Co-precipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases, it can be exploited. The Zn0.5Mn0.5−xLi2xFe2O4 nanomaterials (x = 0.0, 0.1, 0.2, 0.3 and 0.4) wa...Co-precipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases, it can be exploited. The Zn0.5Mn0.5−xLi2xFe2O4 nanomaterials (x = 0.0, 0.1, 0.2, 0.3 and 0.4) was afforded by utilizing co-precipitation method. The structural and optical characteristics were analyzed for the samples employing X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and Ultraviolet-visible spectrophotometer (UV-Vis). XRD revealed that the structure of certain nanoparticles is a cubic spinel with space group (Fd-3m) and crystallite size in the scale 124 - 150 nm. Lattice parameter was determined to increments with Li+1 and that may occur due to the larger ionic radius of the Li1+ ion. FTIR spectroscopy confirmed the form of spinel ferrite and explicated the properties of absorption bands approximately 593, 1111, 1385, 1640, 2922 and 3430. The energy band gap was estimated for all samples with diverse ratios and was observed in the range of 2.58 - 2.52 eV.展开更多
Sodium-ion batteries(SIBs)are regarded as the most promising technology for large-scale energy storage systems.However,the practical application of SIBs is still hindered by the lack of applicable cathode materials.He...Sodium-ion batteries(SIBs)are regarded as the most promising technology for large-scale energy storage systems.However,the practical application of SIBs is still hindered by the lack of applicable cathode materials.Herein,a novel phase-pure polyanionic Na_(8)Fe_(5)(SO_(4))_(9) is designed and employed as a cathode material for SIBs for the first time.The Na_(8)Fe_(5)(SO_(4))_(9) has an alluaudite-type sulfate framework and small Naþion diffusion barriers.As expected,the as-synthesized Na_(8)Fe_(5)(SO_(4))_(9)@rGO exhibits a high working potential of 3.8 V(versus Na/Naþ),a superior reversible capacity of 100.2 mAh g1 at 0.2 C,excellent rate performance(~80 mAh g1 at 10 C,~63 mAh g1 at 50 C),and an ultra-long cycling life(91.9%capacity retention after 10,000 cycles at 10 C,81%capacity retention after 20,000 cycles at 50 C).We use various techniques and computational methods to comprehensively investigate the electrochemical reaction mechanisms of Na_(8)Fe_(5)(SO_(4))_(9)@rGO.展开更多
Piezocatalytic activation of persulfate(PS) has great application potential in environmental remediation;however,the relationship between piezocatalyst thickness and catalytic activity is not clear,limiting the furthe...Piezocatalytic activation of persulfate(PS) has great application potential in environmental remediation;however,the relationship between piezocatalyst thickness and catalytic activity is not clear,limiting the further improvement of catalytic activity and application of the technology.Herein,the Bi_(2)Fe_(4)O_(9)(BFO) piezocatalysts with tunable thickness were prepared through a facile hydrothermal method by tuning the molar ratio of Bi(NO_(3)),5H_(2)O and FeCl_(3)·6H_(2)O for piezocatalytic activation of peroxydisulfate(PDS).The BFO with the smallest thickness exhibits excellent catalytic activity,and the SO_(4)^(·-)and ·OH are the major reactive oxygen species for degrading organic pollutants.Further XPS investigations and finite element analyses demonstrate that the decreased thickness of BFO not only exposes more Fe^(2+)sites for PDS activation,but also improve the piezoelectric effect to accelerate the regeneration of Fe^(2+),thus enabling an enhanced synergy effect between PDS activation and piezocatalysis for outstanding catalytic activity.This work provides an understanding of the relationship between thickness of piezocatalysts and its catalytic activity over PDS activation,facilitating the development of more efficient piezocatalysts and PS-based advanced oxidation processes.展开更多
Bismuth ferrite（Bi_2Fe_4O_9） thin films were grown on p-type Si（100） substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscop...Bismuth ferrite（Bi_2Fe_4O_9） thin films were grown on p-type Si（100） substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy studies revealed that the grown films have single-phase polycrystalline nature and are crystallized in orthorhombic structure. The grain size of the grown thin films was found to increase（56–130 nm） with sputtering power. Atomic force microscopy images clearly illustrated that the grown thin films have smooth surface. Energy-dispersive X-ray analysis revealed the presence of Bi, Fe and O elements with desired ratio and also the absence of impurities in the grown films. Analysis of ferroelectric hysteresis loops revealed that the remanent polarization and coercive field increase with the increase in sputtering power. Vicker＇s hardness analysis showed that the hardness of films strongly depends on the grain size and film thickness, which are mainly determined by the sputtering power. The above observations revealed that Bi_2Fe_4O_9 thin film deposited at higher sputtering power has good crystallinity and shows better electrical properties.展开更多
High-frequency soft magnetic ferrite ceramics are desired in miniaturized and efficient power electronics but remain extremely challenging to deploy on account of the power loss(Pcv)at megahertz frequencies.Here,we pr...High-frequency soft magnetic ferrite ceramics are desired in miniaturized and efficient power electronics but remain extremely challenging to deploy on account of the power loss(Pcv)at megahertz frequencies.Here,we prepared NiCuZn ferrite with superior high-frequency properties by V_(2)O_(5)and Bi_(2)O_(3)synergistic doping,which proves to be a potent pathway to reduce Pcv of the ferrite at megahertz frequencies.The sample doped with 800 ppm V_(2)O_(5)and 800 ppm Bi_(2)O_(3)yielded the most optimized magnetic properties with a Pcv of 113 kW/m^(3)(10 MHz,5 mT,25℃),an initial permeability(μi)of 89,and a saturation induction(Bs)of 340 mT,which is at the forefront of the reported results.These outstanding properties are closely related to the notable grain boundary structure,which features a new type of nano-Bi_(2)Fe_(4)O_(9)phase around ferrite grains and a Ca/Si/V/O amorphous layer.Our results indicate great strides in correlating the grain boundary structure with multiple-ion doping and set the scene for the developing high-frequency soft magnet ferrites.展开更多
文摘Co-precipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases, it can be exploited. The Zn0.5Mn0.5−xLi2xFe2O4 nanomaterials (x = 0.0, 0.1, 0.2, 0.3 and 0.4) was afforded by utilizing co-precipitation method. The structural and optical characteristics were analyzed for the samples employing X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and Ultraviolet-visible spectrophotometer (UV-Vis). XRD revealed that the structure of certain nanoparticles is a cubic spinel with space group (Fd-3m) and crystallite size in the scale 124 - 150 nm. Lattice parameter was determined to increments with Li+1 and that may occur due to the larger ionic radius of the Li1+ ion. FTIR spectroscopy confirmed the form of spinel ferrite and explicated the properties of absorption bands approximately 593, 1111, 1385, 1640, 2922 and 3430. The energy band gap was estimated for all samples with diverse ratios and was observed in the range of 2.58 - 2.52 eV.
基金support from the National Nature Science Foundation of China(Nos.U20A20249,21972108,and 22209125).
文摘Sodium-ion batteries(SIBs)are regarded as the most promising technology for large-scale energy storage systems.However,the practical application of SIBs is still hindered by the lack of applicable cathode materials.Herein,a novel phase-pure polyanionic Na_(8)Fe_(5)(SO_(4))_(9) is designed and employed as a cathode material for SIBs for the first time.The Na_(8)Fe_(5)(SO_(4))_(9) has an alluaudite-type sulfate framework and small Naþion diffusion barriers.As expected,the as-synthesized Na_(8)Fe_(5)(SO_(4))_(9)@rGO exhibits a high working potential of 3.8 V(versus Na/Naþ),a superior reversible capacity of 100.2 mAh g1 at 0.2 C,excellent rate performance(~80 mAh g1 at 10 C,~63 mAh g1 at 50 C),and an ultra-long cycling life(91.9%capacity retention after 10,000 cycles at 10 C,81%capacity retention after 20,000 cycles at 50 C).We use various techniques and computational methods to comprehensively investigate the electrochemical reaction mechanisms of Na_(8)Fe_(5)(SO_(4))_(9)@rGO.
基金financially supported by the National Natural Science Foundation of China (Nos.52170155 and 52100084)。
文摘Piezocatalytic activation of persulfate(PS) has great application potential in environmental remediation;however,the relationship between piezocatalyst thickness and catalytic activity is not clear,limiting the further improvement of catalytic activity and application of the technology.Herein,the Bi_(2)Fe_(4)O_(9)(BFO) piezocatalysts with tunable thickness were prepared through a facile hydrothermal method by tuning the molar ratio of Bi(NO_(3)),5H_(2)O and FeCl_(3)·6H_(2)O for piezocatalytic activation of peroxydisulfate(PDS).The BFO with the smallest thickness exhibits excellent catalytic activity,and the SO_(4)^(·-)and ·OH are the major reactive oxygen species for degrading organic pollutants.Further XPS investigations and finite element analyses demonstrate that the decreased thickness of BFO not only exposes more Fe^(2+)sites for PDS activation,but also improve the piezoelectric effect to accelerate the regeneration of Fe^(2+),thus enabling an enhanced synergy effect between PDS activation and piezocatalysis for outstanding catalytic activity.This work provides an understanding of the relationship between thickness of piezocatalysts and its catalytic activity over PDS activation,facilitating the development of more efficient piezocatalysts and PS-based advanced oxidation processes.
文摘Bismuth ferrite（Bi_2Fe_4O_9） thin films were grown on p-type Si（100） substrate by radio-frequency magnetron sputtering at 873 K. X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy studies revealed that the grown films have single-phase polycrystalline nature and are crystallized in orthorhombic structure. The grain size of the grown thin films was found to increase（56–130 nm） with sputtering power. Atomic force microscopy images clearly illustrated that the grown thin films have smooth surface. Energy-dispersive X-ray analysis revealed the presence of Bi, Fe and O elements with desired ratio and also the absence of impurities in the grown films. Analysis of ferroelectric hysteresis loops revealed that the remanent polarization and coercive field increase with the increase in sputtering power. Vicker＇s hardness analysis showed that the hardness of films strongly depends on the grain size and film thickness, which are mainly determined by the sputtering power. The above observations revealed that Bi_2Fe_4O_9 thin film deposited at higher sputtering power has good crystallinity and shows better electrical properties.
基金This work was supported by the National Natural Science Foundation of China(Nos.52002103 and 52027802)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK209907299001-022)the Key Research and Development Program of Zhejiang Province(Nos.2020C01008,2021C01023,2021C01192,and 2021C01193).
文摘High-frequency soft magnetic ferrite ceramics are desired in miniaturized and efficient power electronics but remain extremely challenging to deploy on account of the power loss(Pcv)at megahertz frequencies.Here,we prepared NiCuZn ferrite with superior high-frequency properties by V_(2)O_(5)and Bi_(2)O_(3)synergistic doping,which proves to be a potent pathway to reduce Pcv of the ferrite at megahertz frequencies.The sample doped with 800 ppm V_(2)O_(5)and 800 ppm Bi_(2)O_(3)yielded the most optimized magnetic properties with a Pcv of 113 kW/m^(3)(10 MHz,5 mT,25℃),an initial permeability(μi)of 89,and a saturation induction(Bs)of 340 mT,which is at the forefront of the reported results.These outstanding properties are closely related to the notable grain boundary structure,which features a new type of nano-Bi_(2)Fe_(4)O_(9)phase around ferrite grains and a Ca/Si/V/O amorphous layer.Our results indicate great strides in correlating the grain boundary structure with multiple-ion doping and set the scene for the developing high-frequency soft magnet ferrites.
