Cobalt-Aluminum layered double hydroxide(CoAl LDH) is a hopeful electrode material due to the advantage of easy modifiability for preparing LDH-based derivatives.However,there is short of modification methods to prepa...Cobalt-Aluminum layered double hydroxide(CoAl LDH) is a hopeful electrode material due to the advantage of easy modifiability for preparing LDH-based derivatives.However,there is short of modification methods to prepare the Co-based derivatives from CoAl LDH and also short of an intuitive perspective to analyze the pseudocapacitance mechanism of CoAl LDH and its derivatives.Herein,Graphene/CoAl LDH and its derivatives including Graphene/CoS,Graphene/CoS-1,Graphene/CoOOH,Graphene/CoP were prepared by reasonably using alkali etching treatment,sulfofication and phosphorization.The specific capacitance of Graphene/CoAl LDH,Graphene/CoS,Graphene/CoS-1,Graphene/CoOOH,Graphene/CoP at1 A g^(-1) are 260.7,371.3,440.8,61.4 and 122.2 F g^(-1),especially.The pseudocapacitance mechanism of Graphene/CoAl LDH and its derivatives was analyzed.Due to the positive effect of sulfofication on the electrical conductivity of GO and cobalt sulfide,the Graphene/CoS and Graphene/CoS-1 exhibit the optimal electrochemical performance and superior rate capability.In addition,due to the repulsion effect between Graphene and OH-,the Graphene/CoAl LDH exhibits optimal cycling stability of 224.1% capacitance retention after 20000 cycles.Besides,the reason of terrible specific capacitance of Graphene/CoOOH is that the presence of H bond in interlayer of CoOOH inhibits the interaction between Co3+ and OHspecies.Hence,not all modifications will increase the specific capacitance of the electrode materials.Overall,this work provides us with a detailed analysis of the electrochemical mechanism and correlation of CoAl LDH and its derivatives from the perspective of crystal structure and composition.展开更多
Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new funct...Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new functions will be significant for future science and technique development. In this work, alternatively stacked self-assembled CoAl LDH/MoS2 nanohybrid has been successfully synthesized by an exfoliation-flocculation method from positively charged CoAl LDH nanosheets（CoAl-NS） with negatively charged MoS2 nanosheets（MoS2-NS）. The CoAl LDH/MoS2 hybrid material exhibits an enhanced catalytic performance for oxygen evolution reaction（OER） compared with original constituents of CoAl LDH nanosheets and MoS2 nanosheets. The enhanced OER catalytic performance of CoAl LDH/MoS2 is demonstrated to be due to the improved electron transfer, more exposed catalytic active sites, and accelerated oxygen evolution reaction kinetics.展开更多
Metal–organic frameworks(MOFs)and layered double hydroxides(LDHs)have been considered to be one of the most promising and worthy hot spot materials to develop advanced catalysts for effi cient hydrogen evolution due ...Metal–organic frameworks(MOFs)and layered double hydroxides(LDHs)have been considered to be one of the most promising and worthy hot spot materials to develop advanced catalysts for effi cient hydrogen evolution due to their prominent characteristics,including unique structures,environmentally friendly nature,high redox activities,and homogeneously eff ective utilization of transition metal atoms.In this work,the delicate S-scheme heterojunction photocatalyst,CoAl LDH@Ni-MOF-74,was rationally designed and successfully constructed by coupling Ni-MOF-74 with CoAl LDH based on their peculiar structure,excellent electronic properties,and opposite surface potential for enhancing hydrogen generation activity under visible light irradiation.The CoAl LDH nanolayers evenly and dispersedly load on the surface of Ni-MOF-74.The CoAl LDH@Ni-MOF-74 exhibited higher photocatalytic hydrogen evolution activity compared with Ni-MOF-74 and CoAl LDH alone,mainly because the formation of the CoAl LDH@Ni-MOF-74 S-scheme heterojunction accelerated the recombination of several electrons(from conduction band(CB)of Ni-MOF-74)and holes(from valence band(VB)of CoAl LDH)and prevented the recombination of other electrons(from CB of CoAl LDH)and holes(from VB of Ni-MOF-74).展开更多
基金the financial support provided by the Graduate Research and innovation of Chongqing, China (Grant No. CYB18002)the National Natural Science Foundation of China (Grant No. 21576034 and 51908092)+1 种基金the State Education Ministry and Fundamental Research Funds for the Central Universities (2019CDQYCL042, 2019CDXYCL0031, 106112017CDJXSYY0001, 2018CDYJSY0055, 106112017CDJQJ138802, 106112017CDJSK04XK11, and 2018CDQYCL0027)the Joint Funds of the National Natural Science Foundation of China-Guangdong (Grant No. U1801254)。
文摘Cobalt-Aluminum layered double hydroxide(CoAl LDH) is a hopeful electrode material due to the advantage of easy modifiability for preparing LDH-based derivatives.However,there is short of modification methods to prepare the Co-based derivatives from CoAl LDH and also short of an intuitive perspective to analyze the pseudocapacitance mechanism of CoAl LDH and its derivatives.Herein,Graphene/CoAl LDH and its derivatives including Graphene/CoS,Graphene/CoS-1,Graphene/CoOOH,Graphene/CoP were prepared by reasonably using alkali etching treatment,sulfofication and phosphorization.The specific capacitance of Graphene/CoAl LDH,Graphene/CoS,Graphene/CoS-1,Graphene/CoOOH,Graphene/CoP at1 A g^(-1) are 260.7,371.3,440.8,61.4 and 122.2 F g^(-1),especially.The pseudocapacitance mechanism of Graphene/CoAl LDH and its derivatives was analyzed.Due to the positive effect of sulfofication on the electrical conductivity of GO and cobalt sulfide,the Graphene/CoS and Graphene/CoS-1 exhibit the optimal electrochemical performance and superior rate capability.In addition,due to the repulsion effect between Graphene and OH-,the Graphene/CoAl LDH exhibits optimal cycling stability of 224.1% capacitance retention after 20000 cycles.Besides,the reason of terrible specific capacitance of Graphene/CoOOH is that the presence of H bond in interlayer of CoOOH inhibits the interaction between Co3+ and OHspecies.Hence,not all modifications will increase the specific capacitance of the electrode materials.Overall,this work provides us with a detailed analysis of the electrochemical mechanism and correlation of CoAl LDH and its derivatives from the perspective of crystal structure and composition.
基金financially supported by NNSFC(No.21025104,21271171,and 91022018)
文摘Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new functions will be significant for future science and technique development. In this work, alternatively stacked self-assembled CoAl LDH/MoS2 nanohybrid has been successfully synthesized by an exfoliation-flocculation method from positively charged CoAl LDH nanosheets（CoAl-NS） with negatively charged MoS2 nanosheets（MoS2-NS）. The CoAl LDH/MoS2 hybrid material exhibits an enhanced catalytic performance for oxygen evolution reaction（OER） compared with original constituents of CoAl LDH nanosheets and MoS2 nanosheets. The enhanced OER catalytic performance of CoAl LDH/MoS2 is demonstrated to be due to the improved electron transfer, more exposed catalytic active sites, and accelerated oxygen evolution reaction kinetics.
基金This work was financially supported by the Natural Science Foundation of the Ningxia Hui Autonomous Region(No.2020AAC02026).
文摘Metal–organic frameworks(MOFs)and layered double hydroxides(LDHs)have been considered to be one of the most promising and worthy hot spot materials to develop advanced catalysts for effi cient hydrogen evolution due to their prominent characteristics,including unique structures,environmentally friendly nature,high redox activities,and homogeneously eff ective utilization of transition metal atoms.In this work,the delicate S-scheme heterojunction photocatalyst,CoAl LDH@Ni-MOF-74,was rationally designed and successfully constructed by coupling Ni-MOF-74 with CoAl LDH based on their peculiar structure,excellent electronic properties,and opposite surface potential for enhancing hydrogen generation activity under visible light irradiation.The CoAl LDH nanolayers evenly and dispersedly load on the surface of Ni-MOF-74.The CoAl LDH@Ni-MOF-74 exhibited higher photocatalytic hydrogen evolution activity compared with Ni-MOF-74 and CoAl LDH alone,mainly because the formation of the CoAl LDH@Ni-MOF-74 S-scheme heterojunction accelerated the recombination of several electrons(from conduction band(CB)of Ni-MOF-74)and holes(from valence band(VB)of CoAl LDH)and prevented the recombination of other electrons(from CB of CoAl LDH)and holes(from VB of Ni-MOF-74).
