A series of transition metal ion-doped TiO_(2)composites were prepared by polyethyleneimine-assisted solvent-free selfassembly.Due to the similar electronegativity and ionic radius of Ti and Zr ions,the introduction o...A series of transition metal ion-doped TiO_(2)composites were prepared by polyethyleneimine-assisted solvent-free selfassembly.Due to the similar electronegativity and ionic radius of Ti and Zr ions,the introduction of Zr element to TiO_(2)can effectively improve its surface acidity and introduce more defect sites on the TiO_(2)framework.As-fabricated Zr-doped TiO_(2)nanocomposite exhibits the formation of Zr-Ti bond,strong surface acidity,connected mesoporous channels,and relatively high crystallinity.These remarkable properties contribute to its adsorption-oxidation-desulfurization capacity toward thiophene-type sulfides,which can remove 500×^(10-6)dibenzothiophene from the model fuel within 100 min at low reaction temperatures.The polymer-induced self-assembly method can reduce organic solvent usage,pollutant emissions,and energy consumption,which provides an efficient and practical way to prepare porous metal oxide-based catalysts in future.展开更多
A series of erbium ion-doped TiO2（Er^3＋-TiO2） films were prepared by a sol-gel dip/spin coating method, and the effect of the dosage of erbium ion（0-2.0 mol%）, the films coating layers（1-5 layers）, and calcinat...A series of erbium ion-doped TiO2（Er^3＋-TiO2） films were prepared by a sol-gel dip/spin coating method, and the effect of the dosage of erbium ion（0-2.0 mol%）, the films coating layers（1-5 layers）, and calcination temperature（400-700 ℃） on the film structure and photocatalytic activity were investigated in detail. The films were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM）, thermal analysis（TG-DTG） and UV-Vis diffusive reflectance spectra（DRS）. The results showed that the films were composed of anatase, and no other TiO2 phases（rutile and brookite）. With the increase of the erbium ion dosage, the crystal size decreased. Erbium ion doping could enhance the thermal stability of TiO2 and inhibit the increase of the crystallite size. Meanwhile doping of erbium ions gave rise to three typical absorption peaks within the range of visible light（400-700 nm）, locating at 490, 523, and 654 nm, attributed to the transition of 4 f electrons. The higher calcination temperature led to higher crystallinity and bigger crystal grains. The photocatalytic performance of the films was evaluated by degradation of methyl orange solution under simulated solar light. The highest quality film we prepared was with 4 layers, 1.0 mol% dosage of erbium ion, and the calcination temperature of 500 ℃. With this film,the degradation percentage of 7.8 mg/L methyl orange solution was up to 53.3% under simulated solar light after 6 h photoreaction.展开更多
Multicolor luminescent rare-earth ion-doped Y2O3 nanocrystals （NCs） were prepared by a solvethermal method. The as-synthesized NCs yielded nanosheets, nanowires （NWs） and nanorods （NRs） with the increase of alka...Multicolor luminescent rare-earth ion-doped Y2O3 nanocrystals （NCs） were prepared by a solvethermal method. The as-synthesized NCs yielded nanosheets, nanowires （NWs） and nanorods （NRs） with the increase of alkali （NaOH） in oleic acid system. Moreover, Y203 nanowires with controllable size have also been obtained. After sintering, the PL intensity of Y2O3：Ln3＋ nanocrystals increased with the changed morphology of the precursor, that is, Y（OH）3 nanocrystals. Both downconversion （red emission for Y2O3：Eu3＋ and green emission for Y2O3：Tb3＋） and upconversion （red emission for Y2O3：Yb/Er3＋） luminescence of the as-prepared nanocrystals have been demonstrated in this work. We also found that the PL intensity of Y2O3：Ln3＋ NCs dispersed in polar solvent was stronger than that in nonpolar solvent. Their up/downconversion fluorescence and controllable morphology might promise further fundamental research and biochemistry such as nanoscale optoelectronics, nanolasers, and ultrasensitive multicolor biolables.展开更多
Rational design of high-performance electrocatalysts for hydrogen evolution reaction(HER)is vital for future renewable energy systems.The incorporation of foreign metal ions into catalysts can be an effective approach...Rational design of high-performance electrocatalysts for hydrogen evolution reaction(HER)is vital for future renewable energy systems.The incorporation of foreign metal ions into catalysts can be an effective approach to optimize its performance.However,there is a lack of systematic theoretical studies to reveal the quantitative relationships at the electronic level.Here,we develop a multi-level screening methodology to search for highly stable and active dopants for CoP catalysts.The density functional theory(DFT)calculations and symbolic regression(SR)were performed to investigate the relationship between the adsorption free energy(ΔG_(H^(*)))and 10 electronic parameters.The mathematic formulas derived from SR indicate that the difference of work function(ΔΦ)between doped metal and the acceptor plays the most important role in regulatingΔG_(H^(*)),followed by the d-band center(d-BC)of doped system.The descriptor of HER can be expressed asΔG_(H^(*))=1.59×√|0.188ΔΦ+d BC+0.120|1/2-0.166 with a high determination coefficient(R^(2)=0.807).Consistent with the theoretical prediction,experimental results show that the Al-CoP delivers superior electrocatalytic HER activity with a low overpotential of75 m V to drive a current density of 10 mA cm^(-2),while the overpotentials for undoped CoP,Mo-CoP,and V-CoP are 206,134,and 83 m V,respectively.The current work proves that theΔΦis the most significant regulatory parameter ofΔG_(H^(*))for ion-doped electrocatalysts.This finding can drive the discovery of high-performance ion-doped electrocatalysts,which is crucial for electrocatalytic water splitting.展开更多
A Ce^（3＋）tion-doped α-Na YF_4 single crystal of high quality is grown successfully by an improved flux Bridgman method under the conditions of taking the chemical raw composition of Na F：KF：YF_3：CeF_3 in the mo...A Ce^（3＋）tion-doped α-Na YF_4 single crystal of high quality is grown successfully by an improved flux Bridgman method under the conditions of taking the chemical raw composition of Na F：KF：YF_3：CeF_3 in the molar ratio of30∶18∶48∶4, where the KF is shown to be an effective assistant flux. The x ray diffraction, absorption spectra,excitation spectra, and emission spectra of the Ce^（3＋）t-doped α-Na YF_4 single crystal are measured to investigate the phase and optical properties of the single crystals. The absorption spectrum of the Ce^（3＋）t：α-Na YF_4 shows a strong band that peaks at the wavelength of 300 nm. The emission spectrum of the Ce^（3＋）t：α-Na YF_4 emits an intense ultraviolet（UV） band at the wavelength of 332 nm under the excitation of 300 nm light. Two separated luminous bands of 330 and 350 nm, which correspond to the transitions 5d → 2F25∕2and 5d → F7∕2, can be obtained by Gauss fitting. The strong emission intensity at the UV band and the excellent optical transmission in the range of UV wavelengths indicate that Ce^（3＋）t：α-Na YF_4 single crystals can be considered as a promising material for UV lasers.展开更多
The ability to control the energy transfer in rare-earth ion-doped luminescent materials is very important for various related application areas such as color display, bio-labeling, and new light sources. Here, a phas...The ability to control the energy transfer in rare-earth ion-doped luminescent materials is very important for various related application areas such as color display, bio-labeling, and new light sources. Here, a phase-shaped femtosecond laser field is first proposed to control the transfer of multiphoton excited energy from Tm^(3+) to Yb^(3+) ions in co-doped glass ceramics. Tm^(3+) ions are first sensitized by femtosecond laser-induced multiphoton absorption, and then a highly efficient energy transfer occurs between the highly excited state Tm^(3+) sensitizers and the ground-state Yb^(3+) activators. The laser peak intensity and polarization dependences of the laser-induced luminescence intensities are shown to serve as proof of the multiphoton excited energy transfer pathway.The efficiency of the multiphoton excited energy transfer can be efficiently enhanced or completely suppressed by optimizing the spectral phase of the femtosecond laser with a feedback control strategy based on a genetic algorithm. A(1+2) resonance-mediated three-photon excitation model is presented to explain the experimental observations. This study provides a new way to induce and control the energy transfer in rare-earth ion-doped luminescent materials, and should have a positive contribution to the development of related applications.展开更多
The reversible transfer of unknown quantum states between light and matter is essential for constructing large-scale quantum networks. Over the last decade, various physical systems have been proposed to realize such ...The reversible transfer of unknown quantum states between light and matter is essential for constructing large-scale quantum networks. Over the last decade, various physical systems have been proposed to realize such quantum memory for light. The solid-state quantum memory based on rare-earth-ion-doped solids has the advantages of a reduced setup complexity and high robustness for scalable application. We describe the methods used to spectrally prepare the quantum memory and release the photonic excitation on-demand. We will review the state of the art experiments and discuss the perspective applications of this particular system in both quantum information science and fundamental tests of quantum physics.展开更多
基金supported by Hubei Provincial Natural Science Foundation and Huangshi of China(2022CFD039)the National Natural Science Foundation of China(22008058)Program for Innovative Teams of Outstanding Young and Middle-aged Researchers in the Higher Education Institutions of Hubei Province(T2021010)。
文摘A series of transition metal ion-doped TiO_(2)composites were prepared by polyethyleneimine-assisted solvent-free selfassembly.Due to the similar electronegativity and ionic radius of Ti and Zr ions,the introduction of Zr element to TiO_(2)can effectively improve its surface acidity and introduce more defect sites on the TiO_(2)framework.As-fabricated Zr-doped TiO_(2)nanocomposite exhibits the formation of Zr-Ti bond,strong surface acidity,connected mesoporous channels,and relatively high crystallinity.These remarkable properties contribute to its adsorption-oxidation-desulfurization capacity toward thiophene-type sulfides,which can remove 500×^(10-6)dibenzothiophene from the model fuel within 100 min at low reaction temperatures.The polymer-induced self-assembly method can reduce organic solvent usage,pollutant emissions,and energy consumption,which provides an efficient and practical way to prepare porous metal oxide-based catalysts in future.
文摘A series of erbium ion-doped TiO2（Er^3＋-TiO2） films were prepared by a sol-gel dip/spin coating method, and the effect of the dosage of erbium ion（0-2.0 mol%）, the films coating layers（1-5 layers）, and calcination temperature（400-700 ℃） on the film structure and photocatalytic activity were investigated in detail. The films were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM）, thermal analysis（TG-DTG） and UV-Vis diffusive reflectance spectra（DRS）. The results showed that the films were composed of anatase, and no other TiO2 phases（rutile and brookite）. With the increase of the erbium ion dosage, the crystal size decreased. Erbium ion doping could enhance the thermal stability of TiO2 and inhibit the increase of the crystallite size. Meanwhile doping of erbium ions gave rise to three typical absorption peaks within the range of visible light（400-700 nm）, locating at 490, 523, and 654 nm, attributed to the transition of 4 f electrons. The higher calcination temperature led to higher crystallinity and bigger crystal grains. The photocatalytic performance of the films was evaluated by degradation of methyl orange solution under simulated solar light. The highest quality film we prepared was with 4 layers, 1.0 mol% dosage of erbium ion, and the calcination temperature of 500 ℃. With this film,the degradation percentage of 7.8 mg/L methyl orange solution was up to 53.3% under simulated solar light after 6 h photoreaction.
文摘Multicolor luminescent rare-earth ion-doped Y2O3 nanocrystals （NCs） were prepared by a solvethermal method. The as-synthesized NCs yielded nanosheets, nanowires （NWs） and nanorods （NRs） with the increase of alkali （NaOH） in oleic acid system. Moreover, Y203 nanowires with controllable size have also been obtained. After sintering, the PL intensity of Y2O3：Ln3＋ nanocrystals increased with the changed morphology of the precursor, that is, Y（OH）3 nanocrystals. Both downconversion （red emission for Y2O3：Eu3＋ and green emission for Y2O3：Tb3＋） and upconversion （red emission for Y2O3：Yb/Er3＋） luminescence of the as-prepared nanocrystals have been demonstrated in this work. We also found that the PL intensity of Y2O3：Ln3＋ NCs dispersed in polar solvent was stronger than that in nonpolar solvent. Their up/downconversion fluorescence and controllable morphology might promise further fundamental research and biochemistry such as nanoscale optoelectronics, nanolasers, and ultrasensitive multicolor biolables.
基金Financial support from the National Natural Science Foundation of China(21676216)the Special project of Shaanxi Provincial Education Department(20JC034)+1 种基金GHfund B(202202022563)Hefei Advanced Computing Center。
文摘Rational design of high-performance electrocatalysts for hydrogen evolution reaction(HER)is vital for future renewable energy systems.The incorporation of foreign metal ions into catalysts can be an effective approach to optimize its performance.However,there is a lack of systematic theoretical studies to reveal the quantitative relationships at the electronic level.Here,we develop a multi-level screening methodology to search for highly stable and active dopants for CoP catalysts.The density functional theory(DFT)calculations and symbolic regression(SR)were performed to investigate the relationship between the adsorption free energy(ΔG_(H^(*)))and 10 electronic parameters.The mathematic formulas derived from SR indicate that the difference of work function(ΔΦ)between doped metal and the acceptor plays the most important role in regulatingΔG_(H^(*)),followed by the d-band center(d-BC)of doped system.The descriptor of HER can be expressed asΔG_(H^(*))=1.59×√|0.188ΔΦ+d BC+0.120|1/2-0.166 with a high determination coefficient(R^(2)=0.807).Consistent with the theoretical prediction,experimental results show that the Al-CoP delivers superior electrocatalytic HER activity with a low overpotential of75 m V to drive a current density of 10 mA cm^(-2),while the overpotentials for undoped CoP,Mo-CoP,and V-CoP are 206,134,and 83 m V,respectively.The current work proves that theΔΦis the most significant regulatory parameter ofΔG_(H^(*))for ion-doped electrocatalysts.This finding can drive the discovery of high-performance ion-doped electrocatalysts,which is crucial for electrocatalytic water splitting.
基金supported by the National Natural Science Foundation of China(Nos.51472125 and51272109)the K.C.Wong Magna Fund of Ningbo University
文摘A Ce^（3＋）tion-doped α-Na YF_4 single crystal of high quality is grown successfully by an improved flux Bridgman method under the conditions of taking the chemical raw composition of Na F：KF：YF_3：CeF_3 in the molar ratio of30∶18∶48∶4, where the KF is shown to be an effective assistant flux. The x ray diffraction, absorption spectra,excitation spectra, and emission spectra of the Ce^（3＋）t-doped α-Na YF_4 single crystal are measured to investigate the phase and optical properties of the single crystals. The absorption spectrum of the Ce^（3＋）t：α-Na YF_4 shows a strong band that peaks at the wavelength of 300 nm. The emission spectrum of the Ce^（3＋）t：α-Na YF_4 emits an intense ultraviolet（UV） band at the wavelength of 332 nm under the excitation of 300 nm light. Two separated luminous bands of 330 and 350 nm, which correspond to the transitions 5d → 2F25∕2and 5d → F7∕2, can be obtained by Gauss fitting. The strong emission intensity at the UV band and the excellent optical transmission in the range of UV wavelengths indicate that Ce^（3＋）t：α-Na YF_4 single crystals can be considered as a promising material for UV lasers.
基金National Natural Science Foundation of China(NSFC)(11727810,11774094,61720106009,91850202)Shanghai Minhang Science and Technology Commission(16520721200,17ZR146900)
文摘The ability to control the energy transfer in rare-earth ion-doped luminescent materials is very important for various related application areas such as color display, bio-labeling, and new light sources. Here, a phase-shaped femtosecond laser field is first proposed to control the transfer of multiphoton excited energy from Tm^(3+) to Yb^(3+) ions in co-doped glass ceramics. Tm^(3+) ions are first sensitized by femtosecond laser-induced multiphoton absorption, and then a highly efficient energy transfer occurs between the highly excited state Tm^(3+) sensitizers and the ground-state Yb^(3+) activators. The laser peak intensity and polarization dependences of the laser-induced luminescence intensities are shown to serve as proof of the multiphoton excited energy transfer pathway.The efficiency of the multiphoton excited energy transfer can be efficiently enhanced or completely suppressed by optimizing the spectral phase of the femtosecond laser with a feedback control strategy based on a genetic algorithm. A(1+2) resonance-mediated three-photon excitation model is presented to explain the experimental observations. This study provides a new way to induce and control the energy transfer in rare-earth ion-doped luminescent materials, and should have a positive contribution to the development of related applications.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304100)the National Natural Science Foundation of China(Grant Nos.61327901,11774331,11774335,11504362,11325419,and 11654002)+1 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDY-SSW-SLH003)the Fundamental Research Funds for the Central Universities,China(Grant Nos.WK2470000023 and WK2470000026)
文摘The reversible transfer of unknown quantum states between light and matter is essential for constructing large-scale quantum networks. Over the last decade, various physical systems have been proposed to realize such quantum memory for light. The solid-state quantum memory based on rare-earth-ion-doped solids has the advantages of a reduced setup complexity and high robustness for scalable application. We describe the methods used to spectrally prepare the quantum memory and release the photonic excitation on-demand. We will review the state of the art experiments and discuss the perspective applications of this particular system in both quantum information science and fundamental tests of quantum physics.
