以改进的hummers法制备氧化石墨,以硝酸钴、硝酸镍、硫代乙酰胺分别为钴源、镍源和硫源,以乙二胺为氧化石墨烯的还原剂及Ni Co_2S_4的形貌控制剂,通过水热法合成Ni Co_2S_4/RGO复合材料,用作锂离子电池负极材料,在电流密度100 m A/g下,5...以改进的hummers法制备氧化石墨,以硝酸钴、硝酸镍、硫代乙酰胺分别为钴源、镍源和硫源,以乙二胺为氧化石墨烯的还原剂及Ni Co_2S_4的形貌控制剂,通过水热法合成Ni Co_2S_4/RGO复合材料,用作锂离子电池负极材料,在电流密度100 m A/g下,50次循环后容量为920 m Ah/g,库伦效率高达98.5%表现了出色的循环性能。展开更多
Zn0.4Cd0.6S/TiO2/Reduced graphene oxide(Zn0.4Cd0.6S/TiO2/RGO)nano-photocatalyst was synthe-sized by a facile solvothermal method.During the reaction,TiO2 and Zn0.8Cd0.2S nanoparticles were evenly dispersed across the ...Zn0.4Cd0.6S/TiO2/Reduced graphene oxide(Zn0.4Cd0.6S/TiO2/RGO)nano-photocatalyst was synthe-sized by a facile solvothermal method.During the reaction,TiO2 and Zn0.8Cd0.2S nanoparticles were evenly dispersed across the surface of RGO,which enhanced response to visible light.The photocatalytic activity of as-synthesized Zn0.4Cd0.6S/TiO2/RGO nanocomposite was studied by means of degrading methylene blue(MB)through the irradiation of visible light.Compared with other nanocomposites,the Zn0.4Cd0.6S/TiO2/RGO nanocomposite showed the highest photocatalytic degradation efficiency(96%)and high stability,which was 5.4 times of photodegradation efficiency of pure TiO2.展开更多
以湿法制备的硫溶胶和氧化石墨烯为前驱体,采用水热法还原不同酸碱体系的氧化石墨烯,制备石墨烯-硫复合材料。通过XRD和场发射扫描电子显微镜（FESEM）等对产物进行分析。石墨烯以薄膜状包覆在硫颗粒表面。恒流充放电、交流阻抗和循环...以湿法制备的硫溶胶和氧化石墨烯为前驱体,采用水热法还原不同酸碱体系的氧化石墨烯,制备石墨烯-硫复合材料。通过XRD和场发射扫描电子显微镜（FESEM）等对产物进行分析。石墨烯以薄膜状包覆在硫颗粒表面。恒流充放电、交流阻抗和循环伏安测试结果表明：180℃、酸性条件下水热12 h制备的复合材料电化学性能较好,以0.2 m A/cm2的电流密度在1.5-3.0 V充放电,首次放电比容量为803.72 m Ah/g,循环20次衰减至592.40 m Ah/g,容量保持率为73.71%。展开更多
The popularity of lithium–sulfur batteries has been increasing gradually due to their ultrahigh theoretical specific capacity and energy density. Nevertheless, they also have lots of drawbacks to be overcome, such as...The popularity of lithium–sulfur batteries has been increasing gradually due to their ultrahigh theoretical specific capacity and energy density. Nevertheless, they also have lots of drawbacks to be overcome, such as poor conductivity, severe volume expansion, and serious“shuttle effect”. In this work, reduced graphene oxide/molybdenum dioxide(rGO/MoO_(2)) composite is synthesized and applied to modify polypropylene separator. The modified polypropylene separator introduces synergistic tri-functions of physical adsorption, chemical interaction and catalytic effects, which can inhibit the“shuttle effect” and enhance the electrochemical performances of lithium-sulfur batteries. In the prepared r GO/MoO_(2) composite, the polar MoO_(2) chemically adsorbs the intermediate lithium polysulfide, while the rGO with good electrical conductivity not only acts as a physical barrier to prevent diffusion of polysulfide ions, but also improves the conversion efficiency of active material intercepted on the separator. As a consequence, the battery assembled with rGO/MoO_(2) modified polypropylene separator exhibits a reversible capacity of 757.5 mAh·g^(-1) after 200 cycles at0.2 C with a negligible capacity decay of 0.207% per cycle,which indicates a good long-period cycling stability. Furthermore, the rate performance and self-discharge suppression are also improved by introducing modified polypropylene separator. It shows that rGO/MoO_(2) composite is a promising material for separator modification in lithium-sulfur batteries.展开更多
Lithium-sulfur(Li-S)battery is labeled as a promising high-energy-density battery system,but some inherent drawbacks of sulfur cathode materials using relatively complicated techniques impair the practical application...Lithium-sulfur(Li-S)battery is labeled as a promising high-energy-density battery system,but some inherent drawbacks of sulfur cathode materials using relatively complicated techniques impair the practical applications.Herein,an integrated approach is proposed to fabricate the high-performance rGO/VS_(4)/S cathode composites through a simple one-step solvothermal method,where nano sulfur and VS_(4) particles are uniformly distributed on the conductive rGO matrix.rGO and sulfiphilic VS_(4)provide electron transfer skeleton and physical/chemical anchor for soluble lithium polysulfides(LiPS).Meanwhile,VS_(4) could also act as an electrochemical mediator to efficiently enhance the utilization and reversible conversion of LiPS.Correspondingly,the rGO/VS_(4)/S composites maintain a high reversible capacity of 969 mAh/g at 0.2 C after 100 cycles,with a capacity retention rate of 82.3%.The capacity fade rate could lower to 0.0374%per cycle at 1 C.Moreover,capacity still sustains 795 m Ah/g after 100 cycles in the relatively high-sulfurloading battery(6.5 mg/cm^(2)).Thus,the suggested method in configuring the sulfur-based composites is demonstrated a simple and efficient strategy to construct the high-performance Li-S batteries.展开更多
Graphitic carbon nitride(g-C3N4,CN)has attracted increasing interests in the field of photocatalysis due to its high visible-light-response.However,its photocatalytic activity is still lower for degradation of refract...Graphitic carbon nitride(g-C3N4,CN)has attracted increasing interests in the field of photocatalysis due to its high visible-light-response.However,its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(Ⅵ)and Rhodamine B(RhB)etc.Herein,we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide(rGO)porous nanosheet(S-CN/rGO PNs)via a supramolecular self-assembling followed by a solvothermal treatment.The as-prepared porous SCN/rGO PNs are stable with high specific surface area^188.5 m2 g-1 and exhibit a significantly enhanced photocatalytic activity of^17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(Ⅵ)under visible light irradiation,respectively.Typically,50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs.The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers.The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.展开更多
For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight&q...For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight" and given impetus to the universal's efforts to head for the same direction: stem the worst warming and strive for the renewable energy source. Hydrogen peroxide(H_2O_2) is undoubtedly a good choice,which holds the promise as a clean, efficient, safe and transferrable energy carrier. Octahedral coordination polymer, Cd_3(C_3N_3S_3)_2, was found to be a robust photocatalyst for H_2O_2 generation under visible light irradiation. To further improve the H_2O_2 generation efficiency, adhering the octahedron to reduced graphene(rGO) was applied as the strategy herein. The study shows that by adhering Cd_3(C_3N_3S_3)_2to rGO, the formation of H_2O_2 is 2.5-fold enhanced and its deformation is concurrently suppressed. This work not only demonstrates the effectiveness of adhering Cd_3(C_3N_3S_3)_2polymer to rGO for the improvement of the polymer's photocatalytic performance, but also proposes a general way for the fabrication of graphene/coordination compound hybrids for maximizing their synergy.展开更多
In regenerative medicine,a scaffold is needed to provide physical support for the growth of cells at the injury site.Carbon composites are also widely used in biomedicine.This research aimed to see if(MoWCu)S/rGO coul...In regenerative medicine,a scaffold is needed to provide physical support for the growth of cells at the injury site.Carbon composites are also widely used in biomedicine.This research aimed to see if(MoWCu)S/rGO could be used in peripheral and central neural regeneration as a carbon-based nanomaterial.This material was created using a one-step hydrothermal process.We used Scanning Electron Microscopy with Energy Dispersive X-ray analysis(SEM–EDX),X-ray diffraction,and Field-Emission Scanning Electron Microscopy(FE-SEM)to describe it.The researchers used animal models of spinal cord injury and sciatic nerve injury to assess its effect as a scaffold of anti-inflammatory and electrical conductivity.The Basso Beattie Bresnahan locomotor rating scale and von Frey Filament were used to assess neuronal function after(MoWCu)S/rGO transplantation.In addition,the expression of p75 NTR and neurotrophic factors(BDNF,NT3,and NGF)mRNA in the experimental rats nerve was compared to the normal ones using Real-Time RT-qPCR.In the experimental groups,the use of(MoWCu)S/rGO resulted in a significant increase in neurotrophic factor gene expression,while p75 NTR was inversely decreased.In conclusion,we found that the nerve regeneration activity of the(MoWCu)S/rGO scaffold in rat models significantly increased motor function recovery in the treated groups.Furthermore,the current study explained the response of this composite to inflammatory neurodegenerative diseases.(MoWCu)S incorporation in graphene is thought to have excellent properties and may be used in regenerative medicine.展开更多
文摘以改进的hummers法制备氧化石墨,以硝酸钴、硝酸镍、硫代乙酰胺分别为钴源、镍源和硫源,以乙二胺为氧化石墨烯的还原剂及Ni Co_2S_4的形貌控制剂,通过水热法合成Ni Co_2S_4/RGO复合材料,用作锂离子电池负极材料,在电流密度100 m A/g下,50次循环后容量为920 m Ah/g,库伦效率高达98.5%表现了出色的循环性能。
文摘Zn0.4Cd0.6S/TiO2/Reduced graphene oxide(Zn0.4Cd0.6S/TiO2/RGO)nano-photocatalyst was synthe-sized by a facile solvothermal method.During the reaction,TiO2 and Zn0.8Cd0.2S nanoparticles were evenly dispersed across the surface of RGO,which enhanced response to visible light.The photocatalytic activity of as-synthesized Zn0.4Cd0.6S/TiO2/RGO nanocomposite was studied by means of degrading methylene blue(MB)through the irradiation of visible light.Compared with other nanocomposites,the Zn0.4Cd0.6S/TiO2/RGO nanocomposite showed the highest photocatalytic degradation efficiency(96%)and high stability,which was 5.4 times of photodegradation efficiency of pure TiO2.
文摘以湿法制备的硫溶胶和氧化石墨烯为前驱体,采用水热法还原不同酸碱体系的氧化石墨烯,制备石墨烯-硫复合材料。通过XRD和场发射扫描电子显微镜（FESEM）等对产物进行分析。石墨烯以薄膜状包覆在硫颗粒表面。恒流充放电、交流阻抗和循环伏安测试结果表明：180℃、酸性条件下水热12 h制备的复合材料电化学性能较好,以0.2 m A/cm2的电流密度在1.5-3.0 V充放电,首次放电比容量为803.72 m Ah/g,循环20次衰减至592.40 m Ah/g,容量保持率为73.71%。
基金financially supported by the National Natural Science Foundation of China (Nos.21606065 and 21676067)Anhui Provincial Natural Science Foundation (Nos.1708085QE98 and 1908085QE178)+1 种基金the Fundamental Research Funds for the Central Universities (Nos.JZ2017YYPY0253,JZ2017HGTB0198,JZ2018HGBZ0138 and PA2020GDGP0054)the Opening Project of CAS Key Laboratory of Materials for Energy Conversion (No.KF2018003)。
文摘The popularity of lithium–sulfur batteries has been increasing gradually due to their ultrahigh theoretical specific capacity and energy density. Nevertheless, they also have lots of drawbacks to be overcome, such as poor conductivity, severe volume expansion, and serious“shuttle effect”. In this work, reduced graphene oxide/molybdenum dioxide(rGO/MoO_(2)) composite is synthesized and applied to modify polypropylene separator. The modified polypropylene separator introduces synergistic tri-functions of physical adsorption, chemical interaction and catalytic effects, which can inhibit the“shuttle effect” and enhance the electrochemical performances of lithium-sulfur batteries. In the prepared r GO/MoO_(2) composite, the polar MoO_(2) chemically adsorbs the intermediate lithium polysulfide, while the rGO with good electrical conductivity not only acts as a physical barrier to prevent diffusion of polysulfide ions, but also improves the conversion efficiency of active material intercepted on the separator. As a consequence, the battery assembled with rGO/MoO_(2) modified polypropylene separator exhibits a reversible capacity of 757.5 mAh·g^(-1) after 200 cycles at0.2 C with a negligible capacity decay of 0.207% per cycle,which indicates a good long-period cycling stability. Furthermore, the rate performance and self-discharge suppression are also improved by introducing modified polypropylene separator. It shows that rGO/MoO_(2) composite is a promising material for separator modification in lithium-sulfur batteries.
基金supported by the National Natural Science Foundation of China(No.21905289)the Independent Cultivation Program of Innovation Team of Ji’nan City(No.2019GXRC011)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2020QE062)China Postdoctoral Science Foundation(No.2021T140268)。
文摘Lithium-sulfur(Li-S)battery is labeled as a promising high-energy-density battery system,but some inherent drawbacks of sulfur cathode materials using relatively complicated techniques impair the practical applications.Herein,an integrated approach is proposed to fabricate the high-performance rGO/VS_(4)/S cathode composites through a simple one-step solvothermal method,where nano sulfur and VS_(4) particles are uniformly distributed on the conductive rGO matrix.rGO and sulfiphilic VS_(4)provide electron transfer skeleton and physical/chemical anchor for soluble lithium polysulfides(LiPS).Meanwhile,VS_(4) could also act as an electrochemical mediator to efficiently enhance the utilization and reversible conversion of LiPS.Correspondingly,the rGO/VS_(4)/S composites maintain a high reversible capacity of 969 mAh/g at 0.2 C after 100 cycles,with a capacity retention rate of 82.3%.The capacity fade rate could lower to 0.0374%per cycle at 1 C.Moreover,capacity still sustains 795 m Ah/g after 100 cycles in the relatively high-sulfurloading battery(6.5 mg/cm^(2)).Thus,the suggested method in configuring the sulfur-based composites is demonstrated a simple and efficient strategy to construct the high-performance Li-S batteries.
基金the Science and Technology Major Project of Shanxi Province(Grant Numbers MC2016-06)National Natural Science Foundation of China(21173041)the Opening Project of Jiangsu Key Laboratory of Advanced Metallic Materials,China.
文摘Graphitic carbon nitride(g-C3N4,CN)has attracted increasing interests in the field of photocatalysis due to its high visible-light-response.However,its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(Ⅵ)and Rhodamine B(RhB)etc.Herein,we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide(rGO)porous nanosheet(S-CN/rGO PNs)via a supramolecular self-assembling followed by a solvothermal treatment.The as-prepared porous SCN/rGO PNs are stable with high specific surface area^188.5 m2 g-1 and exhibit a significantly enhanced photocatalytic activity of^17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(Ⅵ)under visible light irradiation,respectively.Typically,50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs.The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers.The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.
基金financially supported by the National Natural Science Foundation of China(21003021 and 21373051)
文摘For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight" and given impetus to the universal's efforts to head for the same direction: stem the worst warming and strive for the renewable energy source. Hydrogen peroxide(H_2O_2) is undoubtedly a good choice,which holds the promise as a clean, efficient, safe and transferrable energy carrier. Octahedral coordination polymer, Cd_3(C_3N_3S_3)_2, was found to be a robust photocatalyst for H_2O_2 generation under visible light irradiation. To further improve the H_2O_2 generation efficiency, adhering the octahedron to reduced graphene(rGO) was applied as the strategy herein. The study shows that by adhering Cd_3(C_3N_3S_3)_2to rGO, the formation of H_2O_2 is 2.5-fold enhanced and its deformation is concurrently suppressed. This work not only demonstrates the effectiveness of adhering Cd_3(C_3N_3S_3)_2polymer to rGO for the improvement of the polymer's photocatalytic performance, but also proposes a general way for the fabrication of graphene/coordination compound hybrids for maximizing their synergy.
文摘In regenerative medicine,a scaffold is needed to provide physical support for the growth of cells at the injury site.Carbon composites are also widely used in biomedicine.This research aimed to see if(MoWCu)S/rGO could be used in peripheral and central neural regeneration as a carbon-based nanomaterial.This material was created using a one-step hydrothermal process.We used Scanning Electron Microscopy with Energy Dispersive X-ray analysis(SEM–EDX),X-ray diffraction,and Field-Emission Scanning Electron Microscopy(FE-SEM)to describe it.The researchers used animal models of spinal cord injury and sciatic nerve injury to assess its effect as a scaffold of anti-inflammatory and electrical conductivity.The Basso Beattie Bresnahan locomotor rating scale and von Frey Filament were used to assess neuronal function after(MoWCu)S/rGO transplantation.In addition,the expression of p75 NTR and neurotrophic factors(BDNF,NT3,and NGF)mRNA in the experimental rats nerve was compared to the normal ones using Real-Time RT-qPCR.In the experimental groups,the use of(MoWCu)S/rGO resulted in a significant increase in neurotrophic factor gene expression,while p75 NTR was inversely decreased.In conclusion,we found that the nerve regeneration activity of the(MoWCu)S/rGO scaffold in rat models significantly increased motor function recovery in the treated groups.Furthermore,the current study explained the response of this composite to inflammatory neurodegenerative diseases.(MoWCu)S incorporation in graphene is thought to have excellent properties and may be used in regenerative medicine.
