含钛高炉渣中钛组分弥散分布于多种矿物相中 ,很难直接用选矿方法分离。在高炉渣中加入 Ca O和 Mn O可使钛富集于充分结晶长大的钙钛矿相中 ,为选矿分离创造必要条件。作者借助多视场图像分析及粘度测定研究了 Ca O、Mn O对钙钛矿相结...含钛高炉渣中钛组分弥散分布于多种矿物相中 ,很难直接用选矿方法分离。在高炉渣中加入 Ca O和 Mn O可使钛富集于充分结晶长大的钙钛矿相中 ,为选矿分离创造必要条件。作者借助多视场图像分析及粘度测定研究了 Ca O、Mn O对钙钛矿相结晶的影响。实验结果表明 :Ca O加入量对钙钛矿结晶及晶体生长有双重影响。加入适量 Ca O,有利于钙钛矿相结晶量的增加 ,但 Ca O加入量过多 ,使熔渣粘度及熔化性温度显著提高 ,反而抑制钙钛矿结晶长大。加入适量 Mn O可显著降低熔渣粘度及熔化性温度 ,促进钙钛矿结晶长大。随 Ca O加入量提高 ,钙钛矿由粗大的树枝晶转变为细小等轴晶 ,说明加入过多 Ca O不利于钙钛矿晶体粗化。展开更多
La1-x Cax MnO3 （x=0-0.3） perovskite-type oxides were synthesized by citrate sol-gel method. The physical and chemical properties were characterized by X-ray diffraction （XRD）, Brumauer-Emmett-Teller method （BET）...La1-x Cax MnO3 （x=0-0.3） perovskite-type oxides were synthesized by citrate sol-gel method. The physical and chemical properties were characterized by X-ray diffraction （XRD）, Brumauer-Emmett-Teller method （BET）, X-ray photoelectron spectroscopy （XPS）, NO＋O2 -TPD （temperature-programmed desorption）, activated oxygen evaluation and H2 -TPR （temperature-programmed reduction） technologies. The results showed that NO catalytic oxidation activity was significantly improved by Ca substitution, especially for lower temperature activity. The La0.9 Ca0.1 MnO 3 sample showed the maximum conversion of 82% at 300 oC. The monodentate nitrates played a crucial role for the formation of NO2 . The reducibility of Mn 4＋ ions and reactivity of activated oxygen were favorable for the catalytic performances of NO oxidation.展开更多
As a promising candidate for next generation energy storage devices, lithium sulfur (Li-S) batteries still confrant rapid capacity degradation and low rate capability. Herein, we report a well-architected porous nitro...As a promising candidate for next generation energy storage devices, lithium sulfur (Li-S) batteries still confrant rapid capacity degradation and low rate capability. Herein, we report a well-architected porous nitrogen-doped carbon/MnO coaxial nanotubes (MnO@PNC) as an efficient sulfur host material. The host shows excellent electron conductivity, sufficient ion transport channels and strong adsorption capability for the polysulfides, resulting from the abundant nitrogen-doped sites and pores as well as MnO in the carbon shell of MnO@PNC. The MnO@PNC-S composite electrode with a sulfur content of 75 wt.% deliveries a specific capacity of 802 mAh·g^-1 at a high rate of 5.0C and outstanding cycling stability with a capacity retention of 82% after 520 cycles at 1.0C.展开更多
In recent years, coesite-bearing eclogites have been discovered at many sites in the eastern part of the Qinling-Dabie Orogene. However, these ultrahigh-pressure metamorphic rocks were found only in the southern Qinli...In recent years, coesite-bearing eclogites have been discovered at many sites in the eastern part of the Qinling-Dabie Orogene. However, these ultrahigh-pressure metamorphic rocks were found only in the southern Qinling Orogene before. In 1993, they were reported in the Qinling Group. Recently, coesites have been found in eclogites.展开更多
Development of cheap,abundant and noblemetal-free materials as high efficient oxygen reduction electrocatalysts is crucial for future energy storage system. Here,one-dimensional（1D） MnO N-doped carbon nanofibers（Mn...Development of cheap,abundant and noblemetal-free materials as high efficient oxygen reduction electrocatalysts is crucial for future energy storage system. Here,one-dimensional（1D） MnO N-doped carbon nanofibers（MnO-NCNFs） were successfully developed by electrospinning combined with high temperature pyrolysis. The MnO-NCNFs exhibit promising electrochemical performance,methanol tolerance,and durability in alkaline medium. The outstanding electrocatalytic activity is mainly attributed to several issues.First of all,the uniform 1D fiber structure and the conductive network could facilitate the electron transport. Besides,the introduction of Mn into the precursor can catalyze the transformation of amorphous carbon to graphite carbon,while the improved graphitization means better conductivity,beneficial for the enhancement of catalytic activity for oxygen reduction reaction（ORR）. Furthermore,the porous structure and high surface area can effectively decrease the mass transport resistance and increase the exposed ORR active sites,thus improve utilization efficiency and raise the quantity of exposed ORR active sites. The synergistic effect of MnO and NCNFs matrix,which enhances charge transfer,adsorbent transport,and delivers efficiency in the electrolyte solution,ensures the high ORR performance of MnO-NCNFs.展开更多
Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the d...Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.展开更多
文摘含钛高炉渣中钛组分弥散分布于多种矿物相中 ,很难直接用选矿方法分离。在高炉渣中加入 Ca O和 Mn O可使钛富集于充分结晶长大的钙钛矿相中 ,为选矿分离创造必要条件。作者借助多视场图像分析及粘度测定研究了 Ca O、Mn O对钙钛矿相结晶的影响。实验结果表明 :Ca O加入量对钙钛矿结晶及晶体生长有双重影响。加入适量 Ca O,有利于钙钛矿相结晶量的增加 ,但 Ca O加入量过多 ,使熔渣粘度及熔化性温度显著提高 ,反而抑制钙钛矿结晶长大。加入适量 Mn O可显著降低熔渣粘度及熔化性温度 ,促进钙钛矿结晶长大。随 Ca O加入量提高 ,钙钛矿由粗大的树枝晶转变为细小等轴晶 ,说明加入过多 Ca O不利于钙钛矿晶体粗化。
基金Project supported by National High Technology Research and Development Program of China(863Program,2011AA03A405)
文摘La1-x Cax MnO3 （x=0-0.3） perovskite-type oxides were synthesized by citrate sol-gel method. The physical and chemical properties were characterized by X-ray diffraction （XRD）, Brumauer-Emmett-Teller method （BET）, X-ray photoelectron spectroscopy （XPS）, NO＋O2 -TPD （temperature-programmed desorption）, activated oxygen evaluation and H2 -TPR （temperature-programmed reduction） technologies. The results showed that NO catalytic oxidation activity was significantly improved by Ca substitution, especially for lower temperature activity. The La0.9 Ca0.1 MnO 3 sample showed the maximum conversion of 82% at 300 oC. The monodentate nitrates played a crucial role for the formation of NO2 . The reducibility of Mn 4＋ ions and reactivity of activated oxygen were favorable for the catalytic performances of NO oxidation.
基金the National Natural Science Fund for Distinguished Young Scholars (No. 51425204)the National Natural Science Foundation of China (Nos. 51521001 and 51702247)+2 种基金the National Key Research and Development Program of China (No. 2016YFA0202603)the Programme of Introducing Talents of Discipline to Universities (No. B17034)the Fundamental Research Funds for the Central Universities (WUT: 2016111001, 2017111009, 2017111005, 2017111030).
文摘As a promising candidate for next generation energy storage devices, lithium sulfur (Li-S) batteries still confrant rapid capacity degradation and low rate capability. Herein, we report a well-architected porous nitrogen-doped carbon/MnO coaxial nanotubes (MnO@PNC) as an efficient sulfur host material. The host shows excellent electron conductivity, sufficient ion transport channels and strong adsorption capability for the polysulfides, resulting from the abundant nitrogen-doped sites and pores as well as MnO in the carbon shell of MnO@PNC. The MnO@PNC-S composite electrode with a sulfur content of 75 wt.% deliveries a specific capacity of 802 mAh·g^-1 at a high rate of 5.0C and outstanding cycling stability with a capacity retention of 82% after 520 cycles at 1.0C.
基金Project supported by the National Natural Science Foundation of China
文摘In recent years, coesite-bearing eclogites have been discovered at many sites in the eastern part of the Qinling-Dabie Orogene. However, these ultrahigh-pressure metamorphic rocks were found only in the southern Qinling Orogene before. In 1993, they were reported in the Qinling Group. Recently, coesites have been found in eclogites.
基金supported by the National Natural Science Foundation of China (21671096 and 21603094)the Natural Science Foundation of Guangdong Province (2016A030310376)+2 种基金Shenzhen Key Laboratory Project (ZDSYS201603311013489)the Natural Science Foundation of Shenzhen (JCYJ20150630145302231 and JCYJ20150331101823677)the Undergraduate Training Program for Innovation and Entrepreneurship of Guangdong (2016S10)
文摘Development of cheap,abundant and noblemetal-free materials as high efficient oxygen reduction electrocatalysts is crucial for future energy storage system. Here,one-dimensional（1D） MnO N-doped carbon nanofibers（MnO-NCNFs） were successfully developed by electrospinning combined with high temperature pyrolysis. The MnO-NCNFs exhibit promising electrochemical performance,methanol tolerance,and durability in alkaline medium. The outstanding electrocatalytic activity is mainly attributed to several issues.First of all,the uniform 1D fiber structure and the conductive network could facilitate the electron transport. Besides,the introduction of Mn into the precursor can catalyze the transformation of amorphous carbon to graphite carbon,while the improved graphitization means better conductivity,beneficial for the enhancement of catalytic activity for oxygen reduction reaction（ORR）. Furthermore,the porous structure and high surface area can effectively decrease the mass transport resistance and increase the exposed ORR active sites,thus improve utilization efficiency and raise the quantity of exposed ORR active sites. The synergistic effect of MnO and NCNFs matrix,which enhances charge transfer,adsorbent transport,and delivers efficiency in the electrolyte solution,ensures the high ORR performance of MnO-NCNFs.
文摘Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.
