Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and...Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and anchor on the surface of Ti_(3)C_(2)T_(x) via the strong Co-F bonds and contribute tremendously to depress Ti_(3)C_(2)T_(x) self-restacking.Profiting from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti_(3)C_(2)T_(x) as well as outstanding stability of the as-designed nanostructure,the optimum Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x)electrode reaches a commendable specific capacitance(up to 3800 mF·cm^(−2)),great rate capability(80%capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4%/85.5%retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) and active carbon can deliver a high energy density of 84.0μWh·cm^(−2) at the power energy of 3.2 mW·cm^(−2),and excellent cycling durability with 87.0%of initial capacitance retention upon 20,000 loops.This work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor.展开更多
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
Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM...Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m^(-2),equaling to a weight percentage around 4.5%.It has been revealed that the quantities of surface active oxygen(O_(2)^(-))and acid sites are crucial for the reaction,which can adsorb and activate NO_(x)and NH_(3)reactants effectively.Below the monolayer dispersion threshold,Co_(3)O_(4)is finely dispersed as sub-monolayers or monolayers and in an amorphous state,which is favorable to generate the two kinds of active sites,hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide.However,the formation of crystalline Co_(3)O_(4)above the capacity is harmful to the reaction performance.4%Co_(3)O_(4)/ZSM-5,the catalyst close to the monolayer dispersion capacity,possesses the most abundant active O_(2)^(-)species and acidic sites,thereby demonstrating the best reaction performance in all the samples.It is proposed the optimal Co_(3)O_(4)/ZSM-5 catalyst can be prepared by loading the capacity amount of Co_(3)O_(4)onto HZSM-5 support.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting metho...Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.展开更多
The Li_(4+x)Al_xSi_(1-x)O_(4-y)Al_2O_3 (x = 0 to 0.5, y = 0 to 0.5) ionconductors were prepared by the Sol-Gel method and examined in detail. The powder and sinteredsamples were characterized by TG-DTA, XRD, SEM, and ...The Li_(4+x)Al_xSi_(1-x)O_(4-y)Al_2O_3 (x = 0 to 0.5, y = 0 to 0.5) ionconductors were prepared by the Sol-Gel method and examined in detail. The powder and sinteredsamples were characterized by TG-DTA, XRD, SEM, and AC impedance techniques. The experimentalresults show that the conductivity and sinterability increase with the amount of excess Al_2O_3 inthe silicate. The particle size of the powder samples is about 0.13 μm. The maximum conductivity at18 ℃ is 3.057 * 10^(-5) s/cm for Li_(4.4)Al_(0.4)Si_(0.6)O_4-0.3 Al_2O_3.展开更多
NASICON型快离子导体Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)(LATP)具有较高的离子电导率、较宽的电化学窗口及良好的水和空气稳定性,但其界面接触性能差。石榴石型Li_(7)La_(3)Zr_(2)O_(12)(LLZO)锂离子电导率高、电化学窗口较宽且热稳定...NASICON型快离子导体Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)(LATP)具有较高的离子电导率、较宽的电化学窗口及良好的水和空气稳定性,但其界面接触性能差。石榴石型Li_(7)La_(3)Zr_(2)O_(12)(LLZO)锂离子电导率高、电化学窗口较宽且热稳定性好,但其立方相结构不稳定,影响其实际应用。采用溶液浇筑法,制备纯PVDF-LiTFSI电解质膜和以PVDF为基、3种不同质量比的Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)的固态电解质膜,并探讨纯PVDF-LiTFSI电解质膜和3种不同质量比的活性无机电解质填料对复合固态电解质离子电导率的影响。结果表明,Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为1∶1时,电解质膜的XRD图谱的衍射峰比纯PVDF-LiTFSI下降更为明显,电化学窗口为3.9 V左右,表现出更好的稳定性。在不同温度下分别测量其离子电导率发现,Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为1∶1时的电解质膜均高于纯PVDF-LiTFSI电解质膜和Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为2∶1和3∶1时的电解质膜。将其装配成电池后发现,0.1C下电池首次充放电比容量分别为90 m A·h/g和87 m A·h/g。以0.5C的电流循环25圈,放电比容量从57 mA·h/g衰减至51mA·h/g,容量保持率为99.7%。所以,以PVDF为基、Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为1∶1的固态电解质膜有优良的倍率性能和循环稳定性能。展开更多
基金This study was financially supported by the National Science Foundation of China(No.52201254)the National Science Foundation of Shandong Province(Nos.ZR2020MB090 and ZR2020QE012)+1 种基金the Project of“20 Items of University”of Jinan(No.202228046)Taishan Scholar Project of Shandong Province.
文摘Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) composite was easily synthesized via one-step succinct-operated hydrothermal process.The interconnected Co_(3)V_(2)O_(8)/Co_(3)O_(4) nanowires network can in-situ grow and anchor on the surface of Ti_(3)C_(2)T_(x) via the strong Co-F bonds and contribute tremendously to depress Ti_(3)C_(2)T_(x) self-restacking.Profiting from the synergistically interplayed effect among the multiple interfaces and high conductivity of Ti_(3)C_(2)T_(x) as well as outstanding stability of the as-designed nanostructure,the optimum Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x)electrode reaches a commendable specific capacitance(up to 3800 mF·cm^(−2)),great rate capability(80%capacitance retention after 20-times current increasing),and preeminent cycling stability(95.4%/85.5%retention at 7000th/20,000th cycle).Moreover,the all-solid-state asymmetric supercapacitor based on Co_(3)V_(2)O_(8)/Co_(3)O_(4)/Ti_(3)C_(2)T_(x) and active carbon can deliver a high energy density of 84.0μWh·cm^(−2) at the power energy of 3.2 mW·cm^(−2),and excellent cycling durability with 87.0%of initial capacitance retention upon 20,000 loops.This work provides a practicable pathway to tailor MXene-based composites for high-performance supercapacitor.
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the financial supporting by the National Natural Science Foundation of China(Grant Nos.21962009,22172071,22102069,22062013)the Natural Science Foundation of Jiangxi Province(Grant Nos.20202BAB203006,20181ACB20005)the Key Laboratory Foundation of Jiangxi Province for Environment and Energy Catalysis(Grant No.20181BCD40004).
文摘Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m^(-2),equaling to a weight percentage around 4.5%.It has been revealed that the quantities of surface active oxygen(O_(2)^(-))and acid sites are crucial for the reaction,which can adsorb and activate NO_(x)and NH_(3)reactants effectively.Below the monolayer dispersion threshold,Co_(3)O_(4)is finely dispersed as sub-monolayers or monolayers and in an amorphous state,which is favorable to generate the two kinds of active sites,hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide.However,the formation of crystalline Co_(3)O_(4)above the capacity is harmful to the reaction performance.4%Co_(3)O_(4)/ZSM-5,the catalyst close to the monolayer dispersion capacity,possesses the most abundant active O_(2)^(-)species and acidic sites,thereby demonstrating the best reaction performance in all the samples.It is proposed the optimal Co_(3)O_(4)/ZSM-5 catalyst can be prepared by loading the capacity amount of Co_(3)O_(4)onto HZSM-5 support.
基金the National Natural Science Foundation of China(Nos.21103024,61171008)Natural Science Foundation of Zhejiang Province(No.LY19B060006)+1 种基金National Key Research and Development Program of China(No.2018YFB1502900)Technology Development Project of Jiaxing University(No.70518047)。
文摘Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.
基金theNaturalScienceFoundationofHebeiProvince (No .2 96 16 9)
文摘The Li_(4+x)Al_xSi_(1-x)O_(4-y)Al_2O_3 (x = 0 to 0.5, y = 0 to 0.5) ionconductors were prepared by the Sol-Gel method and examined in detail. The powder and sinteredsamples were characterized by TG-DTA, XRD, SEM, and AC impedance techniques. The experimentalresults show that the conductivity and sinterability increase with the amount of excess Al_2O_3 inthe silicate. The particle size of the powder samples is about 0.13 μm. The maximum conductivity at18 ℃ is 3.057 * 10^(-5) s/cm for Li_(4.4)Al_(0.4)Si_(0.6)O_4-0.3 Al_2O_3.
文摘NASICON型快离子导体Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)(LATP)具有较高的离子电导率、较宽的电化学窗口及良好的水和空气稳定性,但其界面接触性能差。石榴石型Li_(7)La_(3)Zr_(2)O_(12)(LLZO)锂离子电导率高、电化学窗口较宽且热稳定性好,但其立方相结构不稳定,影响其实际应用。采用溶液浇筑法,制备纯PVDF-LiTFSI电解质膜和以PVDF为基、3种不同质量比的Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)的固态电解质膜,并探讨纯PVDF-LiTFSI电解质膜和3种不同质量比的活性无机电解质填料对复合固态电解质离子电导率的影响。结果表明,Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为1∶1时,电解质膜的XRD图谱的衍射峰比纯PVDF-LiTFSI下降更为明显,电化学窗口为3.9 V左右,表现出更好的稳定性。在不同温度下分别测量其离子电导率发现,Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为1∶1时的电解质膜均高于纯PVDF-LiTFSI电解质膜和Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为2∶1和3∶1时的电解质膜。将其装配成电池后发现,0.1C下电池首次充放电比容量分别为90 m A·h/g和87 m A·h/g。以0.5C的电流循环25圈,放电比容量从57 mA·h/g衰减至51mA·h/g,容量保持率为99.7%。所以,以PVDF为基、Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)和Li_(1+x)Al_(x)Ti_(2-x)(PO_(4))_(3)质量比为1∶1的固态电解质膜有优良的倍率性能和循环稳定性能。
