Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ a...Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ and LaPO_4∶Eu 3+ were synthesized by in-situ co-precipitation method. X-ray diffraction and scanning electronic micrograph were used to characterize the resultant samples, whose particle size are in the range of micrometer. The emission spectra of Zn_3(PO_4)_2∶Eu 3+ (λ_ ex=245 nm) and LaPO_4∶Eu 3+ (λ_ ex=390 nm) shows that the emission for Eu 3+ in Zn_3(PO_4)_2 is dominated by the 5D_0→7F_1 (592 nm) magnetic-dipole transition,While the dominant emission for Eu 3+ in LaPO_4 is the typical hypersensitive transition 5D_0→7F_2 (618 nm).展开更多
Objective To study the structural and anticorrosive property of microcrystalline α-Zn_3(PO_4)_2·4H_2O. Methods Zinc phosphate was prepared from zinc acetate and orthophosphate acid in aqueous solution. Structura...Objective To study the structural and anticorrosive property of microcrystalline α-Zn_3(PO_4)_2·4H_2O. Methods Zinc phosphate was prepared from zinc acetate and orthophosphate acid in aqueous solution. Structural characteristics of products were investigated by XRD, RAMAN, FTIR, TG-DTA, SEM, surface area, particle size distribution, and density measurements. Results The title compound, a highly crystalline, micronized and lamellar α-Zn_3(PO_4)_2·4H_2O, has an orthorhombic monoclinic system, space group a_0=10.597(),b_ 0 =18.308(), c_ 0 =5.0304(), V=975.86 3. Its specific area is 0.701m2/g, density 3.1612g/m3, and average size 4.75μm . Conclusion Comparing with commercial Zinc phosphate, the synthesized lamellar microcrystalline zinc phosphate had excellent anticorrosive property and dispersibility.展开更多
以五氧化二钒干凝胶、碳酸锰、磷酸二氢铵、碳酸锂、乙炔黑为原料,采用固相法在相对较低的温度条件下合成了x Li Mn PO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和表面形貌进行表征...以五氧化二钒干凝胶、碳酸锰、磷酸二氢铵、碳酸锂、乙炔黑为原料,采用固相法在相对较低的温度条件下合成了x Li Mn PO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和表面形貌进行表征。结果表明,750℃下烧结15 h合成的3Li Mn PO4·Li3V2(PO4)3为结晶良好的两相结构,颗粒粒径较小且分布比较均匀,其在室温、0.2 C倍率下首次充放电容量分别为144.8 m Ah/g和139.8 m Ah/g,循环50次后容量为130.5 m Ah/g。展开更多
Sodium ion batteries （SIBs） are very promising for large-scale energy storage in virtue of its high energy density, abundant sodium resources and low environmental impact, etc. However, it is still a big chal- lenge...Sodium ion batteries （SIBs） are very promising for large-scale energy storage in virtue of its high energy density, abundant sodium resources and low environmental impact, etc. However, it is still a big chal- lenge to develop high-performance and durable cathode materials for SIBs. Among different candidate materials, Na_3V_2（PO_4）_3 has attracted great attentions due to its high theoretical capacity （117 mAh/g）, stable framework structure and excellent ionic conductivity. However, Na_3V_2（PO_4）_3 delivers inferior rate capability and cycling stability due to its poor electronic conductivity. In this work, free-standing Na_3V_2（PO_4）_3/carbon nanofiber membranes are synthesized by an electrospinning-sintering mute. The sample could deliver excellent cycling capability with specific capacity of 112 mAh/g at 1 C after 250 cycles and ultrahigh rate capability with 76.9 mAh/g even at 100 C, which is superior to many state-of- the-art SIB cathode materials. This can be attributed to the hierarchically distributed Na_3V_2（PO_4）_3 crystals in carbon nanofiber network, which possesses outstanding electronicfionic conductivity and thus leads to an ultrahigh rate capabilitY.展开更多
The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen supply.However,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O...The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen supply.However,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O required to ensure complete hydrolysis are two key challenges for the MgH_(2) hydrolysis systems.Now,a low-cost method is reported to synthesize MgH_(2)@Mg(BH_(4))_(2) composite via ball-milling MgH_(2) with cheap and widely available B_(2)O_(3)(or B(OH)_(3)).By adding small amounts of B_(2)O_(3),the in-situ formed Mg(BH_(4))_(2) could significantly promote the hydrolysis of MgH_(2).In particular,the MgH_(2)–10 wt%B_(2)O_(3) composite releases 1330.7 mL·g^(−1) H_(2)(close to 80%theoretical hydrogen generation H_(2))in H_(2)O and 1520.4 mL·g^(−1) H_(2)(about 95%)in 0.5 M MgCl_(2) in 60 min at 26℃ with hydrolysis rate of 736.9 mL·g^(−1)·min^(−1) and 960.9 mL·g^(−1)·min^(−1) H_(2) during the first minute of the hydrolysis,respectively.In addition,the MgCl_(2) solution allows repeated use by filtering and exhibits high cycle stability(20 cycles),therefore leading to much reduced capacity loss caused by the excess H_(2)O.We show that by introducing B_(2)O_(3) and recycling the 0.5 M MgCl_(2) solution,the system hydrogen capacity can approach 5.9 wt%,providing a promising hydrogen generation scheme to supply hydrogen to the fuel cells.展开更多
With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen...With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.展开更多
文摘Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ and LaPO_4∶Eu 3+ were synthesized by in-situ co-precipitation method. X-ray diffraction and scanning electronic micrograph were used to characterize the resultant samples, whose particle size are in the range of micrometer. The emission spectra of Zn_3(PO_4)_2∶Eu 3+ (λ_ ex=245 nm) and LaPO_4∶Eu 3+ (λ_ ex=390 nm) shows that the emission for Eu 3+ in Zn_3(PO_4)_2 is dominated by the 5D_0→7F_1 (592 nm) magnetic-dipole transition,While the dominant emission for Eu 3+ in LaPO_4 is the typical hypersensitive transition 5D_0→7F_2 (618 nm).
文摘Objective To study the structural and anticorrosive property of microcrystalline α-Zn_3(PO_4)_2·4H_2O. Methods Zinc phosphate was prepared from zinc acetate and orthophosphate acid in aqueous solution. Structural characteristics of products were investigated by XRD, RAMAN, FTIR, TG-DTA, SEM, surface area, particle size distribution, and density measurements. Results The title compound, a highly crystalline, micronized and lamellar α-Zn_3(PO_4)_2·4H_2O, has an orthorhombic monoclinic system, space group a_0=10.597(),b_ 0 =18.308(), c_ 0 =5.0304(), V=975.86 3. Its specific area is 0.701m2/g, density 3.1612g/m3, and average size 4.75μm . Conclusion Comparing with commercial Zinc phosphate, the synthesized lamellar microcrystalline zinc phosphate had excellent anticorrosive property and dispersibility.
文摘以五氧化二钒干凝胶、碳酸锰、磷酸二氢铵、碳酸锂、乙炔黑为原料,采用固相法在相对较低的温度条件下合成了x Li Mn PO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和表面形貌进行表征。结果表明,750℃下烧结15 h合成的3Li Mn PO4·Li3V2(PO4)3为结晶良好的两相结构,颗粒粒径较小且分布比较均匀,其在室温、0.2 C倍率下首次充放电容量分别为144.8 m Ah/g和139.8 m Ah/g,循环50次后容量为130.5 m Ah/g。
基金the financial support from the 973 program of China (Grant No. 2014CB932401, 2015CB932500)Beijing Nova Program (Grant No. Z161100004916099)the Tsinghua University Initiative Scientific Research Program (Grant Nos. 20173080001, 20151080367)
文摘Sodium ion batteries （SIBs） are very promising for large-scale energy storage in virtue of its high energy density, abundant sodium resources and low environmental impact, etc. However, it is still a big chal- lenge to develop high-performance and durable cathode materials for SIBs. Among different candidate materials, Na_3V_2（PO_4）_3 has attracted great attentions due to its high theoretical capacity （117 mAh/g）, stable framework structure and excellent ionic conductivity. However, Na_3V_2（PO_4）_3 delivers inferior rate capability and cycling stability due to its poor electronic conductivity. In this work, free-standing Na_3V_2（PO_4）_3/carbon nanofiber membranes are synthesized by an electrospinning-sintering mute. The sample could deliver excellent cycling capability with specific capacity of 112 mAh/g at 1 C after 250 cycles and ultrahigh rate capability with 76.9 mAh/g even at 100 C, which is superior to many state-of- the-art SIB cathode materials. This can be attributed to the hierarchically distributed Na_3V_2（PO_4）_3 crystals in carbon nanofiber network, which possesses outstanding electronicfionic conductivity and thus leads to an ultrahigh rate capabilitY.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong Province(No.2022A1515011832 and 2021A1515110676)supported by GDAS’Project of Science and Technology Development(2022GDASZH-2022010104,2022GDASZH-2022030604-04).
文摘The hydrolysis of MgH_(2) delivers high hydrogen capacity(15.2 wt%),which is very attractive for real-time hydrogen supply.However,the formation of a surface passivation Mg(OH)_(2) layer and the large excess of H_(2)O required to ensure complete hydrolysis are two key challenges for the MgH_(2) hydrolysis systems.Now,a low-cost method is reported to synthesize MgH_(2)@Mg(BH_(4))_(2) composite via ball-milling MgH_(2) with cheap and widely available B_(2)O_(3)(or B(OH)_(3)).By adding small amounts of B_(2)O_(3),the in-situ formed Mg(BH_(4))_(2) could significantly promote the hydrolysis of MgH_(2).In particular,the MgH_(2)–10 wt%B_(2)O_(3) composite releases 1330.7 mL·g^(−1) H_(2)(close to 80%theoretical hydrogen generation H_(2))in H_(2)O and 1520.4 mL·g^(−1) H_(2)(about 95%)in 0.5 M MgCl_(2) in 60 min at 26℃ with hydrolysis rate of 736.9 mL·g^(−1)·min^(−1) and 960.9 mL·g^(−1)·min^(−1) H_(2) during the first minute of the hydrolysis,respectively.In addition,the MgCl_(2) solution allows repeated use by filtering and exhibits high cycle stability(20 cycles),therefore leading to much reduced capacity loss caused by the excess H_(2)O.We show that by introducing B_(2)O_(3) and recycling the 0.5 M MgCl_(2) solution,the system hydrogen capacity can approach 5.9 wt%,providing a promising hydrogen generation scheme to supply hydrogen to the fuel cells.
基金supported by the National Natural Science Foundation of China (No.52364022)the Natural Science Foundation of Guangxi Province,China (Nos.2023JJA160192 and 2021GXNSFAA220096)+1 种基金the Guangxi Science and Technology Major Project,China (No.AA23073018)the Guangxi Chongzuo Science and Technology Plan,China (No.2023ZY00503).
文摘With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.
