on these halogenated graphene materials. Our results suggest that the high electroneg-ativity of the dopant is not the key factor for high ORR activity; both Br- and I-doped graphene promoted ORR more efficiently than Cl-doped graphene. Furthermore, an unexpected sulfur-doping in acidic conditions suggests that a high level of sulfide can degrade the ORR activity of the graphene material.
文摘A sol-gel method was used to prepare TiO_2 and sulfur-TiO_2(S-TiO_2) nanocomposites, which were characterized by N_2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescene, ultraviolet visible and transmission electron microscopy measurements. The photocatalytic performance of TiO_2 and S-TiO_2 nanocomposites, with respect to the photocatalytic oxidation of cyanide under visible light irradiation, was determined. The results reveal that S is well dispersed on the surface of TiO_2 nanoparticles. Additionally, the surface area of the S-TiO_2 nanocomposites was observed to be smaller than that of the TiO_2 nanoparticles because of blocked pores caused by doping with S. The S-TiO_2 nanocomposite(0.3 wt% S) exhibited the lowest band gap and the highest photocatalytic activity in the oxidation of cyanide. The photocatalytic performance of S-TiO_2(0.3 wt% S) nanocomposites was stable, even after the fifth reuse of the nanoparticles for the oxidation of cyanide.
