The pursuit of advanced sodium-ion batteries(SIBs)has been intensified due to the escalating demand for sustainable energy storage solutions.A W-doped P2-type layered cathode material,Na_(0.67)Ni_(0.246)W_(0.004)Mn_(0...The pursuit of advanced sodium-ion batteries(SIBs)has been intensified due to the escalating demand for sustainable energy storage solutions.A W-doped P2-type layered cathode material,Na_(0.67)Ni_(0.246)W_(0.004)Mn_(0.75)O_(2)(NNWMO),has been developed to address the limitations of traditional cathode materials.Compared to the pristine Na_(0.67)Ni_(0.25)Mn_(0.75)O_(2)(NNMO),NNWMO exhibits improved reversible capacity,excellent cycle performance,and remarkable rate performance.It can deliver an increased discharge capacity of 142.20 mAh/g at 0.1 C,with an admirable capacity retention of 80.5% after 100 cycles at high voltage.In situ XRD results demonstrate that the rivet effect related to the strong W—O bonds inhibits irreversible phase transition and enhances structural reversibility during charge/discharge processes.High-resolution scanning transmission electron microscopy and X-ray diffraction results confirm successful lattice doping of W^(6+)and increased layer spacing,contributing to favorable sodium ion diffusion kinetics.Density-functional theory(DFT)calculation results further reveal that the smoother Na+ion diffusion dynamics is attributed to the reduced migration energy barrier of Na^(+)with the insertion of W^(6+).This study provides valuable insights into the design of high-performance cathode materials for next-generation SIBs,showcasing the potential for more efficient,stable,and enduring energy storage solutions.展开更多
The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped mat...The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped materials. In this work, the synthesis of doped brookite, a typical meta-stable phase of TiO2, has been explored novelly by in-situ adding of cations of VIIIB and IB,IIB elements in the 3rd period（Fe, Co, Ni, Cu, Zn） during the urea-lactate aided low-basicity hydrothermal process. The results showed that only Cu-doped brookite could be successfully synthesized with trace amount of copper intensively internalized into the brookite lattice, while the other dopants lead to the formation of anatase TiO2. Extensive characterizations indicated a two-step doping process, where copper ions were firstly dispersed in an amorphous layer on the lattice surface and then they were internalized into brookite lattice. Cu-doped brookite exhibited significantly enhanced photocatalytic activity in the phenol degradation under visible light compared to bare brookite. The enhancement of catalytic performance was assigned to the impurity band gap and the reduction of charge carriers＇ recombination introduced by the internalization of Cu ions. The investigation reported herein contributes to the understanding of complex ion-doping effects on the structures of meta-stable materials, and provides hints for obtaining other functional doped materials.展开更多
Lattice‐doping and surface decoration are prospective routes to improve the visible‐light photocatalytic ability of TiO2,but the two techniques are difficult to combine into one preparation process because they are ...Lattice‐doping and surface decoration are prospective routes to improve the visible‐light photocatalytic ability of TiO2,but the two techniques are difficult to combine into one preparation process because they are usually conducted under different conditions,which limits the efficiency of TiO2 modification.In this study,TiO2 was successfully modified by simultaneous lattice‐doping and surface decoration,and the visible‐light photocatalytic capacity was largely improved.Upon comparing the method reported here with previous ones,the most significant difference is that Fe(II)‐phenanthroline was first used as the co‐precursor of the introduced elements of C,N,and Fe.These three elements were simultaneously introduced to TiO2 at high levels by this co‐precursor method.The as‐synthesized photocatalysts were systemically investigated and analyzed by several characterization methods such as XRD,FT‐IR,XPS,Raman spectroscopy,EPR,UV‐Vis DRS,photoluminescence spectra,photocurrent,electrochemical impedance spectra,TEM,and HRTEM.The photocatalytic degradation of 4‐NP under visible‐light irradiation was used to evaluate the photocatalytic activity of the photocatalysts.Based on the experimental data,a probable mechanism for the photocatalytic degradation by the photocatalysts is proposed.This is a novel method of using one source to simultaneously introduce metal and non‐metal elements to TiO2 at high levels,which may provide a new way to prepare highly effective TiO2 photocatalysts.展开更多
A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustio...A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustion under loose contact condition.XRD and STEM mapping results confirm that all the secondary metal cations have entered the lattice matrix of tetragonal rutile SnO2 to form non‐continuous solid solutions,thus impeding crystallization and improving the surface areas and pore volumes of the modified catalysts.In comparison with regular SnO2 nanoparticles,the 3DOM SnO2 displays evidently improved activity,testifying that the formation of the 3DOM structure can anchor the soot particulates in the macro‐pores,which ensures that the contact of the soot particles with the active sites on the 3DOM skeleton is more easily formed,thus benefiting the target reaction.With the incorporation of the secondary metal cations,the activity of the catalyst can be further improved due to the formation of more abundant mobile oxygen species.In summary,these effects are believed to be the major factors responsible for the activity of the catalyst.展开更多
With the shortage of lithium resources,sodiumion batteries(SIBs)are considered one of the most promising candidates for lithium-ion batteries.P2-type and O3-type layered oxides are one of the few cathodes that can acc...With the shortage of lithium resources,sodiumion batteries(SIBs)are considered one of the most promising candidates for lithium-ion batteries.P2-type and O3-type layered oxides are one of the few cathodes that can access high energy density.However,they usually exhibit structural change,capacity decay,and slow Na ion kinetic.Herein,we present layered ternary-phase cathodes with P2,P3 and O3 phases by a lattice doping strategy,which is demonstrated by X-ray diffraction(XRD)refinement.Combining the characteristics of P2,P3 and O3 phases,the layered composites show performance improvement during long-term battery cycling.In particular,Na_(0.7)Li_(0.1)Co_(0.3-)Fe_(0.3)Mn_(0.3)O_(2)(NLCFM)delivers a reversible capacity of120.1 mAh·g^(-1)at 0.1C(1.0C=175 mA·g^(-1))with a superior capacity retention of 72.5%after 1000 cycles at10.0C.This work offers insights into the development of advanced cathode materials for SIBs.展开更多
Silica aerogel was prepared by a sol-gel method with combination of freeze drying.The aerogel was filled with TiCl4 in autoclave and used to fabricate a hierarchical structure of TiO_(2) nanofiber shell and SiO_(2) ae...Silica aerogel was prepared by a sol-gel method with combination of freeze drying.The aerogel was filled with TiCl4 in autoclave and used to fabricate a hierarchical structure of TiO_(2) nanofiber shell and SiO_(2) aerogel core(SiO_(2)@TiO_(2)).The TiO_(2) nanofibers with a diameter of 10-15 nm were highly crystalline and mainly grew along the(101)or(001)planes,favoring charge migration along the growth axis of the fibers.The photoluminescence(PL)emission spectra show that the TiO_(2) nanofibers exhibited much lower PL intensity than P25.The free standing TiO2 nanofibers loaded with CuO had a band gap of 3.04 eV.When CuO was hierarchically loaded on the nanofiber surface and into the aerogel core(SiO_(2)/CuO@TiO_(2)/CuO),the absorption edge significantly red shifted,and the band gap was further narrowed to 2.66 eV.Meanwhile,Fe^(3+)implanted TiO_(2) nanofibers on the aerogel surface(SiO_(2)@Fe-TiO_(2))were also fabricated in the same strategy.The CuO loaded nanofibers(SiO_(2)/CuO@Fe-TiO_(2)/CuO)had a band gap of 2.62 eV.The photocatalytic reduction of CO_(2) was performed under light irradiation by a 300 W Xe-lamp for 4 h.The methanol yield over the SiO_(2)/CuO@Fe-TiO_(2)/CuO reached~2,400 μmol·gcat^(-1) in the absence of sacrificial agent.展开更多
基金supported by the Talent Recruitment Program of Sichuan University of Science and Engineering(2023RC06)the Innovation Center for Chenguang High-Performance Fluorine Material(SCFY2207)+3 种基金the Key Laboratories of Fine Chemicals and Surfactants in Sichuan Provincial Universities(2022JXY04)College Students Innovation and Entrepreneurship Training Program(S20221062208,S202010622054)the Scientific Research and Innovation Team Program of Sichuan University of Science and Engineering(SUSE652B008)the Central Government Guide Local Science and Technology Development Fund(24ZYTXJS0055).
文摘The pursuit of advanced sodium-ion batteries(SIBs)has been intensified due to the escalating demand for sustainable energy storage solutions.A W-doped P2-type layered cathode material,Na_(0.67)Ni_(0.246)W_(0.004)Mn_(0.75)O_(2)(NNWMO),has been developed to address the limitations of traditional cathode materials.Compared to the pristine Na_(0.67)Ni_(0.25)Mn_(0.75)O_(2)(NNMO),NNWMO exhibits improved reversible capacity,excellent cycle performance,and remarkable rate performance.It can deliver an increased discharge capacity of 142.20 mAh/g at 0.1 C,with an admirable capacity retention of 80.5% after 100 cycles at high voltage.In situ XRD results demonstrate that the rivet effect related to the strong W—O bonds inhibits irreversible phase transition and enhances structural reversibility during charge/discharge processes.High-resolution scanning transmission electron microscopy and X-ray diffraction results confirm successful lattice doping of W^(6+)and increased layer spacing,contributing to favorable sodium ion diffusion kinetics.Density-functional theory(DFT)calculation results further reveal that the smoother Na+ion diffusion dynamics is attributed to the reduced migration energy barrier of Na^(+)with the insertion of W^(6+).This study provides valuable insights into the design of high-performance cathode materials for next-generation SIBs,showcasing the potential for more efficient,stable,and enduring energy storage solutions.
基金Financially supported by the Science and Technology Programs from Fujian Province(No.2013H0057)
文摘The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped materials. In this work, the synthesis of doped brookite, a typical meta-stable phase of TiO2, has been explored novelly by in-situ adding of cations of VIIIB and IB,IIB elements in the 3rd period（Fe, Co, Ni, Cu, Zn） during the urea-lactate aided low-basicity hydrothermal process. The results showed that only Cu-doped brookite could be successfully synthesized with trace amount of copper intensively internalized into the brookite lattice, while the other dopants lead to the formation of anatase TiO2. Extensive characterizations indicated a two-step doping process, where copper ions were firstly dispersed in an amorphous layer on the lattice surface and then they were internalized into brookite lattice. Cu-doped brookite exhibited significantly enhanced photocatalytic activity in the phenol degradation under visible light compared to bare brookite. The enhancement of catalytic performance was assigned to the impurity band gap and the reduction of charge carriers＇ recombination introduced by the internalization of Cu ions. The investigation reported herein contributes to the understanding of complex ion-doping effects on the structures of meta-stable materials, and provides hints for obtaining other functional doped materials.
基金supported by the National Natural Science Foundation of China(51368044,51568051,51668046)the National Science Fund for Excellent Young Scholars(51422807)+6 种基金the Science and Technology Supporting Program of Jiangxi Province(20151BBG70018)the Natural Science Foundation of Jiangxi Province for Distinguished Young Scholars(20162BCB23041)the Science Foundation for Young Scientists of Jiangxi Province-Key Project(20171ACB21034)the Science and Technology Project of Jiangxi Provincial Education Department(GJJ160700)the Natural Science Foundation of Jiangxi Province(20161BAB216102)the Jiangxi Province Educational Reform Project(JXJG-16-8-7)the Nanchang Hangkong University Educational Reform Project(JY1604,JY1605,KCPY-1511)~~
文摘Lattice‐doping and surface decoration are prospective routes to improve the visible‐light photocatalytic ability of TiO2,but the two techniques are difficult to combine into one preparation process because they are usually conducted under different conditions,which limits the efficiency of TiO2 modification.In this study,TiO2 was successfully modified by simultaneous lattice‐doping and surface decoration,and the visible‐light photocatalytic capacity was largely improved.Upon comparing the method reported here with previous ones,the most significant difference is that Fe(II)‐phenanthroline was first used as the co‐precursor of the introduced elements of C,N,and Fe.These three elements were simultaneously introduced to TiO2 at high levels by this co‐precursor method.The as‐synthesized photocatalysts were systemically investigated and analyzed by several characterization methods such as XRD,FT‐IR,XPS,Raman spectroscopy,EPR,UV‐Vis DRS,photoluminescence spectra,photocurrent,electrochemical impedance spectra,TEM,and HRTEM.The photocatalytic degradation of 4‐NP under visible‐light irradiation was used to evaluate the photocatalytic activity of the photocatalysts.Based on the experimental data,a probable mechanism for the photocatalytic degradation by the photocatalysts is proposed.This is a novel method of using one source to simultaneously introduce metal and non‐metal elements to TiO2 at high levels,which may provide a new way to prepare highly effective TiO2 photocatalysts.
基金the Natural Science Foundation of China(21567016,21503106)the Natural Science Foundation of Jiangxi Province(20171BAB213013)+3 种基金the Education Department Foundation of Jiangxi Province(KJLD14005)National Key Research and Development Program of China(2016YFC0209302)the Innovation Fund Designated for Graduate Students of Jiangxi Province(YC2015-B017)the Innovation Fund Designated for Undergraduate Students of China(201701035)~~
文摘A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustion under loose contact condition.XRD and STEM mapping results confirm that all the secondary metal cations have entered the lattice matrix of tetragonal rutile SnO2 to form non‐continuous solid solutions,thus impeding crystallization and improving the surface areas and pore volumes of the modified catalysts.In comparison with regular SnO2 nanoparticles,the 3DOM SnO2 displays evidently improved activity,testifying that the formation of the 3DOM structure can anchor the soot particulates in the macro‐pores,which ensures that the contact of the soot particles with the active sites on the 3DOM skeleton is more easily formed,thus benefiting the target reaction.With the incorporation of the secondary metal cations,the activity of the catalyst can be further improved due to the formation of more abundant mobile oxygen species.In summary,these effects are believed to be the major factors responsible for the activity of the catalyst.
基金financially supported by Guangxi Natural Science Foundation(No.2021GXNSFDA075012)the National Natural Science Foundation of China(Nos.U20A20249 and 22169004)+2 种基金the Natural Science Fund of Huanggang Normal University for Young Scholars(No.2014019203)the Special Fund for Guangxi Distinguished Expertthe Innovation Project of Guangxi Graduate Education(No.JGY2022031)。
文摘With the shortage of lithium resources,sodiumion batteries(SIBs)are considered one of the most promising candidates for lithium-ion batteries.P2-type and O3-type layered oxides are one of the few cathodes that can access high energy density.However,they usually exhibit structural change,capacity decay,and slow Na ion kinetic.Herein,we present layered ternary-phase cathodes with P2,P3 and O3 phases by a lattice doping strategy,which is demonstrated by X-ray diffraction(XRD)refinement.Combining the characteristics of P2,P3 and O3 phases,the layered composites show performance improvement during long-term battery cycling.In particular,Na_(0.7)Li_(0.1)Co_(0.3-)Fe_(0.3)Mn_(0.3)O_(2)(NLCFM)delivers a reversible capacity of120.1 mAh·g^(-1)at 0.1C(1.0C=175 mA·g^(-1))with a superior capacity retention of 72.5%after 1000 cycles at10.0C.This work offers insights into the development of advanced cathode materials for SIBs.
基金The authors acknowledgement the financial supports from the Key R&D Planning Project of Hainan Province(No.ZDYF2020015)the Research Lab Construction of Hainan University(No.ZY2019HN09)the National Natural Science Foundation of China(No.51761010).
文摘Silica aerogel was prepared by a sol-gel method with combination of freeze drying.The aerogel was filled with TiCl4 in autoclave and used to fabricate a hierarchical structure of TiO_(2) nanofiber shell and SiO_(2) aerogel core(SiO_(2)@TiO_(2)).The TiO_(2) nanofibers with a diameter of 10-15 nm were highly crystalline and mainly grew along the(101)or(001)planes,favoring charge migration along the growth axis of the fibers.The photoluminescence(PL)emission spectra show that the TiO_(2) nanofibers exhibited much lower PL intensity than P25.The free standing TiO2 nanofibers loaded with CuO had a band gap of 3.04 eV.When CuO was hierarchically loaded on the nanofiber surface and into the aerogel core(SiO_(2)/CuO@TiO_(2)/CuO),the absorption edge significantly red shifted,and the band gap was further narrowed to 2.66 eV.Meanwhile,Fe^(3+)implanted TiO_(2) nanofibers on the aerogel surface(SiO_(2)@Fe-TiO_(2))were also fabricated in the same strategy.The CuO loaded nanofibers(SiO_(2)/CuO@Fe-TiO_(2)/CuO)had a band gap of 2.62 eV.The photocatalytic reduction of CO_(2) was performed under light irradiation by a 300 W Xe-lamp for 4 h.The methanol yield over the SiO_(2)/CuO@Fe-TiO_(2)/CuO reached~2,400 μmol·gcat^(-1) in the absence of sacrificial agent.
