通过溶剂挥发诱导自组装和硫化、磷化处理合成具有多孔结构的CoS2和CoP催化剂,采用X-射线衍射、扫描电子显微镜等表征方法对材料的晶体结构和形貌进行分析。将这2种材料用于析氧反应的催化剂,结果表明,当电流密度达到10 m A/cm2时,2种...通过溶剂挥发诱导自组装和硫化、磷化处理合成具有多孔结构的CoS2和CoP催化剂,采用X-射线衍射、扫描电子显微镜等表征方法对材料的晶体结构和形貌进行分析。将这2种材料用于析氧反应的催化剂,结果表明,当电流密度达到10 m A/cm2时,2种催化剂均需要较小过电位。CoS2和CoP催化剂相应的塔菲尔曲线显示其斜率值较小,分别为78 m V/dec和77 m V/dec,说明这2种催化剂在析氧催化反应过程中表现出优异的催化性能和很好的析氧反应动力性能。展开更多
The construction of metal sulfides-carbon nanocomposites with a hollow structure is highly attractive for various energy storage and conversion technologies. Herein, we report a facile two-step method for preparing a ...The construction of metal sulfides-carbon nanocomposites with a hollow structure is highly attractive for various energy storage and conversion technologies. Herein, we report a facile two-step method for preparing a nanocomposite with CoS2 nanoparticles in N-doped carbon nanotube hollow frameworks （NCNTFs）. Starting from zeolitic imidazolate framework-67 （ZIF-67） particles, in situ reduced metallic cobalt nanocrystals expedite the formation of the hierarchical hollow frameworks from staggered carbon nanotubes via a carbonization process. After a follow-up sulfidation reaction with sulfur powder, the embedded cobalt crystals are transformed into CoS2 nanoparticles. Benefitting from the robust hollow frameworks made of N-doped carbon nanotubes and highly active CoS2 ultrafine nanoparticles, this advanced nanocomposite shows greatly enhanced lithium storage properties when evaluated as an electrode for lithium-ion batteries. Impressively, the resultant CoS2/NCNTF material delivers a high specific capacity of -937 mAh.g-1 at a current density of 1.0 A-g-1 with a cycle life longer than 160 cycles.展开更多
The facile synthesis of high-valued polymers from waste molecules or low-cost common chemicals presents a significant challenge.Here,we develop a series of degradable poly(thiocarbonate)s from the new step-growth poly...The facile synthesis of high-valued polymers from waste molecules or low-cost common chemicals presents a significant challenge.Here,we develop a series of degradable poly(thiocarbonate)s from the new step-growth polymerization of diols,carbonyl sulfide(CoS,or carbon disulfide,CS_(2)),and dichlorides.Diols and dichlorides are common chemicals,and CoS(CS_(2))is released as industrial waste.In addition to abun-dant feedstocks,the method is efficient and performed under mild conditions,using common organic bases as catalysts,and affording unprece-dented polymers.When cos,diols,and dihalides were used as monomers,optimized conditions could completely suppress the oxygen-sulfur exchange reaction,enabling the efficient synthesis of well-defined poly(monothiocarbonate)s with melting points ranging from 48°C to 101°C.These polymers,which have a structure similar to polyethylene with low-density in-chain polar groups,exhibit remarkable toughness and ductili-ty that rival those of high-density polyethylene(melting point:90°C,tensile strength:21.6±0.7 MPa,and elongation at break:576%).Moreover,the obtained poly(monothiocarbonate)s can be chemically degraded by alcoholysis to yield small-molecule diols and dithiols.When CS_(2)was used in place of cos,a pronounced oxygen-sulfur exchange reaction occurred.By optimizing reaction condition,it was found that polymers with-S(C=O)S-and-S(C=S)S-as the main repeating units exhibited high thermal stability and crystallinity.Thus,a new approach for regulat-ing the structure of polythiocarbonates via the oxygen-sulfur exchange reaction is developed.Overall,the polymers hold great potential for green materials due to their facile synthesis,readily available feedstocks,excellent performance,and chemical degradability.展开更多
以CoCl2·6H2O和CS(NH2)2为水热前驱物,在不同pH值下制备了CoS2粒子,对CoS2的物相组成、微观形貌、热稳定性和正极材料电化学性能进行表征和测试。结果表明,CoS2粒子在酸性和碱性溶液中形核生长机制不同,当pH=5和pH=10时分别获得黄...以CoCl2·6H2O和CS(NH2)2为水热前驱物,在不同pH值下制备了CoS2粒子,对CoS2的物相组成、微观形貌、热稳定性和正极材料电化学性能进行表征和测试。结果表明,CoS2粒子在酸性和碱性溶液中形核生长机制不同,当pH=5和pH=10时分别获得黄铁矿结构CoS2粒子其形貌为类球形和不规则块状,对应热分解温度为650℃和610℃。在100 m A/cm2放电时,两种形貌CoS2正极材料的电化学性能基本相近;800 m A/cm2放电时,类球形CoS2放电比容量较块状CoS2高9.65%,并具有优于后者的高初始放电电压及低内阻特性。展开更多
文摘通过溶剂挥发诱导自组装和硫化、磷化处理合成具有多孔结构的CoS2和CoP催化剂,采用X-射线衍射、扫描电子显微镜等表征方法对材料的晶体结构和形貌进行分析。将这2种材料用于析氧反应的催化剂,结果表明,当电流密度达到10 m A/cm2时,2种催化剂均需要较小过电位。CoS2和CoP催化剂相应的塔菲尔曲线显示其斜率值较小,分别为78 m V/dec和77 m V/dec,说明这2种催化剂在析氧催化反应过程中表现出优异的催化性能和很好的析氧反应动力性能。
文摘The construction of metal sulfides-carbon nanocomposites with a hollow structure is highly attractive for various energy storage and conversion technologies. Herein, we report a facile two-step method for preparing a nanocomposite with CoS2 nanoparticles in N-doped carbon nanotube hollow frameworks （NCNTFs）. Starting from zeolitic imidazolate framework-67 （ZIF-67） particles, in situ reduced metallic cobalt nanocrystals expedite the formation of the hierarchical hollow frameworks from staggered carbon nanotubes via a carbonization process. After a follow-up sulfidation reaction with sulfur powder, the embedded cobalt crystals are transformed into CoS2 nanoparticles. Benefitting from the robust hollow frameworks made of N-doped carbon nanotubes and highly active CoS2 ultrafine nanoparticles, this advanced nanocomposite shows greatly enhanced lithium storage properties when evaluated as an electrode for lithium-ion batteries. Impressively, the resultant CoS2/NCNTF material delivers a high specific capacity of -937 mAh.g-1 at a current density of 1.0 A-g-1 with a cycle life longer than 160 cycles.
基金supported by the National Natural Science Foundation of China(Nos.223B2119,U23A2083,52373014,52203129).
文摘The facile synthesis of high-valued polymers from waste molecules or low-cost common chemicals presents a significant challenge.Here,we develop a series of degradable poly(thiocarbonate)s from the new step-growth polymerization of diols,carbonyl sulfide(CoS,or carbon disulfide,CS_(2)),and dichlorides.Diols and dichlorides are common chemicals,and CoS(CS_(2))is released as industrial waste.In addition to abun-dant feedstocks,the method is efficient and performed under mild conditions,using common organic bases as catalysts,and affording unprece-dented polymers.When cos,diols,and dihalides were used as monomers,optimized conditions could completely suppress the oxygen-sulfur exchange reaction,enabling the efficient synthesis of well-defined poly(monothiocarbonate)s with melting points ranging from 48°C to 101°C.These polymers,which have a structure similar to polyethylene with low-density in-chain polar groups,exhibit remarkable toughness and ductili-ty that rival those of high-density polyethylene(melting point:90°C,tensile strength:21.6±0.7 MPa,and elongation at break:576%).Moreover,the obtained poly(monothiocarbonate)s can be chemically degraded by alcoholysis to yield small-molecule diols and dithiols.When CS_(2)was used in place of cos,a pronounced oxygen-sulfur exchange reaction occurred.By optimizing reaction condition,it was found that polymers with-S(C=O)S-and-S(C=S)S-as the main repeating units exhibited high thermal stability and crystallinity.Thus,a new approach for regulat-ing the structure of polythiocarbonates via the oxygen-sulfur exchange reaction is developed.Overall,the polymers hold great potential for green materials due to their facile synthesis,readily available feedstocks,excellent performance,and chemical degradability.
文摘以CoCl2·6H2O和CS(NH2)2为水热前驱物,在不同pH值下制备了CoS2粒子,对CoS2的物相组成、微观形貌、热稳定性和正极材料电化学性能进行表征和测试。结果表明,CoS2粒子在酸性和碱性溶液中形核生长机制不同,当pH=5和pH=10时分别获得黄铁矿结构CoS2粒子其形貌为类球形和不规则块状,对应热分解温度为650℃和610℃。在100 m A/cm2放电时,两种形貌CoS2正极材料的电化学性能基本相近;800 m A/cm2放电时,类球形CoS2放电比容量较块状CoS2高9.65%,并具有优于后者的高初始放电电压及低内阻特性。
