In this article,the Sm-doping single crystals Ca1-xSmxFe2As2（x = 0 0.2） were prepared by the Ca As flux method,and followed by a rapid quenching treatment after the high temperature growth.The samples were character...In this article,the Sm-doping single crystals Ca1-xSmxFe2As2（x = 0 0.2） were prepared by the Ca As flux method,and followed by a rapid quenching treatment after the high temperature growth.The samples were characterized by structural,resistive,and magnetic measurements.The successful Sm-substitution was revealed by the reduction of the lattice parameter c,due to the smaller ionic radius of Sm3＋than Ca2＋.Superconductivity was observed in all samples with onset Tc varying from 27 K to 44 K upon Sm-doping.The coexistence of a collapsed phase transition and the superconducting transition was found for the lower Sm-doping samples.Zero resistivity and substantial superconducting volume fraction only happen in higher Sm-doping crystals with the nominal x 〉 0.10.The doping dependences of the c-axis length and onset Tc were summarized.The high-Tc observed in these quenched crystals may be attributed to simultaneous tuning of electron carriers doping and strain effect caused by lattice reduction of Sm-substitution.展开更多
A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape whic...A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape which can increase its specific area and active sites.In SCN/MX composite,the optical properties,no matter optical absorption ability or separation performance of photo-induced electrons and holes,were enhanced.Among them,Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination,and Ti_(3)C_(2) MXene would broaden light absorption and further improve the carrier migration efficiency.The SCN/MX presented higher photocatalytic degradation efficiency(>99%)of cipro floxacin under visible light irradiation.The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes.The degradation mechanisms of ciprofloxacin(CIP)over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring,and the final products were CO_(2),H_(2)O and F^(-).展开更多
In the present work,we have synthesized samarium doped zinc oxide nanostructures(Zn1-xSmxO;x=0.00,0.02,0.04 and 0.06) via chemical precipitation method and studied their structural,morphological,optical and photocatal...In the present work,we have synthesized samarium doped zinc oxide nanostructures(Zn1-xSmxO;x=0.00,0.02,0.04 and 0.06) via chemical precipitation method and studied their structural,morphological,optical and photocatalytic properties.X-ray diffraction(XRD) patterns,PL and Raman spectra results indicate that the undoped and Sm-doped ZnO nanostructures are crystallized in a hexagonal wurtzite structure.FESEM images show that the morphology of the sample changes from cubical to hexagonal nanostructures with increase in Sm3+doping concentration.The EDX spectra confirm the incorporation of Sm3+ion in ZnO.The influence of Sm3+doping on the structure,morphology,absorption,emission and photocatalytic activity of ZnO nanostructures were investigated systematically.The addition of Sm3+ion leads to a red shift in the optical energy band gap from 3.19 to 2.67 eV and hence,increases the visible light absorption ability.The presence of E2(H) and E1(LO) modes in microRaman spectra confirms the crystallinity and defects in the samples.The detailed photocatalytic experiments reveal that Sm-doped ZnO nanostructures show the maximum photodegradation efficiency for Methylene blue(MB) dye for x=0.04,i,e.,94.94%,under visible light irradiation.The photocatalytic efficiency improves by 6.98 times when ZnO is doped with rare earth metal ion(Sm3+) and is a potential candidate for practical applications.The investigation demonstrates that as-synthesized nano-sized photocatalysts act as an efficient photocatalyst for the degradation of MB dye.展开更多
Sm-doped Fe_(2)O_(3)catalysts,with a homogeneous distribution of Sm in Fe_(2)O_(3)nanoparticles,were synthesized using a citric acid-assisted sol-gel method.Kinetic studies show that the reaction rate for NO_(x)reduct...Sm-doped Fe_(2)O_(3)catalysts,with a homogeneous distribution of Sm in Fe_(2)O_(3)nanoparticles,were synthesized using a citric acid-assisted sol-gel method.Kinetic studies show that the reaction rate for NO_(x)reduction using the optimal catalyst(0.06 mol%doping of Sm in Fe_(2)O_(3))was nearly 11 times higher than that for pure Fe_(2)O_(3),when calculated based on specific surface area.Furthermore,the Fe_(0.94)Sm_(0.06)O_(x)catalyst maintains>83%NO_(x)conversion for 168 h at a high space velocity in the presence of SO_(2)and H_(2)O at 250℃.A substantial amount of surface-adsorbed oxygen was generated on the surface of Fe_(0.94)Sm_(0.06)O_(x),which promoted NO oxidation and the subsequent fast reaction between NO_(x)and NH_(3).The adsorption and activation of NH_(3)was also enhanced by Sm doping.In addition,Sm doping facilitated the decomposition of NH_(4)HSO_(4)on the surface of Fe_(0.94)Sm_(0.06)O_(x),resulting in its high activity and stability in the presence of SO_(2)+H_(2)O.展开更多
The Sm-doped Pb(Mg1/3Nb2/3)O3-PbTiO3(Sm-PMN-PT)single crystals were successfully grown and systematically investigated with the support of the National Natural Science Foundation of China.The research team is led by P...The Sm-doped Pb(Mg1/3Nb2/3)O3-PbTiO3(Sm-PMN-PT)single crystals were successfully grown and systematically investigated with the support of the National Natural Science Foundation of China.The research team is led by Prof.Li Fei(李飞)at the Electronic Materials Research Laboratory,School of Electronic and Information Engineering,Xi'an Jiaotong University,and with collaboration of The Pennsylvania State University,University of Wollongong,University of South Carolina,University of Arkansas,etc.This work was published in Science(2019,364:264—268).展开更多
The development of piezoelectric ceramics characterized by both large piezoelectric response and high-temperature stability is imperative for the advancement of practical electromechanical devices.However,existing hig...The development of piezoelectric ceramics characterized by both large piezoelectric response and high-temperature stability is imperative for the advancement of practical electromechanical devices.However,existing high-performance piezoelectric ceramics often encounter compromised temperature stability because ferroelectric phase transitions occur within low-temperature regions.In this work,we focused on Sm-doped Pb(Ni_(1/3)Nb_(2/3))O_(3)-PbZrO_(3)-PbTiO_(3)(PNN-PZT:Sm)ceramics with a tetragonal(T)-phase structure to achieve the desired combination of high piezoelectricity and high temperature stability.The results indicate that 2 mol%Sm-doped samples exhibit a large piezoelectric constant(d_(33))of 575 pC/N,an effective piezoelectric strain coefficient(d_(33)*)of 890 pm/V,and a high ferroelectric-to-paraelectric phase transition temperature(Tm)of 279℃.Remarkably,d_(33) experiences only a 2.6%variation over the temperature range of 30-250℃,while d_(33)*changes by 8%within the temperature range of 30-180℃.Microstructural and domain structure analyses suggest that Sm-doping effectively reduces the grain size,leading to a decreased domain size,thereby achieving excellent electromechanical properties.The superior temperature stability is attributed to the suppressive effect of Sm-doping on the R-T ferroelectric phase transition.These studies suggest that Sm-doping represents an effective strategy for achieving the collaborative optimization of piezoelectricity and temperature stability through grain and domain engineering techniques for perovskite ferroelectric materials.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11474339)the National Basic Research Program of China(Grant Nos.2010CB923000 and 2011CBA00100)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB07020100)
文摘In this article,the Sm-doping single crystals Ca1-xSmxFe2As2（x = 0 0.2） were prepared by the Ca As flux method,and followed by a rapid quenching treatment after the high temperature growth.The samples were characterized by structural,resistive,and magnetic measurements.The successful Sm-substitution was revealed by the reduction of the lattice parameter c,due to the smaller ionic radius of Sm3＋than Ca2＋.Superconductivity was observed in all samples with onset Tc varying from 27 K to 44 K upon Sm-doping.The coexistence of a collapsed phase transition and the superconducting transition was found for the lower Sm-doping samples.Zero resistivity and substantial superconducting volume fraction only happen in higher Sm-doping crystals with the nominal x 〉 0.10.The doping dependences of the c-axis length and onset Tc were summarized.The high-Tc observed in these quenched crystals may be attributed to simultaneous tuning of electron carriers doping and strain effect caused by lattice reduction of Sm-substitution.
基金financially supported by the National Natural Science Foundation of China(No.51878169)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110760)+1 种基金Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2017)。
文摘A heterojunction of Sm-doped g-C_(3)N_(4)/Ti_(3)C_(2) MXene(SCN/MX)was constructed via prepolymerization and solid mixture-calcination method.The modified g-C_(3)N_(4) presented a hollow porous seaweed-like shape which can increase its specific area and active sites.In SCN/MX composite,the optical properties,no matter optical absorption ability or separation performance of photo-induced electrons and holes,were enhanced.Among them,Sm-doping may play an important role on transferring the photogenerated electrons to suppress their recombination,and Ti_(3)C_(2) MXene would broaden light absorption and further improve the carrier migration efficiency.The SCN/MX presented higher photocatalytic degradation efficiency(>99%)of cipro floxacin under visible light irradiation.The quenching experiments and electron spin-resonance spectroscopy confirmed that the dominated active materials were superoxide radical and holes.The degradation mechanisms of ciprofloxacin(CIP)over the SCN/MX were attacking of the active materials on the piperazine ring and quinolone ring,and the final products were CO_(2),H_(2)O and F^(-).
文摘In the present work,we have synthesized samarium doped zinc oxide nanostructures(Zn1-xSmxO;x=0.00,0.02,0.04 and 0.06) via chemical precipitation method and studied their structural,morphological,optical and photocatalytic properties.X-ray diffraction(XRD) patterns,PL and Raman spectra results indicate that the undoped and Sm-doped ZnO nanostructures are crystallized in a hexagonal wurtzite structure.FESEM images show that the morphology of the sample changes from cubical to hexagonal nanostructures with increase in Sm3+doping concentration.The EDX spectra confirm the incorporation of Sm3+ion in ZnO.The influence of Sm3+doping on the structure,morphology,absorption,emission and photocatalytic activity of ZnO nanostructures were investigated systematically.The addition of Sm3+ion leads to a red shift in the optical energy band gap from 3.19 to 2.67 eV and hence,increases the visible light absorption ability.The presence of E2(H) and E1(LO) modes in microRaman spectra confirms the crystallinity and defects in the samples.The detailed photocatalytic experiments reveal that Sm-doped ZnO nanostructures show the maximum photodegradation efficiency for Methylene blue(MB) dye for x=0.04,i,e.,94.94%,under visible light irradiation.The photocatalytic efficiency improves by 6.98 times when ZnO is doped with rare earth metal ion(Sm3+) and is a potential candidate for practical applications.The investigation demonstrates that as-synthesized nano-sized photocatalysts act as an efficient photocatalyst for the degradation of MB dye.
文摘Sm-doped Fe_(2)O_(3)catalysts,with a homogeneous distribution of Sm in Fe_(2)O_(3)nanoparticles,were synthesized using a citric acid-assisted sol-gel method.Kinetic studies show that the reaction rate for NO_(x)reduction using the optimal catalyst(0.06 mol%doping of Sm in Fe_(2)O_(3))was nearly 11 times higher than that for pure Fe_(2)O_(3),when calculated based on specific surface area.Furthermore,the Fe_(0.94)Sm_(0.06)O_(x)catalyst maintains>83%NO_(x)conversion for 168 h at a high space velocity in the presence of SO_(2)and H_(2)O at 250℃.A substantial amount of surface-adsorbed oxygen was generated on the surface of Fe_(0.94)Sm_(0.06)O_(x),which promoted NO oxidation and the subsequent fast reaction between NO_(x)and NH_(3).The adsorption and activation of NH_(3)was also enhanced by Sm doping.In addition,Sm doping facilitated the decomposition of NH_(4)HSO_(4)on the surface of Fe_(0.94)Sm_(0.06)O_(x),resulting in its high activity and stability in the presence of SO_(2)+H_(2)O.
文摘The Sm-doped Pb(Mg1/3Nb2/3)O3-PbTiO3(Sm-PMN-PT)single crystals were successfully grown and systematically investigated with the support of the National Natural Science Foundation of China.The research team is led by Prof.Li Fei(李飞)at the Electronic Materials Research Laboratory,School of Electronic and Information Engineering,Xi'an Jiaotong University,and with collaboration of The Pennsylvania State University,University of Wollongong,University of South Carolina,University of Arkansas,etc.This work was published in Science(2019,364:264—268).
基金supported by the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110498)the Natural Science Foundation of China(No.51672100)+2 种基金the International Cooperation Project of Guangdong Province(No.2019A050510049)the Professorial and Doctoral Scientific Research Foundation of Huizhou University(No.2022JB030)the Innovative Research Team of Guangdong Province&Huizhou University(IRTHZU)。
文摘The development of piezoelectric ceramics characterized by both large piezoelectric response and high-temperature stability is imperative for the advancement of practical electromechanical devices.However,existing high-performance piezoelectric ceramics often encounter compromised temperature stability because ferroelectric phase transitions occur within low-temperature regions.In this work,we focused on Sm-doped Pb(Ni_(1/3)Nb_(2/3))O_(3)-PbZrO_(3)-PbTiO_(3)(PNN-PZT:Sm)ceramics with a tetragonal(T)-phase structure to achieve the desired combination of high piezoelectricity and high temperature stability.The results indicate that 2 mol%Sm-doped samples exhibit a large piezoelectric constant(d_(33))of 575 pC/N,an effective piezoelectric strain coefficient(d_(33)*)of 890 pm/V,and a high ferroelectric-to-paraelectric phase transition temperature(Tm)of 279℃.Remarkably,d_(33) experiences only a 2.6%variation over the temperature range of 30-250℃,while d_(33)*changes by 8%within the temperature range of 30-180℃.Microstructural and domain structure analyses suggest that Sm-doping effectively reduces the grain size,leading to a decreased domain size,thereby achieving excellent electromechanical properties.The superior temperature stability is attributed to the suppressive effect of Sm-doping on the R-T ferroelectric phase transition.These studies suggest that Sm-doping represents an effective strategy for achieving the collaborative optimization of piezoelectricity and temperature stability through grain and domain engineering techniques for perovskite ferroelectric materials.
