In this study,a series of Co_3O_4/ mildly oxidized graphite oxide(mGO) nanocatalysts(Co_3O_4/ mGO-l,Co_3O_4/ mGO-2 and Co_3O_4/mGO-3) were synthesized through solvothermal method and used as a mediator for the heterog...In this study,a series of Co_3O_4/ mildly oxidized graphite oxide(mGO) nanocatalysts(Co_3O_4/ mGO-l,Co_3O_4/ mGO-2 and Co_3O_4/mGO-3) were synthesized through solvothermal method and used as a mediator for the heterogeneous peroxymonosulfate(PMS)activation.The performance of CO_3O_4 / mGO/PMS system was investigated using acid orange 7(AO7).Results showed that Co_3O_4/mGO-3 had the best degradation efficiency of AO7 and the removal rate was above 90%in about 6 min.The phenomenon indicated the catalytic activity of Co_3O_4/mGO composites was related to the oxidation degree of graphite oxide(GO).In addition,experiments showed the content of Co_3O_4 had an effect on the catalytic activity.The composites were characterized with X-ray powder diffraction(XRD),FTIR,Raman,X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM).According to the charactrization and synergistic catalytic mechanism,the generation of Co—OH complexes found to be the initial step to activate PMS in the heterogeneous system of Co_3O_4/mGO hybrid.展开更多
The modified graphite anode materials have some prominent advantages over other anode materials in the industrial applications.A novel simple and gentle method is proposed to synthesize the mild expanded graphite micr...The modified graphite anode materials have some prominent advantages over other anode materials in the industrial applications.A novel simple and gentle method is proposed to synthesize the mild expanded graphite microspheres(MEGMs) from flake graphite spheres through a combined modified pressurized oxidation combined with the microwave treatment.The microstructural results demonstrate that moderately expanded MEGMs with an expansion volume between 4 and 10 ml·g^(-1)exhibit a highly microporous structure with an enlarged interlayer spacing,a decreased microcrystalline size,as well as an increased number of functional groups on the surface,resulting in the increased storage sites and spaces for lithium ions and the enhanced diffusion rate of lithium ions.When used as the anode material for lithium-ion batteries,the MEGM-T75t30 obtained by oxidation treatment at 75℃ for 30 min followed by microwave irradiation for expansion displays a high reversible capacity of 446.7 mAh·g^(-1) at 100 mA·g^(-1) after 100 cycles and excellent rate performance(330 and 116 mAh·g^(-1) at 800 and 3200 mA·g^(-1),respectively).Therefore,the MEGMs prepared by this convenient and mild method show excellent electrochemical properties and good application potential.展开更多
研究了氧化微扩层处理对天然鳞片石墨晶体结构、表面形貌及其电化学性能的影响。结果表明,经氧化微扩层处理后,鳞片石墨的平均层间距d002略微增大,平均晶粒尺寸显著减小,鳞片石墨颗粒表面出现刻蚀和片层剥落现象。氧化微扩层处理1 h后,...研究了氧化微扩层处理对天然鳞片石墨晶体结构、表面形貌及其电化学性能的影响。结果表明,经氧化微扩层处理后,鳞片石墨的平均层间距d002略微增大,平均晶粒尺寸显著减小,鳞片石墨颗粒表面出现刻蚀和片层剥落现象。氧化微扩层处理1 h后,鳞片石墨的首次可逆容量从331.9 m A·h/g提高至364.7 m A·h/g,首次库伦效率从86.5%提高至88.8%。经过氧化微扩层处理,石墨的平均晶粒尺寸减小,锂离子在碳层表面及边缘嵌入量增加;在石墨表面引入的纳米级孔隙结构进一步增大了锂离子存储空间;同时,对表面细小颗粒的刻蚀清除,使石墨比表面积减小,是可逆容量和首次库伦效率提高的主要原因。展开更多
基金Innovation Program of Shanghai Municipal Education Commission,China(No.12ZZ069)Research Fund for the Doctoral Program of Higher Education,China(No.20130075110006)
文摘In this study,a series of Co_3O_4/ mildly oxidized graphite oxide(mGO) nanocatalysts(Co_3O_4/ mGO-l,Co_3O_4/ mGO-2 and Co_3O_4/mGO-3) were synthesized through solvothermal method and used as a mediator for the heterogeneous peroxymonosulfate(PMS)activation.The performance of CO_3O_4 / mGO/PMS system was investigated using acid orange 7(AO7).Results showed that Co_3O_4/mGO-3 had the best degradation efficiency of AO7 and the removal rate was above 90%in about 6 min.The phenomenon indicated the catalytic activity of Co_3O_4/mGO composites was related to the oxidation degree of graphite oxide(GO).In addition,experiments showed the content of Co_3O_4 had an effect on the catalytic activity.The composites were characterized with X-ray powder diffraction(XRD),FTIR,Raman,X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM).According to the charactrization and synergistic catalytic mechanism,the generation of Co—OH complexes found to be the initial step to activate PMS in the heterogeneous system of Co_3O_4/mGO hybrid.
基金financially supported by the National Natural Science Foundation of China(Nos.51702191,51802325 and U1510134)the Natural Science Foundation of Shanxi Province,China(No.201901D111037)+3 种基金Scientific Research Foundation for Young Scientists of Shanxi Province,China(No.201901D211585)the Science and Technology Innovation Planning Project in Universities and Colleges of Shanxi Province of China(No.2019L0012)the Unveiling Bidding Projects of Shanxi Province,China(No.20191101008)the Shanxi“1331 Project”Key Innovative Research Team。
文摘The modified graphite anode materials have some prominent advantages over other anode materials in the industrial applications.A novel simple and gentle method is proposed to synthesize the mild expanded graphite microspheres(MEGMs) from flake graphite spheres through a combined modified pressurized oxidation combined with the microwave treatment.The microstructural results demonstrate that moderately expanded MEGMs with an expansion volume between 4 and 10 ml·g^(-1)exhibit a highly microporous structure with an enlarged interlayer spacing,a decreased microcrystalline size,as well as an increased number of functional groups on the surface,resulting in the increased storage sites and spaces for lithium ions and the enhanced diffusion rate of lithium ions.When used as the anode material for lithium-ion batteries,the MEGM-T75t30 obtained by oxidation treatment at 75℃ for 30 min followed by microwave irradiation for expansion displays a high reversible capacity of 446.7 mAh·g^(-1) at 100 mA·g^(-1) after 100 cycles and excellent rate performance(330 and 116 mAh·g^(-1) at 800 and 3200 mA·g^(-1),respectively).Therefore,the MEGMs prepared by this convenient and mild method show excellent electrochemical properties and good application potential.
文摘研究了氧化微扩层处理对天然鳞片石墨晶体结构、表面形貌及其电化学性能的影响。结果表明,经氧化微扩层处理后,鳞片石墨的平均层间距d002略微增大,平均晶粒尺寸显著减小,鳞片石墨颗粒表面出现刻蚀和片层剥落现象。氧化微扩层处理1 h后,鳞片石墨的首次可逆容量从331.9 m A·h/g提高至364.7 m A·h/g,首次库伦效率从86.5%提高至88.8%。经过氧化微扩层处理,石墨的平均晶粒尺寸减小,锂离子在碳层表面及边缘嵌入量增加;在石墨表面引入的纳米级孔隙结构进一步增大了锂离子存储空间;同时,对表面细小颗粒的刻蚀清除,使石墨比表面积减小,是可逆容量和首次库伦效率提高的主要原因。