Themanganese-cobalt mixed oxide nanorodswere fabricated using a hydrothermalmethod with different metal precursors(KMnO_(4)and MnSO_(4)·H_(2)O for MnOx and Co(NO3)2>6H_(2)O and CoCl_(2)>6H_(2)O for Co_(3)O_...Themanganese-cobalt mixed oxide nanorodswere fabricated using a hydrothermalmethod with different metal precursors(KMnO_(4)and MnSO_(4)·H_(2)O for MnOx and Co(NO3)2>6H_(2)O and CoCl_(2)>6H_(2)O for Co_(3)O_(4)).Bamboo-like MnO_(2)>Co_(3)O_(4)(B-MnO_(2)>Co_(3)O_(4)(S))was derived from repeated hydrothermal treatments with Co_(3)O_(4)@MnO_(2)and MnSO_(4)>H_(2)O,whereas Co_(3)O_(4)@MnO_(2)nanorods were derived from hydrothermal treatment with Co_(3)O_(4)nanorods and KMnO_(4).The study shows that manganese oxide was tetragonal,while the cobalt oxide was found to be cubic in the crystalline arrangement.Mn surface ions were present in multiple oxidation states(e.g.,Mn^(4+)and Mn^(3+))and surface oxygen deficiencies.The content of adsorbed oxygen species and reducibility at low temperature declined in the sequence of BMnO_(2)>Co_(3)O_(4)(S)>Co_(3)O_(4)@MnO_(2)>MnO_(2)>Co_(3)O_(4),matching the changing trend in activity.Among all the samples,B-MnO_(2)>Co_(3)O_(4)(S)showed the preeminent catalytic performance for the oxidation of toluene(T10%=187℃,T50%=276℃,and T90%=339℃).In addition,the B-MnO_(2)>Co_(3)O_(4)(S)sample also exhibited good H_(2)O^(-),CO_(2)^(-),and SO_(2)^(-)resistant performance.The good catalytic performance of B-MnO_(2)>Co_(3)O_(4)(S)is due to the high concentration of adsorbed oxygen species and good reducibility at low temperature.Toluene oxidation over B-MnO_(2)>Co_(3)O_(4)(S)proceeds through the adsorption of O_(2)and toluene to form O∗,OH∗,and H_(2)C(C6H5)∗species,which then react to produce benzyl alcohol,benzoic acid,and benzaldehyde,ultimately converting to CO_(2)and H_(2)O.The findings suggest that B-MnO_(2)>Co_(3)O_(4)(S)has promising potential for use as an effective catalyst in practical applications.展开更多
The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structu...The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structure, while the Er deuteride film was observed as bamboo-like morphology. The in-situ X-ray diffraction results demonstrate that the diffraction peaks of 27.39°, 28.43°, 31.71°, and 39.95° are ascribed to the crystal planes of （002）, （110）, （111）, and （112） of ErD3 phase, respectively. It is also confirmed that by in-situ X-ray diffraction technique, ErD3 grains would be dissociated at temperature exceeding 400 ℃. This result is consistent with the conclusion obtained by thermal desorption spectroscopy.展开更多
Carbon nanotubes(CNTs)have been far and wide employed as the counter electrodes(CEs)in dyesensitized solar cells because of their individual physical and chemical properties.However,the techniques available now,such a...Carbon nanotubes(CNTs)have been far and wide employed as the counter electrodes(CEs)in dyesensitized solar cells because of their individual physical and chemical properties.However,the techniques available now,such as chemical vapor deposition,arc discharge and laser ablation for synthesizing CNTs,commonly suffer from rigorous operations and complicated steps,which make the process difficult to be controlled.Herein,we present a simple and facile glutamic acid-assisted hydrothermal recrystallization strategy to construct bamboo-like CNTs(GHP-BC-x).Generally,the conventional organic dye3,4,9,10-perylene tetracarboxylic dianhydride(PTCDA)is used as a precursor and glutamic acid efficiently promotes the recrystallization of the perylene cores'planarπ-conjugated system in PTCDA under hydrothermal conditions and then self-assembles into one-dimensio nal nano rods with improved crystallization degree,finally resulting in the morphology of bamboo-like CNTs after carbonization.When applied as the counter electrodes,the GHP-BC-3 displays a remarkable power conversion efficiency of8.25%,benefiting from the superb electrical conductivity and mass transfer dynamics,superior to that of Pt CE(7.62%).展开更多
In this work,a novel bamboo-like carbon nanotubes@Sn4P3@carbon(BLCNTs@Sn_(4)P_(3)@C)coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process.The prepar...In this work,a novel bamboo-like carbon nanotubes@Sn4P3@carbon(BLCNTs@Sn_(4)P_(3)@C)coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process.The prepared Sn_(4)P_(3) nanoparticles are uniformly coated and wrapped on the one-dimensional(1D)bamboo-like CNTs,which is covered by a uniform carbon layer to form a sandwich-like structure with Sn_(4)P_(3) in between.The inner CNT and outer carbon can effectively maintain the structural stability and serve as the good electron conductors.Additionally,the outer carbon coating layer can effectively keep BLCNTs@Sn_(4)P_(3)@C nanotubes separate each other,preventing aggregation of Sn_(4)P_(3) during charge/discharge when this material is used as anode for sodium ion batteries.The anode of BLCNTs@Sn_(4)P_(3)@C shows excellent reversible capacity and a long cycling of over 2000 cycles.The unique design of coaxial nanotubes is greatly beneficial to the electrochemical performance of Sn_(4)P_(3) for sodium ion storage.展开更多
A molecular structural mechanics approach combining with finite element analysis(MSM/FEA) was applied to study the microstructure and tensile behaviors of bamboo-like carbon nanotubes(BCNTs). The mathematical model of...A molecular structural mechanics approach combining with finite element analysis(MSM/FEA) was applied to study the microstructure and tensile behaviors of bamboo-like carbon nanotubes(BCNTs). The mathematical model of tensile behaviors of BCNTs was established based on molecular structural mechanics theory. The deformations of BCNTs, with different diameters and compartments set based on the experimental investigation on BCNT structures synthesized by chemical vapor depositon, under tensile load, were analyzed with ANSYS programmed. Results show that the BCNTs have good tensile properties, and those Young's modulus can reach 0.84 Tpa. Through the analysis, it can be found that the Young's modulus of BCNTs depends on the diameters and the length of compartment, which is in good agreement with our experimental tests for the tensile performances of individual BCNT.展开更多
Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion (ECC) technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst pre...Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion (ECC) technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.展开更多
Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction(ORR).Thus,fro...Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction(ORR).Thus,from the atomic-scale engineering we develop a high intrinsic activity ORR catalyst in terms of incorporating atomically dispersed dual Fe centers(single Fe atoms and ultra-small Fe atomic clusters)into bamboo-like N-doped carbon nanotubes.Benefiting from atomically dispersed dual-Fe centers on the atomic interface of Fe-Nx/carbon nanotubes,the fabricated dual Fe centers catalyst exhibits an extremely high ORR activity(E_(onset)=1.006 V;E_(1/2)=0.90 V),beyond state-of-the-art Pt/C.Remarkably,this catalyst also shows a superior kinetic current density of 19.690 mA·cm^(−2),which is 7 times that of state-of-the-art Pt/C.Additionally,based on the excellent catalyst,the primary Zn-air battery reveals a high power density up to 137 mW·cm^(−2) and sufficient potential cycling stability(at least 25 h).Undoubtedly,given the unique structure–activity relationship of dual-Fe active species and metal-nitrogen-carbon substrates,the catalyst will show great prospects in highly efficient electrochemical energy conversion devices.展开更多
基金supported by the National Natural Science Foundation Committee of China-Liaoning Provincial People’s Government Joint Fund(No.U1908204)the National Natural Science Foundation of China(Nos.21876006 and 21976009)+2 种基金the Natural Science Foundation of Beijing Municipal Commission of Education(No.KM201710005004)the Development Program for the Youth Outstanding-Notch Talent of Beijing Municipal Commission of Education(No.CIT&TCD201904019)the Foundation on the Creative Research Team Construction Promotion Project of Beijing Municipal Institutions(No.IDHT20190503).
文摘Themanganese-cobalt mixed oxide nanorodswere fabricated using a hydrothermalmethod with different metal precursors(KMnO_(4)and MnSO_(4)·H_(2)O for MnOx and Co(NO3)2>6H_(2)O and CoCl_(2)>6H_(2)O for Co_(3)O_(4)).Bamboo-like MnO_(2)>Co_(3)O_(4)(B-MnO_(2)>Co_(3)O_(4)(S))was derived from repeated hydrothermal treatments with Co_(3)O_(4)@MnO_(2)and MnSO_(4)>H_(2)O,whereas Co_(3)O_(4)@MnO_(2)nanorods were derived from hydrothermal treatment with Co_(3)O_(4)nanorods and KMnO_(4).The study shows that manganese oxide was tetragonal,while the cobalt oxide was found to be cubic in the crystalline arrangement.Mn surface ions were present in multiple oxidation states(e.g.,Mn^(4+)and Mn^(3+))and surface oxygen deficiencies.The content of adsorbed oxygen species and reducibility at low temperature declined in the sequence of BMnO_(2)>Co_(3)O_(4)(S)>Co_(3)O_(4)@MnO_(2)>MnO_(2)>Co_(3)O_(4),matching the changing trend in activity.Among all the samples,B-MnO_(2)>Co_(3)O_(4)(S)showed the preeminent catalytic performance for the oxidation of toluene(T10%=187℃,T50%=276℃,and T90%=339℃).In addition,the B-MnO_(2)>Co_(3)O_(4)(S)sample also exhibited good H_(2)O^(-),CO_(2)^(-),and SO_(2)^(-)resistant performance.The good catalytic performance of B-MnO_(2)>Co_(3)O_(4)(S)is due to the high concentration of adsorbed oxygen species and good reducibility at low temperature.Toluene oxidation over B-MnO_(2)>Co_(3)O_(4)(S)proceeds through the adsorption of O_(2)and toluene to form O∗,OH∗,and H_(2)C(C6H5)∗species,which then react to produce benzyl alcohol,benzoic acid,and benzaldehyde,ultimately converting to CO_(2)and H_(2)O.The findings suggest that B-MnO_(2)>Co_(3)O_(4)(S)has promising potential for use as an effective catalyst in practical applications.
基金supported by the Fundamental Research Funds for the Central Universities of Ministry of Education of China(No.ZYGX2012YB017)the National Natural Science Foundation of China(No.91126001)
文摘The formation and dissociation of Er deuteride grains were investigated by using scanning electron microscopy, in-situ X-ray diffraction and thermal desorption spectroscopy. Pure Er film shows classic columnar structure, while the Er deuteride film was observed as bamboo-like morphology. The in-situ X-ray diffraction results demonstrate that the diffraction peaks of 27.39°, 28.43°, 31.71°, and 39.95° are ascribed to the crystal planes of （002）, （110）, （111）, and （112） of ErD3 phase, respectively. It is also confirmed that by in-situ X-ray diffraction technique, ErD3 grains would be dissociated at temperature exceeding 400 ℃. This result is consistent with the conclusion obtained by thermal desorption spectroscopy.
基金partly supported by the National Natural Science Foundation of China(51872035 and 22078052)Talent Program of Rejuvenation of the Liaoning(XLYC1807002)Innovation Program of Dalian City(2019RJ03)。
文摘Carbon nanotubes(CNTs)have been far and wide employed as the counter electrodes(CEs)in dyesensitized solar cells because of their individual physical and chemical properties.However,the techniques available now,such as chemical vapor deposition,arc discharge and laser ablation for synthesizing CNTs,commonly suffer from rigorous operations and complicated steps,which make the process difficult to be controlled.Herein,we present a simple and facile glutamic acid-assisted hydrothermal recrystallization strategy to construct bamboo-like CNTs(GHP-BC-x).Generally,the conventional organic dye3,4,9,10-perylene tetracarboxylic dianhydride(PTCDA)is used as a precursor and glutamic acid efficiently promotes the recrystallization of the perylene cores'planarπ-conjugated system in PTCDA under hydrothermal conditions and then self-assembles into one-dimensio nal nano rods with improved crystallization degree,finally resulting in the morphology of bamboo-like CNTs after carbonization.When applied as the counter electrodes,the GHP-BC-3 displays a remarkable power conversion efficiency of8.25%,benefiting from the superb electrical conductivity and mass transfer dynamics,superior to that of Pt CE(7.62%).
基金supported by National Natural Science Foundation of China(51772051,51872071)Natural Science Foundation of Guangdong Province(2016A030310127)+3 种基金Support Funding for Innovation Projects for Overseas Students in Anhui Province(2020LCX031)supported by the Foundation of High-level Talents(GB200902-30,No.196100041018)the Foundation of Regular Research Team(TDYB2019007,No.196100043028)the Foundation of Doctor'sWorkstation of MCNAIR NEW POWER CO.,LTD(GC200104-40,No.186100030017)at Dongguan University of Technology.
文摘In this work,a novel bamboo-like carbon nanotubes@Sn4P3@carbon(BLCNTs@Sn_(4)P_(3)@C)coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process.The prepared Sn_(4)P_(3) nanoparticles are uniformly coated and wrapped on the one-dimensional(1D)bamboo-like CNTs,which is covered by a uniform carbon layer to form a sandwich-like structure with Sn_(4)P_(3) in between.The inner CNT and outer carbon can effectively maintain the structural stability and serve as the good electron conductors.Additionally,the outer carbon coating layer can effectively keep BLCNTs@Sn_(4)P_(3)@C nanotubes separate each other,preventing aggregation of Sn_(4)P_(3) during charge/discharge when this material is used as anode for sodium ion batteries.The anode of BLCNTs@Sn_(4)P_(3)@C shows excellent reversible capacity and a long cycling of over 2000 cycles.The unique design of coaxial nanotubes is greatly beneficial to the electrochemical performance of Sn_(4)P_(3) for sodium ion storage.
基金Funded by the National Natural Science Foundation of China(Nos.51472203,51221001,U1435202)
文摘A molecular structural mechanics approach combining with finite element analysis(MSM/FEA) was applied to study the microstructure and tensile behaviors of bamboo-like carbon nanotubes(BCNTs). The mathematical model of tensile behaviors of BCNTs was established based on molecular structural mechanics theory. The deformations of BCNTs, with different diameters and compartments set based on the experimental investigation on BCNT structures synthesized by chemical vapor depositon, under tensile load, were analyzed with ANSYS programmed. Results show that the BCNTs have good tensile properties, and those Young's modulus can reach 0.84 Tpa. Through the analysis, it can be found that the Young's modulus of BCNTs depends on the diameters and the length of compartment, which is in good agreement with our experimental tests for the tensile performances of individual BCNT.
基金Project(KM200510772013) supported by the Science and Technology Development Program of Education Committee of Beijing City Project(2005-2007) supported by the Academic Innovative Team Porgram (Novel Sensor and Materials: Nanodevice and Nanomaterials) of Education Committee of Beijing City
文摘Bamboo-like carbon nanotubes were synthesized by ethanol catalytic combustion (ECC) technique with combustion method. Copper plate was employed as substrate, ethanol as carbon source, and iron chloride as catalyst precursor. The as-grown black powder was characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that the thinner bamboo-like carbon nanotubes have a relatively good structure that the compartment layers are more regular, while the thicker carbon nanotubes have a relatively irregular bamboo-like structure; the proposed method is simple to synthesize bamboo-like carbon nanotubes and has some advantages, such as flexible synthesis conditions, simple setup, and environment-friendly.
基金the National Natural Science Foundation of China(NSFC)(Nos.21501096 and 22075223)Natural Science Foundation of Jiangsu(Nos.BK20150086 and BK20201120)+2 种基金Foundation of the Jiangsu Education Committee(No.15KJB150020)the Six Talent Peaks Project in Jiangsu Province(No.JY-087)Innovation Project of Jiangsu Province.
文摘Interfacial atomic configuration between dual-metal active species and nitrogen-carbon substrates is of great importance for improving the intrinsic activity of catalysts toward oxygen reduction reaction(ORR).Thus,from the atomic-scale engineering we develop a high intrinsic activity ORR catalyst in terms of incorporating atomically dispersed dual Fe centers(single Fe atoms and ultra-small Fe atomic clusters)into bamboo-like N-doped carbon nanotubes.Benefiting from atomically dispersed dual-Fe centers on the atomic interface of Fe-Nx/carbon nanotubes,the fabricated dual Fe centers catalyst exhibits an extremely high ORR activity(E_(onset)=1.006 V;E_(1/2)=0.90 V),beyond state-of-the-art Pt/C.Remarkably,this catalyst also shows a superior kinetic current density of 19.690 mA·cm^(−2),which is 7 times that of state-of-the-art Pt/C.Additionally,based on the excellent catalyst,the primary Zn-air battery reveals a high power density up to 137 mW·cm^(−2) and sufficient potential cycling stability(at least 25 h).Undoubtedly,given the unique structure–activity relationship of dual-Fe active species and metal-nitrogen-carbon substrates,the catalyst will show great prospects in highly efficient electrochemical energy conversion devices.
