The effect of substitution of Fe^(3+) by Al^(3+) on the structure and magnetic properties of NdAl_(x)Fe_(1-x)O_(3) perovskite nano-powders(x=0.0,0.1,0.2,0.3,0.4,and 0.5) prepared by the glycine-nitrate auto-combustion...The effect of substitution of Fe^(3+) by Al^(3+) on the structure and magnetic properties of NdAl_(x)Fe_(1-x)O_(3) perovskite nano-powders(x=0.0,0.1,0.2,0.3,0.4,and 0.5) prepared by the glycine-nitrate auto-combustion method was studied.All samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),and energy dispersive X-ray spectroscopy(EDX).The magnetic properties of the samples were investigated using a vibrating sample magnetometer(VSM).The X-ray results for all samples reveal the formation of an orthorhombic perovskite phase(space group Pbnm) with no secondary phase.The crystallite sizes of the nanoparticles are found to decrease with increasing Al content,and are in the range of 53-38 nm.SEM images show spherical nanoparticles with agglomeration.The FT-IR spectra confirm the presence of metal oxygen bonds.The M-H loop of the pristine NdFeO_(3) sample is antiferromagnetic in the a b plane with weak ferromagnetism in the c-axis.Introducing AI inclusions in the pristine polycrystal thereby creating magnetic vacancies is seen to influence the magnetic properties.The magnetic dilution results in enhanced magnetisation at low Al content;x=0.1,0.2(saturation magnetisation being 2.08 and 2.05 emu/g,respectively) compared to the pristine sample with a saturation magnetisation of 1.43 emu/g due to increased exchange interaction.Also dilution with nonmagnetic dopant induces the phase transition from weak ferromagnetic to paramagnetic depending on the impurity concentration.The coercive field for NdFeO_(3) is found to be equal to 1950 Oe and decreases with Al-substitution.These findings lay a ground work for research in tuning magnetic properties and in spintronics with potential applications in data storage,switches and electronic devices.展开更多
Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and was...Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and wastewaters,and its high content jeopardizes the efficacy of Advanced oxidation process(AOPs).Thus,a novel chlorine ion resistant catalyst Bsite Ru doped LaFe_(1-x)Ru_(x)O_(3-)δin CWAO treatment of chlorine ion wastewater was examined.Especially,LaFe_(0.85)Ru_(0.15)O_(3-δ)was 45.5% better than that of the 6%RuO_(2)@TiO_(2)(commercial carrier)on total organic carbon(TOC)removal.Also,doped catalysts LaFe_(1-x)Ru_(x)O_(3-)δshowed better activity than supported catalysts RuO_(2)@LaFeO_(3) and RuO_(2)@TiO_(2) with the same Ru content.Moreover,LaFe_(0.85)Ru_(0.15)O_(3-)δhas novel chlorine ion resistance no matter the concentration of Cl^(−) and no Ru dissolves after the reaction.X-ray diffraction(XRD)refinement,X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),and X-ray absorption fine structure(XAFS)measurements verified the structure of LaFe_(0.85)Ru_(0.15)O_(3-)δ.Kinetic data and density functional theory(DFT)proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions.The existence of Fe in LaFe_(0.85)Ru_(0.15)O_(3-)δcould adsorb chlorine ion(catalytic activity inhibitor),which can protect the Ru site and other active oxygen species to exert catalytic activity.This work is essential for the development of chloride-resistant catalyst in CWAO.展开更多
文摘The effect of substitution of Fe^(3+) by Al^(3+) on the structure and magnetic properties of NdAl_(x)Fe_(1-x)O_(3) perovskite nano-powders(x=0.0,0.1,0.2,0.3,0.4,and 0.5) prepared by the glycine-nitrate auto-combustion method was studied.All samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),and energy dispersive X-ray spectroscopy(EDX).The magnetic properties of the samples were investigated using a vibrating sample magnetometer(VSM).The X-ray results for all samples reveal the formation of an orthorhombic perovskite phase(space group Pbnm) with no secondary phase.The crystallite sizes of the nanoparticles are found to decrease with increasing Al content,and are in the range of 53-38 nm.SEM images show spherical nanoparticles with agglomeration.The FT-IR spectra confirm the presence of metal oxygen bonds.The M-H loop of the pristine NdFeO_(3) sample is antiferromagnetic in the a b plane with weak ferromagnetism in the c-axis.Introducing AI inclusions in the pristine polycrystal thereby creating magnetic vacancies is seen to influence the magnetic properties.The magnetic dilution results in enhanced magnetisation at low Al content;x=0.1,0.2(saturation magnetisation being 2.08 and 2.05 emu/g,respectively) compared to the pristine sample with a saturation magnetisation of 1.43 emu/g due to increased exchange interaction.Also dilution with nonmagnetic dopant induces the phase transition from weak ferromagnetic to paramagnetic depending on the impurity concentration.The coercive field for NdFeO_(3) is found to be equal to 1950 Oe and decreases with Al-substitution.These findings lay a ground work for research in tuning magnetic properties and in spintronics with potential applications in data storage,switches and electronic devices.
基金supported by the Natural Science Foundation of Liaoning Province (No. 2020-BS-012)the National Natural Science Foundation of China (No. 51878643)+2 种基金the Dalian Institute of Chemical Physics & Qingdao Institute of Bioenergy and Bioprocess Technology (DICP&QIBEBT) (No. UN201809)the Scientific Research Common Program of Beijing Municipal Commission of Education (No. KM202010017006)Talents Project of Beijing Organization Department (No. 2018000020124G091)。
文摘Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and wastewaters,and its high content jeopardizes the efficacy of Advanced oxidation process(AOPs).Thus,a novel chlorine ion resistant catalyst Bsite Ru doped LaFe_(1-x)Ru_(x)O_(3-)δin CWAO treatment of chlorine ion wastewater was examined.Especially,LaFe_(0.85)Ru_(0.15)O_(3-δ)was 45.5% better than that of the 6%RuO_(2)@TiO_(2)(commercial carrier)on total organic carbon(TOC)removal.Also,doped catalysts LaFe_(1-x)Ru_(x)O_(3-)δshowed better activity than supported catalysts RuO_(2)@LaFeO_(3) and RuO_(2)@TiO_(2) with the same Ru content.Moreover,LaFe_(0.85)Ru_(0.15)O_(3-)δhas novel chlorine ion resistance no matter the concentration of Cl^(−) and no Ru dissolves after the reaction.X-ray diffraction(XRD)refinement,X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),and X-ray absorption fine structure(XAFS)measurements verified the structure of LaFe_(0.85)Ru_(0.15)O_(3-)δ.Kinetic data and density functional theory(DFT)proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions.The existence of Fe in LaFe_(0.85)Ru_(0.15)O_(3-)δcould adsorb chlorine ion(catalytic activity inhibitor),which can protect the Ru site and other active oxygen species to exert catalytic activity.This work is essential for the development of chloride-resistant catalyst in CWAO.
