Water electrolysis is considered to be an effective way to fabricate hydrogen, and it is desirable to find the highly efficient, inexpensive and good durability bifunctional electrocatalysts for overall water splittin...Water electrolysis is considered to be an effective way to fabricate hydrogen, and it is desirable to find the highly efficient, inexpensive and good durability bifunctional electrocatalysts for overall water splitting.In this paper, we synthesis a unique structured catalyst that was composed by Co_9S_8 nanowires and nickel cobalt layered double hydroxide(NiCo-LDH) nanosheets. The ultrathin nanosheets decorated on the Co_9S_8 nanoarrays offer large specific surface area, numerous active edge sites and excellent electrical conductivity for fast electron transfer. Benefiting from this heterogeneous structure, the catalyst presents excellent catalytic performance in alkaline media. It requires 168 mV to reach current density of 10 mA/cm^2 for HER and 278 m V to reach current density of 30 mA/cm^2 for OER. When used as electrode in a homemade two-electrode system, it only needs t a voltage of 1.63 V to achieve current densities of 10 mA/cm^2, which proves Co_9S_8@NiCo LDH/NF as a superior bifunctional catalyst for water splitting.展开更多
以四水合钼酸铵、六水合硝酸钴和硫脲为原料,采用一步水热法在钛网(TM)上原位构筑了不同阵列结构Co_(9)S_(8)/MoS_(2)@TM催化电极。通过改变原料中钴、钼、硫的物质的量之比来调控Co_(9)S_(8)/MoS_(2)@TM电极的结构。采用SEM、XRD和XPS...以四水合钼酸铵、六水合硝酸钴和硫脲为原料,采用一步水热法在钛网(TM)上原位构筑了不同阵列结构Co_(9)S_(8)/MoS_(2)@TM催化电极。通过改变原料中钴、钼、硫的物质的量之比来调控Co_(9)S_(8)/MoS_(2)@TM电极的结构。采用SEM、XRD和XPS对Co_(9)S_(8)/MoS_(2)@TM进行物相分析和形貌表征,并在1 mol/L KOH电解液中对Co_(9)S_(8)/MoS_(2)@TM的电催化析氧性能进行了研究。结果表明,钴、钼、硫的物质的量之比为10∶14∶600时,制备的Co_(9)S_(8)/MoS_(2)@TM为3D花瓣状阵列结构,且在10 m A/cm^(2)电流密度下过电势为271 m V,塔菲尔斜率为88.5 m V/dec,具有良好的析氧稳定性和耐久性,展现了优异的电化学性能。展开更多
Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered struct...Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered structure and can be used in the field of photocatalytic water splitting.Therefore,herein,new progress in the preparation of graphene using Cu I powder as a catalytic material and the combination of a facile hydrothermal method to prepare a new composite material,Co_(9)S_(8)-GDY-Cu I,is reported.The hydrogen production activity of Co9S8-GDY-Cu I in the sensitization system reached 1411.82μmol g^(-1) h^(-1),which is 10.29 times that of pure GDY.A series of characterization techniques were used to provide evidence for the successful preparation of the material and its superior photocatalytic activity.Raman spectroscopy showed that the material contains acetylenic bonds,and the X-ray photoelectron spectroscopy carbon fitting peaks indicated the presence of C-C(sp^(2))and C-C(sp),further demonstrating that GDY was successfully prepared.A possible reaction mechanism was proposed by making use of UV-visible diffuse reflectance and Mott-Schottky analyses.The results showed that a double S-scheme heterojunction was constructed between the samples,which effectively accelerated the separation and transfer of electrons.In addition,the introduction of Co9S8 nanoparticles greatly improved the visible light absorption capacity of Co_(9)S_(8)-GDY-Cu I.Photoluminescence spectroscopy and related electrochemical characterization further proved that recombination of the electron-hole pairs in the composite material was effectively suppressed.展开更多
Tailoring valence electron delocalization of transition metal center is of importance to achieve highly-active electrocatalysts for oxygen evolution reaction(OER).Herein,we demonstrate a“poor sulfur”route to synthes...Tailoring valence electron delocalization of transition metal center is of importance to achieve highly-active electrocatalysts for oxygen evolution reaction(OER).Herein,we demonstrate a“poor sulfur”route to synthesize surface electron-deficient Co_(9)S_(8) nanoarrays,where the binding energy(BE)of Co metal center is considerably higher than all reported Co_(9)S_(8)-based electrocatalysts.The resulting Co_(9)S_(8) electrocatalysts only require the overpotentials(h)of 265 and 326 mV at 10 and 100 mA cm^(-2) with a low Tafel slope of 56 mV dec^-(1) and a 60 hlasting stability in alkaline media.The OER kinetics are greatly expedited with a low reaction activation energy of 27.9 kJ mol^-(1) as well as abundant OOH*key intermediates(24%),thus exhibiting excellent catalytic performances.The surface electron-deficient engineering gives an available strategy to improve the catalytic activity of other advanced non-noble electrocatalysts.展开更多
钠离子电池(SIBs)的阳极材料一直备受研究关注,但缓慢的动力学行为和较大的体积变化限制了其在实际应用中的推广。为了克服这些问题,本研究利用金属有机框架和MoS_(2)的优异性能,设计并制备了具有稳定骨架结构的复合材料。以Co-ZIF为前...钠离子电池(SIBs)的阳极材料一直备受研究关注,但缓慢的动力学行为和较大的体积变化限制了其在实际应用中的推广。为了克服这些问题,本研究利用金属有机框架和MoS_(2)的优异性能,设计并制备了具有稳定骨架结构的复合材料。以Co-ZIF为前驱体,添加Mo源材料,在高温硫化烧结的过程中,构建了花状的Co_(9)S_(8)/MoS_(2)/C复合材料,探究其在不同温度条件下的结构和电化学性能。此外,通过密度泛函理论(DFT)分析了Co9S8(001)/MoS2异质结对扩散动力学的影响。结果表明,电子结构在异质结构的界面处发生了重塑,Co_(9)S_(8)/MoS_(2)表现出典型的金属性和显著增强的电子导电性。在所有样品中,700℃合成的阳极材料Co_(9)S_(8)/MoS_(2)/C具有更稳定的结构和优异的电化学性能。当电流密度从4000恢复到40 mA g^(-1)时,Co_(9)S_(8)/MoS_(2)/C-700的放电容量可以从368 mAh g^(-1)完全恢复到571 mAh g^(-1),并稳定在543 mAh g^(-1)。综上所述,本研究提供了一些关于异质结材料合理制备的思路,有助于设计高性能的金属钠离子电池负极复合材料。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
基金supported by the National Natural Science Foundation of China (21571012)
文摘Water electrolysis is considered to be an effective way to fabricate hydrogen, and it is desirable to find the highly efficient, inexpensive and good durability bifunctional electrocatalysts for overall water splitting.In this paper, we synthesis a unique structured catalyst that was composed by Co_9S_8 nanowires and nickel cobalt layered double hydroxide(NiCo-LDH) nanosheets. The ultrathin nanosheets decorated on the Co_9S_8 nanoarrays offer large specific surface area, numerous active edge sites and excellent electrical conductivity for fast electron transfer. Benefiting from this heterogeneous structure, the catalyst presents excellent catalytic performance in alkaline media. It requires 168 mV to reach current density of 10 mA/cm^2 for HER and 278 m V to reach current density of 30 mA/cm^2 for OER. When used as electrode in a homemade two-electrode system, it only needs t a voltage of 1.63 V to achieve current densities of 10 mA/cm^2, which proves Co_9S_8@NiCo LDH/NF as a superior bifunctional catalyst for water splitting.
文摘以四水合钼酸铵、六水合硝酸钴和硫脲为原料,采用一步水热法在钛网(TM)上原位构筑了不同阵列结构Co_(9)S_(8)/MoS_(2)@TM催化电极。通过改变原料中钴、钼、硫的物质的量之比来调控Co_(9)S_(8)/MoS_(2)@TM电极的结构。采用SEM、XRD和XPS对Co_(9)S_(8)/MoS_(2)@TM进行物相分析和形貌表征,并在1 mol/L KOH电解液中对Co_(9)S_(8)/MoS_(2)@TM的电催化析氧性能进行了研究。结果表明,钴、钼、硫的物质的量之比为10∶14∶600时,制备的Co_(9)S_(8)/MoS_(2)@TM为3D花瓣状阵列结构,且在10 m A/cm^(2)电流密度下过电势为271 m V,塔菲尔斜率为88.5 m V/dec,具有良好的析氧稳定性和耐久性,展现了优异的电化学性能。
文摘Graphdiyne(GDY,g-C_(n)H_(2n-2)),a novel two-dimensional carbon hybrid material,has attracted significant attention owing to its unique and excellent properties.As a new type of carbon material,GDY has a layered structure and can be used in the field of photocatalytic water splitting.Therefore,herein,new progress in the preparation of graphene using Cu I powder as a catalytic material and the combination of a facile hydrothermal method to prepare a new composite material,Co_(9)S_(8)-GDY-Cu I,is reported.The hydrogen production activity of Co9S8-GDY-Cu I in the sensitization system reached 1411.82μmol g^(-1) h^(-1),which is 10.29 times that of pure GDY.A series of characterization techniques were used to provide evidence for the successful preparation of the material and its superior photocatalytic activity.Raman spectroscopy showed that the material contains acetylenic bonds,and the X-ray photoelectron spectroscopy carbon fitting peaks indicated the presence of C-C(sp^(2))and C-C(sp),further demonstrating that GDY was successfully prepared.A possible reaction mechanism was proposed by making use of UV-visible diffuse reflectance and Mott-Schottky analyses.The results showed that a double S-scheme heterojunction was constructed between the samples,which effectively accelerated the separation and transfer of electrons.In addition,the introduction of Co9S8 nanoparticles greatly improved the visible light absorption capacity of Co_(9)S_(8)-GDY-Cu I.Photoluminescence spectroscopy and related electrochemical characterization further proved that recombination of the electron-hole pairs in the composite material was effectively suppressed.
基金supported by the National Natural Science Foundation of China(21838003,21808061 and 91534122)the Social Development Program of Shanghai(17DZ1200900)+1 种基金the Shanghai Scientific and Technological Innovation Project(18JC1410600)he Fundamental Research Funds for the Central Universities(222201718002).
文摘Tailoring valence electron delocalization of transition metal center is of importance to achieve highly-active electrocatalysts for oxygen evolution reaction(OER).Herein,we demonstrate a“poor sulfur”route to synthesize surface electron-deficient Co_(9)S_(8) nanoarrays,where the binding energy(BE)of Co metal center is considerably higher than all reported Co_(9)S_(8)-based electrocatalysts.The resulting Co_(9)S_(8) electrocatalysts only require the overpotentials(h)of 265 and 326 mV at 10 and 100 mA cm^(-2) with a low Tafel slope of 56 mV dec^-(1) and a 60 hlasting stability in alkaline media.The OER kinetics are greatly expedited with a low reaction activation energy of 27.9 kJ mol^-(1) as well as abundant OOH*key intermediates(24%),thus exhibiting excellent catalytic performances.The surface electron-deficient engineering gives an available strategy to improve the catalytic activity of other advanced non-noble electrocatalysts.
文摘钠离子电池(SIBs)的阳极材料一直备受研究关注,但缓慢的动力学行为和较大的体积变化限制了其在实际应用中的推广。为了克服这些问题,本研究利用金属有机框架和MoS_(2)的优异性能,设计并制备了具有稳定骨架结构的复合材料。以Co-ZIF为前驱体,添加Mo源材料,在高温硫化烧结的过程中,构建了花状的Co_(9)S_(8)/MoS_(2)/C复合材料,探究其在不同温度条件下的结构和电化学性能。此外,通过密度泛函理论(DFT)分析了Co9S8(001)/MoS2异质结对扩散动力学的影响。结果表明,电子结构在异质结构的界面处发生了重塑,Co_(9)S_(8)/MoS_(2)表现出典型的金属性和显著增强的电子导电性。在所有样品中,700℃合成的阳极材料Co_(9)S_(8)/MoS_(2)/C具有更稳定的结构和优异的电化学性能。当电流密度从4000恢复到40 mA g^(-1)时,Co_(9)S_(8)/MoS_(2)/C-700的放电容量可以从368 mAh g^(-1)完全恢复到571 mAh g^(-1),并稳定在543 mAh g^(-1)。综上所述,本研究提供了一些关于异质结材料合理制备的思路,有助于设计高性能的金属钠离子电池负极复合材料。
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.
