Pitch and TiB2/C green composite cathode material were respectively analyzed with simultaneous DSC-TGA, and effects of three baking processes of TiB2/C composite cathode material, i.e. K25, K5 and M5, on properties of...Pitch and TiB2/C green composite cathode material were respectively analyzed with simultaneous DSC-TGA, and effects of three baking processes of TiB2/C composite cathode material, i.e. K25, K5 and M5, on properties of TiB2/C composite cathode material were investigated. The results show that thermogravimetrie behavior of pitch and TiB2/C green composite cathode is similar, and appears the largest mass loss rate in the temperature range from 200 to 600 ℃. The bulk density variation of sample K5 before and after baking is the largest （11.9%）, that of sample K25 is the second, and that of sample M5 is the smallest （6.7%）. The crushing strength of sample M5 is the biggest （51.2 MPa）, that of sample K2.5 is the next, and that of sample K5 is the smallest （32.8 MPa）. But, the orders of the electrical resistivity and electrolysis expansion of samples are just opposite with the order of crushing strength. The heating rate has a great impact on the microstructure of sample. The faster the heating rate is, the bigger the pore size and porosity of sample are. Compared with the heating rate between 200 and 600℃ of samples K25 and K5, that of sample M5 is slower and suitable for baking process of TiB2/C composite cathode material.展开更多
Hierarchical mesoporous MoO2/Mo2C/C microspheres,which are composed of primary nanoparticles with a size of about 30 nm,have been designed and synthesized through polymer regulation and subsequent carbonization proces...Hierarchical mesoporous MoO2/Mo2C/C microspheres,which are composed of primary nanoparticles with a size of about 30 nm,have been designed and synthesized through polymer regulation and subsequent carbonization processes.The as-synthesized microspheres were characterized by XRD,Raman,SEM,TEM,XPS measurements and so on.It was found that polyethylene glycol acted as a structure-directing agent,mild reducing agent and carbon source in the formation of these hierarchical mesoporous Mo O2/Mo2C/C microspheres.Moreover,the electrochemical property of the microspheres was also investigated in this work.Evaluated as an anode material for lithium ion batteries,the hierarchical mesoporous Mo O2/Mo2C/C electrode delivered the discharge specific capacities of 665 and 588 m Ah/g after 100 cycles at current densities of 100 and 200 m A/g,respectively.The satisfactory cycling performance and controllable process facilitate the practical applications of the hierarchical mesoporous Mo O2/Mo2C/C as a potential anode material in high-energy density lithium-ion batteries.展开更多
采用包覆的方法制备出MO/C型复合电极材料,通过X射线衍射(XRD)对复合材料的结构组成进行表征分析,另外通过循环伏安法、计时电位法和交流阻抗技术对复合电极材料在6 M KOH溶液中的电化学电容性能进行考查。结果表明:包覆了过渡金属锰氧...采用包覆的方法制备出MO/C型复合电极材料,通过X射线衍射(XRD)对复合材料的结构组成进行表征分析,另外通过循环伏安法、计时电位法和交流阻抗技术对复合电极材料在6 M KOH溶液中的电化学电容性能进行考查。结果表明:包覆了过渡金属锰氧化物的复合电极材料在0.5 A/g的电流密度下比电容最高可达218.3 F/g。此外,MO/C型复合电极材料表现出较好的功率性能,当电流密度增加到5 A/g,其比电容值达到168.0 F/g,其电容保持率为77.0%,表明这是一种很有前景的电极材料。展开更多
通过溶剂热法制备了球状C-TiO_(2)催化剂以及BiOCl/C-TiO_(2)复合光催化材料。与纯TiO_(2)相比,球状C-TiO_(2)和BiOCl/C-TiO_(2)的禁带宽度显著降低。以亚甲基蓝为降解目标,当染料质量浓度为25 mg/L、pH为7时,0.1 g BiOCl/CTiO_(2)对其...通过溶剂热法制备了球状C-TiO_(2)催化剂以及BiOCl/C-TiO_(2)复合光催化材料。与纯TiO_(2)相比,球状C-TiO_(2)和BiOCl/C-TiO_(2)的禁带宽度显著降低。以亚甲基蓝为降解目标,当染料质量浓度为25 mg/L、pH为7时,0.1 g BiOCl/CTiO_(2)对其的降解率在1 h可达到81.44%,催化效率达64.15%,其动力学过程符合一级动力学模型。展开更多
B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel.In order to improve the high-temperature mechanical properties of B_(4)C/Al composites,i...B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel.In order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder surface.In this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al composites.It was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high temperature.As the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased significantly.The finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.展开更多
In view of recent environmental concerns,electrochemical water splitting for hydrogen(H2)as one of the important reactions has getting more and more attention in these years.Herein,we synthesized a series of Mo,N,and ...In view of recent environmental concerns,electrochemical water splitting for hydrogen(H2)as one of the important reactions has getting more and more attention in these years.Herein,we synthesized a series of Mo,N,and P co-doped carbons as efficient electrocatalysts to replace the expensive platinum-based catalysts.As the final products,the combination of Mo_(2)C nanoparticles(NPs)and N,P co-doped carbons were fabricated using a simple molten salt process.More notably,KCl as the template could be recycled and reused via water washing.The ratios of the precursors could affect the structure of the final production,and therefore further determine the performance of electrocatalytic towards hydrogen evolution reaction(HER).Owing to extensive supplies of active sites and heterogeneous structures that provide transfer channels for electrons,the optimal sample of GUPMo-2.00KCl exhibited the best HER activity among the as-synthesized samples,including low overpotentials,small Tafel slope,and good stability.This work opens up a novel prospect for the designing of high-performance electrocatalysts.展开更多
基金Project (2005CB623703) supported by the Major State Basic Research and Development Program of ChinaProject (2008AA030502) supported by the National High-Tech Research and Development Program of China
文摘Pitch and TiB2/C green composite cathode material were respectively analyzed with simultaneous DSC-TGA, and effects of three baking processes of TiB2/C composite cathode material, i.e. K25, K5 and M5, on properties of TiB2/C composite cathode material were investigated. The results show that thermogravimetrie behavior of pitch and TiB2/C green composite cathode is similar, and appears the largest mass loss rate in the temperature range from 200 to 600 ℃. The bulk density variation of sample K5 before and after baking is the largest （11.9%）, that of sample K25 is the second, and that of sample M5 is the smallest （6.7%）. The crushing strength of sample M5 is the biggest （51.2 MPa）, that of sample K2.5 is the next, and that of sample K5 is the smallest （32.8 MPa）. But, the orders of the electrical resistivity and electrolysis expansion of samples are just opposite with the order of crushing strength. The heating rate has a great impact on the microstructure of sample. The faster the heating rate is, the bigger the pore size and porosity of sample are. Compared with the heating rate between 200 and 600℃ of samples K25 and K5, that of sample M5 is slower and suitable for baking process of TiB2/C composite cathode material.
基金supported by the National Natural Science Foundation of China(No.21376251 and 21406233)the National Basic Research Development Program of China(2013CB632600)
文摘Hierarchical mesoporous MoO2/Mo2C/C microspheres,which are composed of primary nanoparticles with a size of about 30 nm,have been designed and synthesized through polymer regulation and subsequent carbonization processes.The as-synthesized microspheres were characterized by XRD,Raman,SEM,TEM,XPS measurements and so on.It was found that polyethylene glycol acted as a structure-directing agent,mild reducing agent and carbon source in the formation of these hierarchical mesoporous Mo O2/Mo2C/C microspheres.Moreover,the electrochemical property of the microspheres was also investigated in this work.Evaluated as an anode material for lithium ion batteries,the hierarchical mesoporous Mo O2/Mo2C/C electrode delivered the discharge specific capacities of 665 and 588 m Ah/g after 100 cycles at current densities of 100 and 200 m A/g,respectively.The satisfactory cycling performance and controllable process facilitate the practical applications of the hierarchical mesoporous Mo O2/Mo2C/C as a potential anode material in high-energy density lithium-ion batteries.
文摘通过溶剂热法制备了球状C-TiO_(2)催化剂以及BiOCl/C-TiO_(2)复合光催化材料。与纯TiO_(2)相比,球状C-TiO_(2)和BiOCl/C-TiO_(2)的禁带宽度显著降低。以亚甲基蓝为降解目标,当染料质量浓度为25 mg/L、pH为7时,0.1 g BiOCl/CTiO_(2)对其的降解率在1 h可达到81.44%,催化效率达64.15%,其动力学过程符合一级动力学模型。
基金supported by the National Key R&D Program of China(Grant No.2023YFB3710601)the National Natural Science Foundation of China(Grant Nos.52203385 and 52171056)+2 种基金the CNNC Science Fund for Talented Young Scholars,the Institute of Metal Research(IMR)Innovation Fund(Grant No.2021-ZD02)the Natural Science Foundation of Liaoning Province(Grant No.2022-BS-009)Young Elite Scientists Sponsorship Program by CAST(Grant No.YESS20220225).
文摘B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel.In order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder surface.In this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al composites.It was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high temperature.As the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased significantly.The finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.
基金supported by the National Natural Science Foundation of China(No.22272111)the Major Project Incubation Project of Shenyang Normal University,China(No.ZD202103)the Fundamental Research Funds for the Liaoning Universities,China.
文摘In view of recent environmental concerns,electrochemical water splitting for hydrogen(H2)as one of the important reactions has getting more and more attention in these years.Herein,we synthesized a series of Mo,N,and P co-doped carbons as efficient electrocatalysts to replace the expensive platinum-based catalysts.As the final products,the combination of Mo_(2)C nanoparticles(NPs)and N,P co-doped carbons were fabricated using a simple molten salt process.More notably,KCl as the template could be recycled and reused via water washing.The ratios of the precursors could affect the structure of the final production,and therefore further determine the performance of electrocatalytic towards hydrogen evolution reaction(HER).Owing to extensive supplies of active sites and heterogeneous structures that provide transfer channels for electrons,the optimal sample of GUPMo-2.00KCl exhibited the best HER activity among the as-synthesized samples,including low overpotentials,small Tafel slope,and good stability.This work opens up a novel prospect for the designing of high-performance electrocatalysts.
