Carbon nitride(CN_x) films supported on fluorine-doped tin oxide(FTO) glass are prepared by radio frequency magnetron sputtering, in which the film thicknesses are 90-100 nm, and the element components in the CNX film...Carbon nitride(CN_x) films supported on fluorine-doped tin oxide(FTO) glass are prepared by radio frequency magnetron sputtering, in which the film thicknesses are 90-100 nm, and the element components in the CNX films are in the range of x = 0.15-0.25. The as-prepared CN_x is for the first time used as counter electrode for dye-sensitized solar cells(DSSCs), and show a preparation-temperature dependent electrochemical performance. X-ray photoelectron spectroscopy(XPS) demonstrates that there is a higher proportion of sp^2 C=C and sp^3 C-N hybridized bonds in CN_x-500(the sample treated at 500 ℃) than in CNX-RT(the sample without a heat treatment). It is proposed that the sp^2 C=C and sp^3 C-N hybridized bonds in the CN_x films are helpful for improving the electrocatalytic activities in DSSCs. Meanwhile, Raman spectra also prove that CN_x-500 has a relatively high graphitization level that means an increasing electrical conductivity. This further explains why the sample after the heat treatment has a higher electrochemical performance in DSSCs. In addition, the as-prepared CN_x counter electrodes have a good light transmittance in the visible light region. The results are meaningful for developing low-cost metal-free transparent counter electrodes for DSSCs.展开更多
In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode mater...In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4 GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4 GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4 GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4 GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.展开更多
Molybdenum selenide is a potential alternative to counter electrode of a platinum-free dye-sensitized solar cell(DSSC). In this work, an in situ magnetron sputtering method is developed to prepare MoSe2 electrodes. Th...Molybdenum selenide is a potential alternative to counter electrode of a platinum-free dye-sensitized solar cell(DSSC). In this work, an in situ magnetron sputtering method is developed to prepare MoSe2 electrodes. The MoSe2 electrodes obtained at various temperatures from 300 and 550 ℃ are used as counter electrode for a dye-sensitized solar cell. Photovoltaic measurement results indicate that the MoSe2 electrodes prepared at 400 ℃ has the optimized performance, and the corresponding DSSCs provide an energy conversion efficiency of 6.83% which is comparable than that of the reference DSSC with platinum as counter electrode(6.51%). With further increasing the preparation temperature of the MoSe2 electrodes, the corresponding DSSCs decrease gradually to 5.96% for 550 ℃. Electrochemical impedance spectra(EIS) reveal that charge transfer resistance(Rct) of MoSe2 electrodes is rising with increase of the temperature from 400 to 500 ℃, suggesting a downward electrocatalytic activity. Though the MoSe2 electrode prepared at 550 ℃ show a reduced Rct, its series resistance(Rs) and diffusion resistance(Zw) increase obviously. Considering that MoSe2 phase cannot be formed at 300 ℃, it can be concluded that the prepared temperature as low as possible is favored for its final electrochemical performance. The results are very significant for developing low-cost and responsible counter electrodes for dye-sensitized solar cells.展开更多
Using simple methods to obtain efficient catalysts has been a long-standing goal for researchers.In this work,the employment of a one-pot pyrolysis reaction to achieve molecular confinement,has led to the preparation ...Using simple methods to obtain efficient catalysts has been a long-standing goal for researchers.In this work,the employment of a one-pot pyrolysis reaction to achieve molecular confinement,has led to the preparation of ruthenium(Ru)-based nanoclusters in a carbon matrix.A unique feature of the synthetic approach employed is that solvent and substrates were calcined together.As solvent evaporates,during calcination,the substrates form a dense solid which has the effect of limiting the aggregation of Ru centers during the carbonization process.The catalyst prepared in this simple manner showed an impressively high activity with respect to the hydrogen/oxygen evolution reaction(HER/OER).The Ru nanoclusters(Ru NCs),as the hydrogen evolution reaction(HER)catalysts,require ultralow overpotentials of 5 mV and 5.1 mV at-10 mA·cm^(-2) in 1.0 M KOH,and 0.5 M H_(2)SO_(4),respectively.Furthermore,the catalyst prepared by the one-pot method has higher crystallinity,a higher Ru content and an ultrafine cluster size,which contributes to its exceptional electrochemical performance.Meanwhile,the RuO_(x) nanoclusters(RuO_(x) NCs),obtained by oxidizing the aforementioned Ru NCs,exhibited good oxygen evolution reaction(OER)performance with an overpotential of 266 mV at 10 mA·cm^(-2).When applied to overall water splitting,Ru/RuO_(x) nanoclusters as the cathode and anode catalysts can reach 10 mA·cm^(-2) at cell voltages of only 1.49 V in 1 M KOH.展开更多
Monodisperse Pt nanoparticles(NPs) were prepared by reduction of platinum acetylacetonate in octadecene with the presence of Fe(CO)5. The synthesized nanocatalysts presented high activity and selectively for hydrogena...Monodisperse Pt nanoparticles(NPs) were prepared by reduction of platinum acetylacetonate in octadecene with the presence of Fe(CO)5. The synthesized nanocatalysts presented high activity and selectively for hydrogenation of ortho-halogenated nitrobenzene to the corresponding ortho-halogenated aniline under mild reaction conditions.展开更多
Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert-butylhydroperoxide(TBHP) as the oxidant. Influence...Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert-butylhydroperoxide(TBHP) as the oxidant. Influence of factors, such as the catalyst, solvents, and the reaction temperature, were studied to determine the optimal reaction conditions. In addition, we explored the substrate generality and observed excellent yields.展开更多
基金Financial support from the 973 Program (2015CB251100)NSFC (51001063)MOE Innovation Team (IRT13022)
文摘Carbon nitride(CN_x) films supported on fluorine-doped tin oxide(FTO) glass are prepared by radio frequency magnetron sputtering, in which the film thicknesses are 90-100 nm, and the element components in the CNX films are in the range of x = 0.15-0.25. The as-prepared CN_x is for the first time used as counter electrode for dye-sensitized solar cells(DSSCs), and show a preparation-temperature dependent electrochemical performance. X-ray photoelectron spectroscopy(XPS) demonstrates that there is a higher proportion of sp^2 C=C and sp^3 C-N hybridized bonds in CN_x-500(the sample treated at 500 ℃) than in CNX-RT(the sample without a heat treatment). It is proposed that the sp^2 C=C and sp^3 C-N hybridized bonds in the CN_x films are helpful for improving the electrocatalytic activities in DSSCs. Meanwhile, Raman spectra also prove that CN_x-500 has a relatively high graphitization level that means an increasing electrical conductivity. This further explains why the sample after the heat treatment has a higher electrochemical performance in DSSCs. In addition, the as-prepared CN_x counter electrodes have a good light transmittance in the visible light region. The results are meaningful for developing low-cost metal-free transparent counter electrodes for DSSCs.
基金financial support from National Natural Science Foundation of China (No. 21373006 and No. 51801030)the Science and Technology Program of Suzhou (SYG201732)+4 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the project of Scientific and Technologic Infrastructure of Suzhou (SZS201708)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (17KJB430029)One-hundred Young Talents (Class A) of Guangdong University of Technology (No. 220413198)Natural Science Foundation of Guangdong Providence (No. 2018A030310571)
文摘In this manuscript, we have demonstrated the delicate design and synthesis of bimetallic oxides nanoparticles derived from metal–oleate complex embedded in 3D graphene networks(MnO/CoMn_2O_4 GN), as an anode material for lithium ion batteries. The novel synthesis of the MnO/CoMn_2O_4 GN consists of thermal decomposition of metal–oleate complex containing cobalt and manganese metals and oleate ligand, forming bimetallic oxides nanoparticles, followed by a selfassembly route with reduced graphene oxides. The MnO/CoMn_2O_4 GN composite, with a unique architecture of bimetallic oxides nanoparticles encapsulated in 3D graphene networks, rationally integrates several benefits including shortening the di usion path of Li^+ ions, improving electrical conductivity and mitigating volume variation during cycling. Studies show that the electrochemical reaction processes of MnO/Co Mn_2O_4 GN electrodes are dominated by the pseudocapacitive behavior, leading to fast Li^+ charge/discharge reactions. As a result, the MnO/CoMn_2O_4 GN manifests high initial specific capacity, stable cycling performance, and excellent rate capability.
基金supported by the National Basic Research Program(973 Program,2015CB251100)Natural Science Foundation of Tianjin(18JCZDJC31000)~~
文摘Molybdenum selenide is a potential alternative to counter electrode of a platinum-free dye-sensitized solar cell(DSSC). In this work, an in situ magnetron sputtering method is developed to prepare MoSe2 electrodes. The MoSe2 electrodes obtained at various temperatures from 300 and 550 ℃ are used as counter electrode for a dye-sensitized solar cell. Photovoltaic measurement results indicate that the MoSe2 electrodes prepared at 400 ℃ has the optimized performance, and the corresponding DSSCs provide an energy conversion efficiency of 6.83% which is comparable than that of the reference DSSC with platinum as counter electrode(6.51%). With further increasing the preparation temperature of the MoSe2 electrodes, the corresponding DSSCs decrease gradually to 5.96% for 550 ℃. Electrochemical impedance spectra(EIS) reveal that charge transfer resistance(Rct) of MoSe2 electrodes is rising with increase of the temperature from 400 to 500 ℃, suggesting a downward electrocatalytic activity. Though the MoSe2 electrode prepared at 550 ℃ show a reduced Rct, its series resistance(Rs) and diffusion resistance(Zw) increase obviously. Considering that MoSe2 phase cannot be formed at 300 ℃, it can be concluded that the prepared temperature as low as possible is favored for its final electrochemical performance. The results are very significant for developing low-cost and responsible counter electrodes for dye-sensitized solar cells.
基金support from the National Natural Science Foundation of China(Nos.21531006 and 21773163)Collaborative Innovation Center of Suzhou Nano Science and Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201905)the Research Fund Program of Key Laboratory of Rare Mineral,MNR(No.KLRM-KF202004).
文摘Using simple methods to obtain efficient catalysts has been a long-standing goal for researchers.In this work,the employment of a one-pot pyrolysis reaction to achieve molecular confinement,has led to the preparation of ruthenium(Ru)-based nanoclusters in a carbon matrix.A unique feature of the synthetic approach employed is that solvent and substrates were calcined together.As solvent evaporates,during calcination,the substrates form a dense solid which has the effect of limiting the aggregation of Ru centers during the carbonization process.The catalyst prepared in this simple manner showed an impressively high activity with respect to the hydrogen/oxygen evolution reaction(HER/OER).The Ru nanoclusters(Ru NCs),as the hydrogen evolution reaction(HER)catalysts,require ultralow overpotentials of 5 mV and 5.1 mV at-10 mA·cm^(-2) in 1.0 M KOH,and 0.5 M H_(2)SO_(4),respectively.Furthermore,the catalyst prepared by the one-pot method has higher crystallinity,a higher Ru content and an ultrafine cluster size,which contributes to its exceptional electrochemical performance.Meanwhile,the RuO_(x) nanoclusters(RuO_(x) NCs),obtained by oxidizing the aforementioned Ru NCs,exhibited good oxygen evolution reaction(OER)performance with an overpotential of 266 mV at 10 mA·cm^(-2).When applied to overall water splitting,Ru/RuO_(x) nanoclusters as the cathode and anode catalysts can reach 10 mA·cm^(-2) at cell voltages of only 1.49 V in 1 M KOH.
基金financially supported by the National Natural Science Foundation of China(21373006,51402203)the Natural Science Foundation of Jiangsu Province for Young Scholars(BK20140326)+1 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions(14KJB430021)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Monodisperse Pt nanoparticles(NPs) were prepared by reduction of platinum acetylacetonate in octadecene with the presence of Fe(CO)5. The synthesized nanocatalysts presented high activity and selectively for hydrogenation of ortho-halogenated nitrobenzene to the corresponding ortho-halogenated aniline under mild reaction conditions.
基金supported by the National Natural Science Foundation of China (21373006, 51402203)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert-butylhydroperoxide(TBHP) as the oxidant. Influence of factors, such as the catalyst, solvents, and the reaction temperature, were studied to determine the optimal reaction conditions. In addition, we explored the substrate generality and observed excellent yields.
