WO3 photocatalyst decorated with highly dispersed CoWO4 or CuWO4 nanoparticles(CoWO4/WO3 or CuWO4/WO3) was successfully synthesized using an in-situ impregnation method followed by solid-state reaction. The structure,...WO3 photocatalyst decorated with highly dispersed CoWO4 or CuWO4 nanoparticles(CoWO4/WO3 or CuWO4/WO3) was successfully synthesized using an in-situ impregnation method followed by solid-state reaction. The structure, morphology, photophysical property, and photocatalytic degradation mechanism of the CoWO4/WO3 or CuWO4/WO3 samples were investigated by XRD, SEM, TEM, EDS, HR-TEM, UV-vis DRS, SPV, and active trapping techniques. The XRD, SEM, and TEM results have revealed that CoWO4 or CuWO4 are highly dispersed on the WO3 surface, when the loading amount of CoWO4 or CuWO4 is small. However, obvious agglomeration is observed for the CoWO4 or CuWO4 particles, when the loading amount of CoWO4 or CuWO4 was increased. The visible-light photocatalytic degradation of RhB shows that all CoWO4/WO3 or CuWO4/WO3 samples exhibit superior photocatalytic performance as compared to pure WO3. This is mainly attributed to the formation of type II heterojunction between WO3 and CoWO4 or CuWO4, which can promote the photogenerated electrons and holes separation and transfer. Moreover, it is found that 0.2% CoWO4/WO3 or 0.2% CuWO4/WO3, in which MWO4 nanoparticles are uniformly dispersed on the surface of WO3, can achieve the most excellent photocatalytic activity among CoWO4/WO3 or CuWO4/WO3 samples, respectively. As compared with WO3, an enhancement about 9.1 times or 6.8 times in photocatalytic activity is observed on 0.2% CoWO4/WO3 or 0.2% CuWO4/WO3, respectively. Furthermore, the active species trapping experiment demonstrates that ·OH, h+, and ·O-2 generated during the photocatalytic process are all the reactive species in photocatalytic degradation of Rhodamine B(RhB) on CoWO4/WO3 or CuWO4/WO3. This study presents a strategy to design superior photocatalyst for organic compound degradation.展开更多
Transition-metal oxides have attracted increased attention in the application of high-performance lithium ion batteries（LIBs）, owing to its higher reversible capacity,better structural stability and high electronic ...Transition-metal oxides have attracted increased attention in the application of high-performance lithium ion batteries（LIBs）, owing to its higher reversible capacity,better structural stability and high electronic conductivity.Herein, CoWO4 nanoparticles wrapped by reduced graphene oxide（CoWO4–RGO） were synthesized via a facile hydrothermal route followed by a subsequent heat-treatment process. When evaluated as the anode of LIB, the synthetic CoWO4–RGO nanocomposite exhibits better Li^＋ storage properties than pure CoWO4 nanostructures synthesized without graphene oxide（GO）. Specifically, it delivers a high initial specific discharge capacity of1100 mAh·g^-1 at a current density of 100 mA·g^-1, and a good reversible performance of 567 mAh·g^-1 remains after the 100th cycle. Moreover, full battery using CoWO4–RGO as anode and commercial LiCoO2 powder as cathode was assembled, which can be sufficient to turn on a 3 V,10 mW blue light emitting diode（LED）. The enhanced electrochemical performance for lithium storage can be attributed to the three-dimensional（3D） structure of the CoWO4–RGO nanocomposite, which can accommodate huge volume changes, and synergetic effect between CoWO4 and reduced graphite oxide（RGO） nanosheets,including an increased conductivity, shortened Li^＋ diffusion path.展开更多
基金supported financially by the National Natural Science Foundation of China(21573101)the Program for Liaoning Excellent Talents in University(LR2017011)+1 种基金the support plan for Distinguished Professor of Liaoning Province([2015]153)the Liaoning BaiQianWan Talents program([2017]96)
文摘WO3 photocatalyst decorated with highly dispersed CoWO4 or CuWO4 nanoparticles(CoWO4/WO3 or CuWO4/WO3) was successfully synthesized using an in-situ impregnation method followed by solid-state reaction. The structure, morphology, photophysical property, and photocatalytic degradation mechanism of the CoWO4/WO3 or CuWO4/WO3 samples were investigated by XRD, SEM, TEM, EDS, HR-TEM, UV-vis DRS, SPV, and active trapping techniques. The XRD, SEM, and TEM results have revealed that CoWO4 or CuWO4 are highly dispersed on the WO3 surface, when the loading amount of CoWO4 or CuWO4 is small. However, obvious agglomeration is observed for the CoWO4 or CuWO4 particles, when the loading amount of CoWO4 or CuWO4 was increased. The visible-light photocatalytic degradation of RhB shows that all CoWO4/WO3 or CuWO4/WO3 samples exhibit superior photocatalytic performance as compared to pure WO3. This is mainly attributed to the formation of type II heterojunction between WO3 and CoWO4 or CuWO4, which can promote the photogenerated electrons and holes separation and transfer. Moreover, it is found that 0.2% CoWO4/WO3 or 0.2% CuWO4/WO3, in which MWO4 nanoparticles are uniformly dispersed on the surface of WO3, can achieve the most excellent photocatalytic activity among CoWO4/WO3 or CuWO4/WO3 samples, respectively. As compared with WO3, an enhancement about 9.1 times or 6.8 times in photocatalytic activity is observed on 0.2% CoWO4/WO3 or 0.2% CuWO4/WO3, respectively. Furthermore, the active species trapping experiment demonstrates that ·OH, h+, and ·O-2 generated during the photocatalytic process are all the reactive species in photocatalytic degradation of Rhodamine B(RhB) on CoWO4/WO3 or CuWO4/WO3. This study presents a strategy to design superior photocatalyst for organic compound degradation.
基金financially supported by the National Natural Science Foundation of China(Nos.21631004,21371053,21401048 and 21173072)the International Science and Technology Cooperation Program of China(No.2014DFR41110)+1 种基金the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2016016)the Harbin Science and Technology Innovation Talents Research Foundation(No.2015RAQXJ057)
文摘Transition-metal oxides have attracted increased attention in the application of high-performance lithium ion batteries（LIBs）, owing to its higher reversible capacity,better structural stability and high electronic conductivity.Herein, CoWO4 nanoparticles wrapped by reduced graphene oxide（CoWO4–RGO） were synthesized via a facile hydrothermal route followed by a subsequent heat-treatment process. When evaluated as the anode of LIB, the synthetic CoWO4–RGO nanocomposite exhibits better Li^＋ storage properties than pure CoWO4 nanostructures synthesized without graphene oxide（GO）. Specifically, it delivers a high initial specific discharge capacity of1100 mAh·g^-1 at a current density of 100 mA·g^-1, and a good reversible performance of 567 mAh·g^-1 remains after the 100th cycle. Moreover, full battery using CoWO4–RGO as anode and commercial LiCoO2 powder as cathode was assembled, which can be sufficient to turn on a 3 V,10 mW blue light emitting diode（LED）. The enhanced electrochemical performance for lithium storage can be attributed to the three-dimensional（3D） structure of the CoWO4–RGO nanocomposite, which can accommodate huge volume changes, and synergetic effect between CoWO4 and reduced graphite oxide（RGO） nanosheets,including an increased conductivity, shortened Li^＋ diffusion path.
