Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-depositi...Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_(1-x)Mn_(x)O_(3),prolonging the lifespan in acidic conditions by 14 times.The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH^(-).The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO_(2),which ensures that the long-term stability of LaCo_(1-x)Mn_(x)O_(3)is 70 h instead of 5 h for LaCoO_(3).Mn doping enhances the deprotonation of^(*)OOH→O_(2)in acidic environments.Notably,the over-potential of optimized LaCo_(1-x)Mn_(x)O_(3)is 345 mV at 10 mA cm^(-2)for acidic OER.This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.展开更多
Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of phot...Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of photoelectric devices.However,pristine Mn^(2+):CsPbCl_(3)NCs commonly suffer from low photoluminescence quantum yield(PL QY) and stability issues.Herein,we introduced europium ions(Eu^(3+))into Mn^(2+):CsPbCl_(3)NCs via the thermal injection synthesis method to obtain high performance Eu^(3+)and Mn^(2+)codoped CsPbCl_(3)(Eu^(3+)/Mn^(2+):CsPbCl_(3)) NCs.The maximum PL QY of the resulting Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs reaches up to 90.92%.It is found that the doping of Eu^(3+)ions significantly reduces the non-radiative recombination caused by high defect states,and improves the energy transfer efficiency from exciton to Mn^(2+),thereby boosting the PL performance.Moreover,doping Eu^(3+)ions notably improves the UV-light and water stability of Mn^(2+):CsPbCl_(3)NCs.We further demonstrate the application versatility of Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs in white light emitting diodes(WLEDs) and optical anticounterfeiting applications.This work provides a valuable perspective for the attainment of high performance Mn^(2+):CsPbCl_(3)NCs and lays a foundation for the codoping of other lanthanide ions to adjust the luminescence properties of Mn^(2+):CsPbCl_(3)NCs.展开更多
The Mn doping effects on the gate-tunable transport properties of topological Dirac semimetal Cd3As2 films have been investigated.Mn-doped Cd3As2 films are directly grown on GaAs(111)B substrates by molecular-beam epi...The Mn doping effects on the gate-tunable transport properties of topological Dirac semimetal Cd3As2 films have been investigated.Mn-doped Cd3As2 films are directly grown on GaAs(111)B substrates by molecular-beam epitaxy,during which the single crystal phase can be obtained with Mn concentration less than 2%.Shubnikov-de Haas oscillation and quantum Hall effect are observed at low temperatures,and electrons are found to be the dominant carrier in the whole temperature range.Higher Mn content results in smaller lattice constant,lower electron mobility and larger effective band gap,while the carrier density seems to be unaffected by Mn-doping.Gating experiments show that Shubnikov-de Haas oscillation and quantum Hall effect are slightly modulated by electric field,which can be explained by the variation of electron density.Our results provide useful information for understanding the magnetic element doping effects on the transport properties of Cd3As2 films.展开更多
The first-principles calculations are performed to investigate the structural,mechanical property,hardness,and electronic structure of WCoB with 0,8.33,16.67,25,and 33.33 at.%Mn doping content and W_2 CoB_2 with 0,10,...The first-principles calculations are performed to investigate the structural,mechanical property,hardness,and electronic structure of WCoB with 0,8.33,16.67,25,and 33.33 at.%Mn doping content and W_2 CoB_2 with 0,10,and 20 at.%Mn doping content.The cohesive energy and formation energy indicate that all the structures can retain good structural stability.According to the calculated elastic constants,Mn is responsible for the increase of ductility and Poisson's ratio and the decrease of Young's modulus,shear modulus,and bulk modulus.By using the population analysis and mechanical properties,the hardness is characterized through using the five hardness models and is found to decrease with the Mn doping content increasing.The calculated electronic structure indicates that the formation of a B–Mn covalent bond and a W–Mn metallic bond contribute to the decreasing of the mechanical properties.展开更多
To investigate the enhancing effect of Mn on the performance of simultaneous catalytic oxidation of AsH_(3)and PH_(3)by CuO-Al_(2)O_(3)in a reducing atmosphere under micro-oxygen conditions,Cu-Mn modifiedγ-Al_(2)O_(3...To investigate the enhancing effect of Mn on the performance of simultaneous catalytic oxidation of AsH_(3)and PH_(3)by CuO-Al_(2)O_(3)in a reducing atmosphere under micro-oxygen conditions,Cu-Mn modifiedγ-Al_(2)O_(3)catalysts were prepared.The characteristics of the catalysts showed that Mn reduced the crystallinity of the active CuO component,increased the number of oxygen vacancies and acidic sites on the catalyst surface,enhanced the mobility of surface oxygen,and the interaction between copper and manganese promoted the redox cycling ability of the catalysts and improved their oxidation performance,which increased the conversion frequency(TOF)by 2.54×10^(-2)to 3.07×10^(-2)sec^(-1).On the other hand,the introduction of Mn reduced the production of phosphate and As_(2)O_(3)on the catalyst surface by30.96%and 44.9%,which reduced the coverage and inerting of the active sites by phosphate and As_(2)O_(3),resulting in an 8 hr(6 hr)improvement in the stability of PH_(3)(AsH_(3))removal.展开更多
Nd1.85Ce0.15Cu1-xMnxO4 samples with doping level up to 20% have been synthesized by solid-state reaction method. The influence of Mn on their normal-state transport, crystal structure, superconductivity and magnetic p...Nd1.85Ce0.15Cu1-xMnxO4 samples with doping level up to 20% have been synthesized by solid-state reaction method. The influence of Mn on their normal-state transport, crystal structure, superconductivity and magnetic properties has been investigated. For the samples with x〉0.03, magnetization under zero-field cooling indicates that the magnetic state changes from ferromagnetic to paramagnetic at T≈100 K, which can be explained with the interaction between Mn4＋and Mn3＋. The electrical resistivity p of samples increases with Mn doping. For the samples with doping level lower than 0.20, p initially increases with the decrease of temperature, i.e., dp/dt〈0, and then shows superconductivity transition at ≈20 K. The results suggest the coexistence of superconductivity and ferromagnetic ordering in Mn doped Nd1.85Ce0.15CuO4.展开更多
Antiperovskite compounds Mn3Ag1-xCoxN （x =0.2, 0.5 and 0.8） are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction o...Antiperovskite compounds Mn3Ag1-xCoxN （x =0.2, 0.5 and 0.8） are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction of Co. However, with the increase of the content of Co, the spin reorientation gradually disappears and the antiferromagnetic transition changes to the ferromagnetic transition at the elevated temperature when x = 0.8. In addition, all of the magnetic phase transitions at the elevated temperature are always accompanied by the abnormal thermal expansion behaviors and an entropy change. Moreover, when x = 0.8, the coefficient of linear expansion is -1.89 × 10^-6 K^-1 （290-310K, △T =20 K）, which is generally considered as the low thermal expansion.展开更多
CeO2-ZrO2-MnOx mixed oxide series were prepared by sol-gel method. CO pulse and CO-O2 cycle measurements were carried out to examine the oxygen storage complete capacity （OSCC） and dynamic oxygen storage capacity （...CeO2-ZrO2-MnOx mixed oxide series were prepared by sol-gel method. CO pulse and CO-O2 cycle measurements were carried out to examine the oxygen storage complete capacity （OSCC） and dynamic oxygen storage capacity （OSC） of the samples. The doping method brought about strong interactions between manganese oxide and ceria, both in the bulk and on the surface. Only a small part of Mn cations are incorporated into the ceria lattice to form solid solutions and the remaining are left on the surface as finely dispersed Mn3O4. The OSC behaviors of the materials are influenced by the doping amount of Mn and the solubility of Mn in the CeO2 lattice. The OSC is more easily affected by available contents of oxygen storage components when the measurement frequency is low. Comparatively, the concentration of lattice defects, which affects the mobility of bulk oxygen, is the determining factor under high frequency.展开更多
In the present work, ribbon and 2-mm rod samples of Mg-Zn-Ca-Mn alloys were prepared by meltspinning and copper mold injection methods, respectively. Effects of Mn doping on glass-forming ability and corrosion perform...In the present work, ribbon and 2-mm rod samples of Mg-Zn-Ca-Mn alloys were prepared by meltspinning and copper mold injection methods, respectively. Effects of Mn doping on glass-forming ability and corrosion performance in simulated body fluid of Mg65Zn30Ca5 alloy were studied through X-ray diffraction, scanning electron microscopy, differential scanning calorimeter, and electrochemical and immersion tests. Results show that with the Mn addition increasing, all the ribbon samples are completely in amorphous state. However, the microstructure of 2-mm rod samples transfers from fully amorphous for the Mn-free alloy to almost polycrystalline state with precipitated Mg, Mn, and MgZn phases. Glass-forming ability of Mg65Zn30Ca5 alloy is decreased by Mn addition. Results of electrochemical and immersion tests demon- strate that the Mn-doped samples exhibit more negative corrosion potential and larger corrosion current density, suggesting that the corrosion resistance decreases with doping amount of Mn element increasing.展开更多
LiFePO_(4),as a prevailing cathode material for lithium-ion batteries(LIBs),still encounters issues such as intrinsic poor electronic conductivity,inferior Li-ion diffusion kinetic,and two-phase transformation mechani...LiFePO_(4),as a prevailing cathode material for lithium-ion batteries(LIBs),still encounters issues such as intrinsic poor electronic conductivity,inferior Li-ion diffusion kinetic,and two-phase transformation mechanism involving substantial structural rearrangements,resulting in unsatisfactory rate performance.Carbon coating,cation doping,and morphological control have been widely employed to reconcile these issues.Inspired by these,we propose a synthetic route with metal–organic frameworks(MOFs)as self-sacrificial templates to simultaneously realize shape modulation,Mn doping,and N-doped carbon coating for enhanced electrochemical performances.The as-synthesized Li MnxFe1–xPO4/C(x=0,0.25,and0.5)deliver tunable electrochemical behaviors induced by the MOF templates,among which LiMn_(0.25)Fe_(0.75)PO_(4)/C outperforms its counterparts in cyclability(164.7 mA h g^(-1)after 200 cycles at 0.5 C)and rate capability(116.3 mA h g^(-1)at 10 C).Meanwhile,the ex-situ XRD reveals a dominant single-phase solid solution mechanism of LiMn_(0.25)Fe_(0.75)PO_(4)/C during delithiation,contrary to the pristine LiFePO_(4),without major structural reconstruction,which helps to explain the superior rate performance.Furthermore,the density functional theory(DFT)calculations verify the effects of Mn doping and embody the superiority of LiMn_(0.25)Fe_(0.75)PO_(4)/C as a LIB cathode,which well supports the experimental observations.This work provides insightful guidance for the design of tunable MOF-derived mixed transitionmetal systems for advanced LIBs.展开更多
NiCr2O4（NCO）spinel composites with different Mn/Ni atomic ratios（Mn/Ni=0.05,0.10,0.15,and 0.20）were synthesized via solid state reaction method.Phase compositions and microstructure of samples were characterized b...NiCr2O4（NCO）spinel composites with different Mn/Ni atomic ratios（Mn/Ni=0.05,0.10,0.15,and 0.20）were synthesized via solid state reaction method.Phase compositions and microstructure of samples were characterized by X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）.The TG-DSC curves showed that the appropriate baking temperature for Mn-doped NCO spinel preparation was approximately 1 320℃.X-ray diffraction patterns exhibited the formation of NCO spinel with Fd-3m space group.Valence state of the Mn ions was determined from 2p and 3s X-ray photoelectron spectra.Manganese ions were mostly in divalent and trivalent states,and the ratio of Mn^2＋/Mn^3＋was 0.78-0.98.Fourier transform infrared spectroscopy（FTIR）was used to analyze the spectral emissivity of Mn doped NCO spinel.It was revealed that the infrared emissivity of Mn-doped NCO spinel in 1.8-5μm could be significantly enhanced with increasing content of Mn^2＋,reaching as high as 0.9398.Mn-doped NCO spinel showed excellent radiation performance and good prospect in high emissivity applications in the temperature range of 800-1 200℃.展开更多
The effects of Mn addition(0.005,0.01,0.03,0.05,and 0.07 wt.%)on microstructure,shear mechanical behavior,and interfacial thermal stabilities of SAC305 joints were investigated under isothermal aging temperatures of 1...The effects of Mn addition(0.005,0.01,0.03,0.05,and 0.07 wt.%)on microstructure,shear mechanical behavior,and interfacial thermal stabilities of SAC305 joints were investigated under isothermal aging temperatures of 170 C with different aging time(0,250,500,and 750 h).It is found that Mn addition can increase fracture energy of joints without decreasing the shear strength.And the microstructures have transformed from the eutectic net-like structure in SAC305 solder joints into the structures based onβ-Sn matrix with intermetallic compounds(IMCs)distributed.By doping 0.07 wt.%Mn,the Cu_(6)Sn_(5) growth along the SAC305/Cu interface during thermal aging can be inhibited to some extent.During isothermal aging at 170°C,the maximum shear force of solder joint decreases continuously with aging time increasing,while the fracture energy rises first and then decreases,reaching the maximum at 500 h compared by that with the microstructure homogenization.Cu_(3)Sn growth between Cu_(3)Sn_(5)/Cu interface has been retarded most at the aging time of 250 h with 0.07 wt.%Mn-doped joints.With the aging time prolonging,the inhibition effect of Mn on CusSn IMC layer becomes worse.The strengthening effect of Mn can be explained by precipitation strengthening,and its mechanical behavior can be predicted by particle strengthening model proposed by Orowan.展开更多
Lead-free Bi_(_(0.5))Na_(_(0.5))TiO_(3)(BNT)piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures.But the improvement of piezoelectric coefficient(d 33)is usually accompanied ...Lead-free Bi_(_(0.5))Na_(_(0.5))TiO_(3)(BNT)piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures.But the improvement of piezoelectric coefficient(d 33)is usually accompanied by a huge sacrifice of depolarization temperature(T d).In this work,a well-balanced performance of d 33 and T d is achieved in MnO_(2)-doped 0.79(Bi_(_(0.5))Na_(_(0.5))TiO_(3))-0.14(Bi_(0.5)K_(0.5)TiO_(3))-0.07BaTiO_(3)ternary ceramics.The in-corporation of 0.25 mol%MnO_(2)enhances the d 33 by more than 40%,while T d remains almost unchanged(i.e.,d 33=181 pC/N,T d=184℃).X-ray diffraction(XRD)shows that an appropriate fraction of the small axis-ratio ferroelectric phase(pseudo-cubic,P c)coexists with the long-range ferroelectric phase(tetrag-onal,T)under this MnO_(2)doping.Piezoelectric force microscopy(PFM)has revealed a special domain configuration,namely large striped and layered macro domains embedded with small nanodomains.This study provides a distinctive avenue to design BNT-based piezoelectric ceramics with high piezoelectric performance and temperature stability.展开更多
The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of M...The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.展开更多
Transition metal sulfides(TMSs)have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding conductivity.Herein,we report a self-support...Transition metal sulfides(TMSs)have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding conductivity.Herein,we report a self-supported hierarchical Mn doped Co_(9)S_(8)@Co(OH)_(2) nanosheet arrays on nickel foam(NF)substrate by a one-step metal–organic-framework(MOF)engaged approach and a subsequent sulfurization process.Experimental results reveal that the introduction of manganese endows improved electric conductivity,enlarged electrochemical specific surface area,adjusted electronic structure of Co_(9)S_(8)@Co(OH)_(2) and enhanced interfacial activities as well as facilitated reaction kinetics of electrodes.The optimal Mn doped Co_(9)S_(8)@Co(OH)_(2) electrode exhibits an ultrahigh specific capacitance of 3745 F g^(-1) at 1 A g^(-1)(5.618 F cm^(-2) at 1.5 mA cm^(-2))and sustains 1710 F g^(-1) at 30 A g^(-1)(2.565 F cm^(-2) at 45 mA cm^(-2)),surpassing most reported values on TMSs.Moreover,a battery-type asymmetric supercapacitor(ASC)device is constructed,which delivers high energy density of 50.2 Wh kg^(-1) at power density of 800 W kg^(-1),and outstanding long-term cycling stability(94%capacitance retention after 8000 cycles).The encouraging results might offer an effective strategy to optimize the TMSs for energy-storage devices.展开更多
Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11...Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11～15 nm.The incorporation of Mn ions in CeO2 resulted in a lattice volume reduction.Mn ions showed a mixed valence state of ＋2,＋3 and ＋4 in CeO2 lattice.An obvious red-shift of the absorption threshold edge was observed from the UV-visible spectrum.Compared with the bulk CeO2,Ce1-xMnxO2-δ nanocrystals exhibited a lower releasing oxygen temperature as indicated by TPR technique.展开更多
CuIn1-xMnxTe2 samples have been synthesized by a melt-annealing method. The x-ray powder diffraction（XRD）analysis shows that the CuIn1-xMnxTe2 samples crystallize in the chalcopyrite phase. Mn doping can effectively...CuIn1-xMnxTe2 samples have been synthesized by a melt-annealing method. The x-ray powder diffraction（XRD）analysis shows that the CuIn1-xMnxTe2 samples crystallize in the chalcopyrite phase. Mn doping can effectively optimize the electrical properties and accordingly improve the power factor. The room temperature electrical conductivity of doped CuInTe2 increases by several orders of magnitude due to substituting In with Mn. In addition, a large reduction in thermal conductivity is achieved through the enhanced phonon scattering via Mn-related point defects and precipitates. Therefore,an enhanced average ZT value up to 0.34 is achieved for sample CuIn0.925Mn0.075Te2, which is 41% higher than that of the pristine CuInTe2.展开更多
As a low-bandgap ferroelectric material, BiFeO3 has gained wide attention for the potential photovoltaic applications,since its photovoltaic effect in visible light range was reported in 2009. In the present work, Bi...As a low-bandgap ferroelectric material, BiFeO3 has gained wide attention for the potential photovoltaic applications,since its photovoltaic effect in visible light range was reported in 2009. In the present work, Bi（Fe, Mn）O3thin films are fabricated by pulsed laser deposition method, and the effects of Mn doping on the microstructure, optical, leakage,ferroelectric and photovoltaic characteristics of Bi（Fe, Mn）O3 thin films are systematically investigated. The x-ray diffraction data indicate that Bi（Fe, Mn）O3 thin films each have a rhombohedrally distorted perovskite structure. From the light absorption results, it follows that the band gap of Bi（Fe, Mn）O3 thin films can be tuned by doping different amounts of Mn content. More importantly, photovoltaic measurement demonstrates that the short-circuit photocurrent density and the open-circuit voltage can both be remarkably improved through doping an appropriate amount of Mn content, leading to the fascinating fact that the maximum power output of ITO/BiFe（0.7）Mn（0.3）O3/Nb-STO capacitor is about 175 times higher than that of ITO/BiFeO3/Nb-STO capacitor. The improvement of photovoltaic response in Bi（Fe, Mn）O3 thin film can be reasonably explained as being due to absorbing more visible light through bandgap engineering and maintaining the ferroelectric property at the same time.展开更多
Large-scale flower-shaped Mn doped ZnO nanostructures have been grown on silicon substrates by simple thermal evaporation at atmospheric pressure.The flower-shaped nanostructure makes up of many nanorods,which are roo...Large-scale flower-shaped Mn doped ZnO nanostructures have been grown on silicon substrates by simple thermal evaporation at atmospheric pressure.The flower-shaped nanostructure makes up of many nanorods,which are rooted in one center.Analysis of X-ray diffraction,high-resolution transmission electron microscopy and Raman spectra results reveal that the products are of single phase with wurtzite structure.Elemental mapping results show that no impurity clusters exist in the doped materials.The photoluminescence spectra demonstrate that many oxygen vacancies exist in the doped materials,and the crystal quality is improved and the content of oxygen vacancies is decreased by annealing treatment.The flower-shaped Mn doped ZnO nanostructures exhibit ferromagnetic ordering above room temperature,and its magnetization is decreased by the annealing treatment,which indicates that the magnetic behavior of the doped materials may be related to the interaction between Mn doping and the oxygen vacancies.展开更多
Zn1-xMnxO bulks have been prepared by the solid state reaction method. Zn vapor treatment has been carried out to adjust the carrier concentration. For the Zn treated Zn1-xMnxO bulks, analysis of the temperature depen...Zn1-xMnxO bulks have been prepared by the solid state reaction method. Zn vapor treatment has been carried out to adjust the carrier concentration. For the Zn treated Zn1-xMnxO bulks, analysis of the temperature dependence of resistance and the field dependence of magnetoresistance demonstrates that the bound magnetic polarons （BMPs） play an important role in the electrical transport behavior. The hopping of BMPs dominates the electrical conduction behavior when temperature is below 170 K. At low temperature, paramagnetic Zn1-xMnxO bulks show a large magnetoresistance effect, which indicates that the large magnetoresistance effect in transition-metal doped ZnO dilute magnetic semiconductors is independent of their magnetic states.展开更多
基金financially supported by the Shandong Provincial Natural Science Foundation(ZR2023LFG005)the National Natural Science Foundation of China(Nos.22479161,52274308 and U22B20144)the Fundamental Research Funds for the Central Universities(No.24CX03012A)。
文摘Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_(1-x)Mn_(x)O_(3),prolonging the lifespan in acidic conditions by 14 times.The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH^(-).The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO_(2),which ensures that the long-term stability of LaCo_(1-x)Mn_(x)O_(3)is 70 h instead of 5 h for LaCoO_(3).Mn doping enhances the deprotonation of^(*)OOH→O_(2)in acidic environments.Notably,the over-potential of optimized LaCo_(1-x)Mn_(x)O_(3)is 345 mV at 10 mA cm^(-2)for acidic OER.This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.
基金Project supported by the National Natural Science Foundation of China (12174075)the Scientific and Technological Bases and Talents of Guangxi (Guike AD21220016)+1 种基金Guangxi Science and Technology Major Project(AA23073018)the special fund for Guangxi Bagui Scholars。
文摘Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of photoelectric devices.However,pristine Mn^(2+):CsPbCl_(3)NCs commonly suffer from low photoluminescence quantum yield(PL QY) and stability issues.Herein,we introduced europium ions(Eu^(3+))into Mn^(2+):CsPbCl_(3)NCs via the thermal injection synthesis method to obtain high performance Eu^(3+)and Mn^(2+)codoped CsPbCl_(3)(Eu^(3+)/Mn^(2+):CsPbCl_(3)) NCs.The maximum PL QY of the resulting Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs reaches up to 90.92%.It is found that the doping of Eu^(3+)ions significantly reduces the non-radiative recombination caused by high defect states,and improves the energy transfer efficiency from exciton to Mn^(2+),thereby boosting the PL performance.Moreover,doping Eu^(3+)ions notably improves the UV-light and water stability of Mn^(2+):CsPbCl_(3)NCs.We further demonstrate the application versatility of Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs in white light emitting diodes(WLEDs) and optical anticounterfeiting applications.This work provides a valuable perspective for the attainment of high performance Mn^(2+):CsPbCl_(3)NCs and lays a foundation for the codoping of other lanthanide ions to adjust the luminescence properties of Mn^(2+):CsPbCl_(3)NCs.
基金supported by NSFC(Grants Nos.U1632264 and 11704374)the the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB44000000 and QYZDY-SSW-JSC015)。
文摘The Mn doping effects on the gate-tunable transport properties of topological Dirac semimetal Cd3As2 films have been investigated.Mn-doped Cd3As2 films are directly grown on GaAs(111)B substrates by molecular-beam epitaxy,during which the single crystal phase can be obtained with Mn concentration less than 2%.Shubnikov-de Haas oscillation and quantum Hall effect are observed at low temperatures,and electrons are found to be the dominant carrier in the whole temperature range.Higher Mn content results in smaller lattice constant,lower electron mobility and larger effective band gap,while the carrier density seems to be unaffected by Mn-doping.Gating experiments show that Shubnikov-de Haas oscillation and quantum Hall effect are slightly modulated by electric field,which can be explained by the variation of electron density.Our results provide useful information for understanding the magnetic element doping effects on the transport properties of Cd3As2 films.
基金Project supported by the National Key Research and Development Program,China(Grant No.2016YFB0700503)the National High Technology Research and Development Program of China(Grant No.2015AA034201)+2 种基金the Beijing Science and Technology Plan,China(Grant No.D161100002416001)the National Natural Science Foundation of China(Grant No.51172018)the Kennametal Inc.,China
文摘The first-principles calculations are performed to investigate the structural,mechanical property,hardness,and electronic structure of WCoB with 0,8.33,16.67,25,and 33.33 at.%Mn doping content and W_2 CoB_2 with 0,10,and 20 at.%Mn doping content.The cohesive energy and formation energy indicate that all the structures can retain good structural stability.According to the calculated elastic constants,Mn is responsible for the increase of ductility and Poisson's ratio and the decrease of Young's modulus,shear modulus,and bulk modulus.By using the population analysis and mechanical properties,the hardness is characterized through using the five hardness models and is found to decrease with the Mn doping content increasing.The calculated electronic structure indicates that the formation of a B–Mn covalent bond and a W–Mn metallic bond contribute to the decreasing of the mechanical properties.
基金supported by the National Natural Science Foundation of China (Nos.51868030,52070090,52100122,22266019,and 21876071)the Science and Technology Planning Project of Yunnan Province (Nos.202001AU070031,202101BE070001-030,and 202101BC070001-009)Applied Basic Research Program of Yunnan Province (No.2019FD043)。
文摘To investigate the enhancing effect of Mn on the performance of simultaneous catalytic oxidation of AsH_(3)and PH_(3)by CuO-Al_(2)O_(3)in a reducing atmosphere under micro-oxygen conditions,Cu-Mn modifiedγ-Al_(2)O_(3)catalysts were prepared.The characteristics of the catalysts showed that Mn reduced the crystallinity of the active CuO component,increased the number of oxygen vacancies and acidic sites on the catalyst surface,enhanced the mobility of surface oxygen,and the interaction between copper and manganese promoted the redox cycling ability of the catalysts and improved their oxidation performance,which increased the conversion frequency(TOF)by 2.54×10^(-2)to 3.07×10^(-2)sec^(-1).On the other hand,the introduction of Mn reduced the production of phosphate and As_(2)O_(3)on the catalyst surface by30.96%and 44.9%,which reduced the coverage and inerting of the active sites by phosphate and As_(2)O_(3),resulting in an 8 hr(6 hr)improvement in the stability of PH_(3)(AsH_(3))removal.
基金This work was supported by the National Science Foundation of China under Grant No. 50372052, 50588201the National Basic Research Program of China (973 program) under Grant No. 2007CB616906+1 种基金 the Program for Changjiang Scholars and Innovative Research Team in UniversityAustralian Research Council under Grant No. DP0559872, DP0881739.
文摘Nd1.85Ce0.15Cu1-xMnxO4 samples with doping level up to 20% have been synthesized by solid-state reaction method. The influence of Mn on their normal-state transport, crystal structure, superconductivity and magnetic properties has been investigated. For the samples with x〉0.03, magnetization under zero-field cooling indicates that the magnetic state changes from ferromagnetic to paramagnetic at T≈100 K, which can be explained with the interaction between Mn4＋and Mn3＋. The electrical resistivity p of samples increases with Mn doping. For the samples with doping level lower than 0.20, p initially increases with the decrease of temperature, i.e., dp/dt〈0, and then shows superconductivity transition at ≈20 K. The results suggest the coexistence of superconductivity and ferromagnetic ordering in Mn doped Nd1.85Ce0.15CuO4.
基金Supported by the National Natural Science Foundation of China under Grant No 51172012the Fundamental Research Funds for the Central Universities
文摘Antiperovskite compounds Mn3Ag1-xCoxN （x =0.2, 0.5 and 0.8） are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction of Co. However, with the increase of the content of Co, the spin reorientation gradually disappears and the antiferromagnetic transition changes to the ferromagnetic transition at the elevated temperature when x = 0.8. In addition, all of the magnetic phase transitions at the elevated temperature are always accompanied by the abnormal thermal expansion behaviors and an entropy change. Moreover, when x = 0.8, the coefficient of linear expansion is -1.89 × 10^-6 K^-1 （290-310K, △T =20 K）, which is generally considered as the low thermal expansion.
基金Project supported by the National "973"Project (2004CB719503)Project supported by the National Natural ScienceFoundation of China (50502023)
文摘CeO2-ZrO2-MnOx mixed oxide series were prepared by sol-gel method. CO pulse and CO-O2 cycle measurements were carried out to examine the oxygen storage complete capacity （OSCC） and dynamic oxygen storage capacity （OSC） of the samples. The doping method brought about strong interactions between manganese oxide and ceria, both in the bulk and on the surface. Only a small part of Mn cations are incorporated into the ceria lattice to form solid solutions and the remaining are left on the surface as finely dispersed Mn3O4. The OSC behaviors of the materials are influenced by the doping amount of Mn and the solubility of Mn in the CeO2 lattice. The OSC is more easily affected by available contents of oxygen storage components when the measurement frequency is low. Comparatively, the concentration of lattice defects, which affects the mobility of bulk oxygen, is the determining factor under high frequency.
基金financially supported by the National Natural Science Foundation of China (Nos. 51201120 and 51401155)the Science & Technology Coordination & Innovation Project of Shaanxi Province(No. 2016KTZDGY-04-01)the Key Laboratory Program Funded by Shaanxi Provincial Education Department(No.17JS053)
文摘In the present work, ribbon and 2-mm rod samples of Mg-Zn-Ca-Mn alloys were prepared by meltspinning and copper mold injection methods, respectively. Effects of Mn doping on glass-forming ability and corrosion performance in simulated body fluid of Mg65Zn30Ca5 alloy were studied through X-ray diffraction, scanning electron microscopy, differential scanning calorimeter, and electrochemical and immersion tests. Results show that with the Mn addition increasing, all the ribbon samples are completely in amorphous state. However, the microstructure of 2-mm rod samples transfers from fully amorphous for the Mn-free alloy to almost polycrystalline state with precipitated Mg, Mn, and MgZn phases. Glass-forming ability of Mg65Zn30Ca5 alloy is decreased by Mn addition. Results of electrochemical and immersion tests demon- strate that the Mn-doped samples exhibit more negative corrosion potential and larger corrosion current density, suggesting that the corrosion resistance decreases with doping amount of Mn element increasing.
基金the financial support from the Research and Development Plan Project in Key Fields of Guangdong Province(2020B0101030005)Applied Special Project of Guangdong Provincial Science and Technology Plan(2017B090917002)+1 种基金Basic and Applied Basic Research Fund of Guangdong Province(2019B1515120027)Key R&D projects in Guangdong Province(2020B0101030005)。
文摘LiFePO_(4),as a prevailing cathode material for lithium-ion batteries(LIBs),still encounters issues such as intrinsic poor electronic conductivity,inferior Li-ion diffusion kinetic,and two-phase transformation mechanism involving substantial structural rearrangements,resulting in unsatisfactory rate performance.Carbon coating,cation doping,and morphological control have been widely employed to reconcile these issues.Inspired by these,we propose a synthetic route with metal–organic frameworks(MOFs)as self-sacrificial templates to simultaneously realize shape modulation,Mn doping,and N-doped carbon coating for enhanced electrochemical performances.The as-synthesized Li MnxFe1–xPO4/C(x=0,0.25,and0.5)deliver tunable electrochemical behaviors induced by the MOF templates,among which LiMn_(0.25)Fe_(0.75)PO_(4)/C outperforms its counterparts in cyclability(164.7 mA h g^(-1)after 200 cycles at 0.5 C)and rate capability(116.3 mA h g^(-1)at 10 C).Meanwhile,the ex-situ XRD reveals a dominant single-phase solid solution mechanism of LiMn_(0.25)Fe_(0.75)PO_(4)/C during delithiation,contrary to the pristine LiFePO_(4),without major structural reconstruction,which helps to explain the superior rate performance.Furthermore,the density functional theory(DFT)calculations verify the effects of Mn doping and embody the superiority of LiMn_(0.25)Fe_(0.75)PO_(4)/C as a LIB cathode,which well supports the experimental observations.This work provides insightful guidance for the design of tunable MOF-derived mixed transitionmetal systems for advanced LIBs.
基金Funded by the Scientific and Technological Research Projects for Education Department of Hubei Province(Q20161407)
文摘NiCr2O4（NCO）spinel composites with different Mn/Ni atomic ratios（Mn/Ni=0.05,0.10,0.15,and 0.20）were synthesized via solid state reaction method.Phase compositions and microstructure of samples were characterized by X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）.The TG-DSC curves showed that the appropriate baking temperature for Mn-doped NCO spinel preparation was approximately 1 320℃.X-ray diffraction patterns exhibited the formation of NCO spinel with Fd-3m space group.Valence state of the Mn ions was determined from 2p and 3s X-ray photoelectron spectra.Manganese ions were mostly in divalent and trivalent states,and the ratio of Mn^2＋/Mn^3＋was 0.78-0.98.Fourier transform infrared spectroscopy（FTIR）was used to analyze the spectral emissivity of Mn doped NCO spinel.It was revealed that the infrared emissivity of Mn-doped NCO spinel in 1.8-5μm could be significantly enhanced with increasing content of Mn^2＋,reaching as high as 0.9398.Mn-doped NCO spinel showed excellent radiation performance and good prospect in high emissivity applications in the temperature range of 800-1 200℃.
基金support received from Yunnan Fundamental Research Projects(Grant No.202101BC070001-007)the Jiangsu Province Industry-University-Research Cooperation Project(No.BY2022832)the National Natural Science Foundation of China(No.52275339).
文摘The effects of Mn addition(0.005,0.01,0.03,0.05,and 0.07 wt.%)on microstructure,shear mechanical behavior,and interfacial thermal stabilities of SAC305 joints were investigated under isothermal aging temperatures of 170 C with different aging time(0,250,500,and 750 h).It is found that Mn addition can increase fracture energy of joints without decreasing the shear strength.And the microstructures have transformed from the eutectic net-like structure in SAC305 solder joints into the structures based onβ-Sn matrix with intermetallic compounds(IMCs)distributed.By doping 0.07 wt.%Mn,the Cu_(6)Sn_(5) growth along the SAC305/Cu interface during thermal aging can be inhibited to some extent.During isothermal aging at 170°C,the maximum shear force of solder joint decreases continuously with aging time increasing,while the fracture energy rises first and then decreases,reaching the maximum at 500 h compared by that with the microstructure homogenization.Cu_(3)Sn growth between Cu_(3)Sn_(5)/Cu interface has been retarded most at the aging time of 250 h with 0.07 wt.%Mn-doped joints.With the aging time prolonging,the inhibition effect of Mn on CusSn IMC layer becomes worse.The strengthening effect of Mn can be explained by precipitation strengthening,and its mechanical behavior can be predicted by particle strengthening model proposed by Orowan.
基金supported by the Natural Science Foundation of Heilongjiang Province(No.LH2021A012).
文摘Lead-free Bi_(_(0.5))Na_(_(0.5))TiO_(3)(BNT)piezoelectric ceramics have the advantages of large coercive fields and high Curie temperatures.But the improvement of piezoelectric coefficient(d 33)is usually accompanied by a huge sacrifice of depolarization temperature(T d).In this work,a well-balanced performance of d 33 and T d is achieved in MnO_(2)-doped 0.79(Bi_(_(0.5))Na_(_(0.5))TiO_(3))-0.14(Bi_(0.5)K_(0.5)TiO_(3))-0.07BaTiO_(3)ternary ceramics.The in-corporation of 0.25 mol%MnO_(2)enhances the d 33 by more than 40%,while T d remains almost unchanged(i.e.,d 33=181 pC/N,T d=184℃).X-ray diffraction(XRD)shows that an appropriate fraction of the small axis-ratio ferroelectric phase(pseudo-cubic,P c)coexists with the long-range ferroelectric phase(tetrag-onal,T)under this MnO_(2)doping.Piezoelectric force microscopy(PFM)has revealed a special domain configuration,namely large striped and layered macro domains embedded with small nanodomains.This study provides a distinctive avenue to design BNT-based piezoelectric ceramics with high piezoelectric performance and temperature stability.
基金supported by the top talent program of Henan Agricultural University[grant numbers 30501029].
文摘The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.
基金financial support from Natural Science Foundation of Zhejiang Province(LY21B030005)National Natural Science Foundation of China(51702287).
文摘Transition metal sulfides(TMSs)have been regarded as greatly promising electrode materials for supercapacitors because of abundant redox electroactive sites and outstanding conductivity.Herein,we report a self-supported hierarchical Mn doped Co_(9)S_(8)@Co(OH)_(2) nanosheet arrays on nickel foam(NF)substrate by a one-step metal–organic-framework(MOF)engaged approach and a subsequent sulfurization process.Experimental results reveal that the introduction of manganese endows improved electric conductivity,enlarged electrochemical specific surface area,adjusted electronic structure of Co_(9)S_(8)@Co(OH)_(2) and enhanced interfacial activities as well as facilitated reaction kinetics of electrodes.The optimal Mn doped Co_(9)S_(8)@Co(OH)_(2) electrode exhibits an ultrahigh specific capacitance of 3745 F g^(-1) at 1 A g^(-1)(5.618 F cm^(-2) at 1.5 mA cm^(-2))and sustains 1710 F g^(-1) at 30 A g^(-1)(2.565 F cm^(-2) at 45 mA cm^(-2)),surpassing most reported values on TMSs.Moreover,a battery-type asymmetric supercapacitor(ASC)device is constructed,which delivers high energy density of 50.2 Wh kg^(-1) at power density of 800 W kg^(-1),and outstanding long-term cycling stability(94%capacitance retention after 8000 cycles).The encouraging results might offer an effective strategy to optimize the TMSs for energy-storage devices.
基金Supported by NNSFC (Nos 20671092, 20773132, 20771101)National Basic Research Program of China (No 2007BAE08B01, 2009 CB613306)
文摘Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11～15 nm.The incorporation of Mn ions in CeO2 resulted in a lattice volume reduction.Mn ions showed a mixed valence state of ＋2,＋3 and ＋4 in CeO2 lattice.An obvious red-shift of the absorption threshold edge was observed from the UV-visible spectrum.Compared with the bulk CeO2,Ce1-xMnxO2-δ nanocrystals exhibited a lower releasing oxygen temperature as indicated by TPR technique.
基金Project supported by the National Natural Science Foundation of China(Nos.51632005 and 51371194)National Basic Research Program of China(Grant No.2013CB632500)
文摘CuIn1-xMnxTe2 samples have been synthesized by a melt-annealing method. The x-ray powder diffraction（XRD）analysis shows that the CuIn1-xMnxTe2 samples crystallize in the chalcopyrite phase. Mn doping can effectively optimize the electrical properties and accordingly improve the power factor. The room temperature electrical conductivity of doped CuInTe2 increases by several orders of magnitude due to substituting In with Mn. In addition, a large reduction in thermal conductivity is achieved through the enhanced phonon scattering via Mn-related point defects and precipitates. Therefore,an enhanced average ZT value up to 0.34 is achieved for sample CuIn0.925Mn0.075Te2, which is 41% higher than that of the pristine CuInTe2.
基金supported by the National Natural Science Foundation of China(Grant Nos.11274322,51402318,61404080,and 61675066)the National Key Technology Research and Development Program of China(Grant No.2016YFA0201102)the China Postdoctoral Science Foundation(Grant No.2016LH0050)
文摘As a low-bandgap ferroelectric material, BiFeO3 has gained wide attention for the potential photovoltaic applications,since its photovoltaic effect in visible light range was reported in 2009. In the present work, Bi（Fe, Mn）O3thin films are fabricated by pulsed laser deposition method, and the effects of Mn doping on the microstructure, optical, leakage,ferroelectric and photovoltaic characteristics of Bi（Fe, Mn）O3 thin films are systematically investigated. The x-ray diffraction data indicate that Bi（Fe, Mn）O3 thin films each have a rhombohedrally distorted perovskite structure. From the light absorption results, it follows that the band gap of Bi（Fe, Mn）O3 thin films can be tuned by doping different amounts of Mn content. More importantly, photovoltaic measurement demonstrates that the short-circuit photocurrent density and the open-circuit voltage can both be remarkably improved through doping an appropriate amount of Mn content, leading to the fascinating fact that the maximum power output of ITO/BiFe（0.7）Mn（0.3）O3/Nb-STO capacitor is about 175 times higher than that of ITO/BiFeO3/Nb-STO capacitor. The improvement of photovoltaic response in Bi（Fe, Mn）O3 thin film can be reasonably explained as being due to absorbing more visible light through bandgap engineering and maintaining the ferroelectric property at the same time.
基金financially supported by the National Natural Science Foundation of China(No.50502005)Beijing Natural Science Foundation(No.1092014)+2 种基金Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University(LZUMMM2010002)Metallurgy Foundation of University of Science and Technology Beijingsupported by Program for New Century Excellent Talents in University(No.NCET-070065)
文摘Large-scale flower-shaped Mn doped ZnO nanostructures have been grown on silicon substrates by simple thermal evaporation at atmospheric pressure.The flower-shaped nanostructure makes up of many nanorods,which are rooted in one center.Analysis of X-ray diffraction,high-resolution transmission electron microscopy and Raman spectra results reveal that the products are of single phase with wurtzite structure.Elemental mapping results show that no impurity clusters exist in the doped materials.The photoluminescence spectra demonstrate that many oxygen vacancies exist in the doped materials,and the crystal quality is improved and the content of oxygen vacancies is decreased by annealing treatment.The flower-shaped Mn doped ZnO nanostructures exhibit ferromagnetic ordering above room temperature,and its magnetization is decreased by the annealing treatment,which indicates that the magnetic behavior of the doped materials may be related to the interaction between Mn doping and the oxygen vacancies.
基金Project supported by the National Natural Science Foundation of China (Grant No 50871120)
文摘Zn1-xMnxO bulks have been prepared by the solid state reaction method. Zn vapor treatment has been carried out to adjust the carrier concentration. For the Zn treated Zn1-xMnxO bulks, analysis of the temperature dependence of resistance and the field dependence of magnetoresistance demonstrates that the bound magnetic polarons （BMPs） play an important role in the electrical transport behavior. The hopping of BMPs dominates the electrical conduction behavior when temperature is below 170 K. At low temperature, paramagnetic Zn1-xMnxO bulks show a large magnetoresistance effect, which indicates that the large magnetoresistance effect in transition-metal doped ZnO dilute magnetic semiconductors is independent of their magnetic states.
