A large number of surplus glycerol from the biodiesel production can be used as renewable feedstock to produce glycerol carbonate. In this paper, a series of guanidine-based ionic liquids were synthesized to catalyze ...A large number of surplus glycerol from the biodiesel production can be used as renewable feedstock to produce glycerol carbonate. In this paper, a series of guanidine-based ionic liquids were synthesized to catalyze the transesterification of glycerol and dimethyl carbonate. The tunable basicity and the anion–cation cooperative effect were responsible for the obtained results. The [TMG][TFE] showed the best activity turnover frequency(TOF)of 1754.0 h^(-1), glycerol(GL) conversion of 91.8%, glycerol carbonate(GC) selectivity of 95.5%) at 80 °C with 0.1 mol% catalyst for 30 min. The reaction mechanism of the transesterification was also proposed.展开更多
To maximize the size and structural advantages of nanomaterials in electrooxidation of ethanol, we herein report the synthesis of core–shell gold(Au)@Palladium(Pd) nanoparticles smaller than 3 nm in an ionic liquid, ...To maximize the size and structural advantages of nanomaterials in electrooxidation of ethanol, we herein report the synthesis of core–shell gold(Au)@Palladium(Pd) nanoparticles smaller than 3 nm in an ionic liquid, which combines the advantages of ionic liquids in preparing fine metal nanoparticles with the benefits of core–shell nanostructures. This synthetic strategy relies on the use of an ionic liquid(1-(2'-aminoethyl)-3-methyl-imidazolum tetrafluoroborate) as a stabilizer to produce Au particles with an average size of ca. 2.41 nm, which are then served as seeds for the formation of tiny core–shell Au@Pd nanoparticles with different Au/Pd molar ratios. The strong electronic coupling between Au core and Pd shell endows the Pd shell with an electronic structure favorable for the ethanol oxidation reaction. In specific, the ionic liquidderived core–shell Au@Pd nanoparticles at an Au/Pd molar ratio of 1/1 exhibit the highest mass-and area-based activities, approximately 11 times than those of commercial Pd/C catalyst for ethanol electrooxidation.展开更多
A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an eth...A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichlorometh- ane with an efficiency of 〉96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.展开更多
Heterogeneous nanostructures that are defined as a hybrid structure consisting of two or more nanoscale domains with distinct chemical compositions or physical characteristics have attracted intense efforts in recent ...Heterogeneous nanostructures that are defined as a hybrid structure consisting of two or more nanoscale domains with distinct chemical compositions or physical characteristics have attracted intense efforts in recent years.In this review,we focus on the introduction of a number of heterogeneous nanostructures derived using core-shell Ag-Pt nanoparticles as starting materials,including hollow,dimeric and composite structures and also highlight their application in catalyzing electrochemical reactions,e.g.,methanol oxidation reaction and oxygen reduction reaction.This review not only shows the capability of core-shell Ag-Pt nanoparticles in producing various heterogeneous nanostructures as starting templates,but also highlights the structural design or electronic interaction that endows the heterogeneous nanostructures with enhanced catalytic properties either in methanol oxidation or in oxygen reduction.Further,we also make some perspectives for more heterogeneous nanostructures that may be prepared by using core-shell Ag-Pt particles or their derivatives so as to offer the readers the opportunities and challenges in this field.展开更多
A novel strategy to synthesize copper-based nanoparticles supported on carbon nitride(C3 N4) was developed by popping of mixture containing C3 N4 and cupric nitrate. Characterizations such as X-ray photoelectron spect...A novel strategy to synthesize copper-based nanoparticles supported on carbon nitride(C3 N4) was developed by popping of mixture containing C3 N4 and cupric nitrate. Characterizations such as X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) indicate that the structure of g-C3 N4 maintained although a popping process occurred. High resolution transmission electronic microscopy(HRTEM) characterization illustrated that copper-based nanoparticles with diameter of < 1 nm were well distributed on g-C3 N4. This kind of copper catalyst exhibits high catalytic activity and selectivity in arylation of pyrazole, a simple and effect strategy to construct C-N bond in organic chemistry.According to the results of control experiments and characterizations, cuprous oxide should be the catalytic active phase in the supported coperbased catalyst.展开更多
The regeneration of articular cartilage remains a great challenge due to the difficulty in effectively enhancing spontaneous healing.Recently,the combination of implanted stem cells,suitable biomaterials and bioactive...The regeneration of articular cartilage remains a great challenge due to the difficulty in effectively enhancing spontaneous healing.Recently,the combination of implanted stem cells,suitable biomaterials and bioactive molecules has attracted attention for tissue regeneration.In this study,a novel injectable nanocomposite was rationally designed as a sustained release platform for enhanced cartilage regeneration through integration of a chitosan-based hydrogel,articular cartilage stem cells(ACSCs)and mesoporous SiO_(2)nanoparticles loaded with anhydroicaritin(AHI).The biocompatible engineered nanocomposite acting as a novel 3D biomimetic extracellular matrix exhibited a remarkable sustained release effect due to the synergistic regulation of the organic hydrogel framework and mesopore channels of inorganic mSiO_(2)nanoparticles(mSiO_(2)NPs).Histological assessment and biomechanical tests showed that the nanocomposites exhibited superior performance in inducing ACSCs proliferation and differentiation in vitro and promoting extracellular matrix(ECM)production and cartilage regeneration in vivo.Such a novel multifunctional biocompatible platform was demonstrated to significantly enhance cartilage regeneration based on the sustained release of AHI,an efficient bioactive natural small molecule for ACSCs chondrogenesis,within the hybrid matrix of hydrogel and mSiO_(2)NPs.Hence,the injectable nanocomposite holds great promise for use as a 3D biomimetic extracellular matrix for tissue regeneration in clinical diagnostics.展开更多
PIP5k1βis crucial to the generation of phosphotidylinosotol(4,5)P2.PIP5k1βparticipates in numerous cellular activities,such as B cell and platelet activation,cell phagocytosis and endocytosis,cell apoptosis,and cyto...PIP5k1βis crucial to the generation of phosphotidylinosotol(4,5)P2.PIP5k1βparticipates in numerous cellular activities,such as B cell and platelet activation,cell phagocytosis and endocytosis,cell apoptosis,and cytoskeletal organization.In the present work,we aimed to examine the function of PIP5k1βin osteoclastogenesis and osteogenesis to provide promising strategies for osteoporosis prevention and treatment.We discovered that PIP5k1β deletion in mice resulted in obvious bone loss and that PIP5k1β was highly expressed during both osteoclast and osteoblast differentiation.Deletion of the gene was found to enhance the proliferation and migration of bone marrow-derived macrophage-like cells to promote osteoclast differentiation.PIP5k1β-/-osteoclasts exhibited normal cytoskeleton architecture but stronger resorption activity.PIP5kip deficiency also promoted activation of mitogen-activated kinase and Akt signaling,enhanced TRAF6 and c-Fos expression,facilitated the expression and nuclear translocation of NFATC1,and upregulated Grb2 expression,thereby accelerating osteoclast differentiation and function.Finally,PIP5k1β enhanced osteoblast differentiation by upregulating master gene expression through triggering smad1/5/8 signaling.Therefore,PIP5k1βmodulates bone homeostasis and remodeling.展开更多
of main observation and conclusion The extraction of Li^+from the high Mg/Li ratio brine was performed using hydroxyl functional ionic lic-uids(ILs)as the coextractant and tributyl phosphate(TBP)as the extractant.irst...of main observation and conclusion The extraction of Li^+from the high Mg/Li ratio brine was performed using hydroxyl functional ionic lic-uids(ILs)as the coextractant and tributyl phosphate(TBP)as the extractant.irsty the extractive system,1-2-hydroxyethyl-3-mnethylimidazolumbis(trifuoromethylsulfonyl)imide([HOEmim][NTf2])+TBP was proved to exhibit the highest extraction efficiency of Li^+(88.15%)from LiCl aqueous solutions among the extractants composed of differents TB P,and ls+TBP.Effects of various extraction parameters on the extraction eficiencies of Li^+and Mg^2+were then investigated.95.01%of Li^+was extracted and the Li^+/Mg^2+separation factor reached 405.76 in a singl-stage at 278.15 Kand O/A of 2:1.The extraction complexes were determined by the slope analysis method and ESI-MS analysis,and the metal complexes in the organic phase were indcated to be mainly[L-2TBP][NTf;J.The striping study showed that 92.86%of i*was stripped with 1.0 mol·L^-1 HCl.98%extraction capacity of the synergyextractants was remained after 5 regeneration cycles.The thermodynamic parameters(△G°,△H°,and△S°),together with the mechanism of the Li^+extraction were further demonstrated finally,According to the results,[HOEmim][NTf2]+TBP extraction system showed promising performance in extracting lithium from salt lake brine with high Mg/Li ratio.展开更多
Noble metal nanoparticles with hollow interiors and customizable shell com- positions have immense potential for a wide variety of applications. Herein, we present a facile, general, and cost-effective strategy for th...Noble metal nanoparticles with hollow interiors and customizable shell com- positions have immense potential for a wide variety of applications. Herein, we present a facile, general, and cost-effective strategy for the synthesis of noble metal nanoparticles with hollow structures, which is based on the inside-out diffusion of Ag in solid-state core-shell nanoparticles. This approach starts with the preparation of core-shell nanoparticles with Ag residing in the core region, which are then loaded on a solid substrate and aged in air to allow the inside-out diffusion of Ag from the core region, leading to the formation of monometallic or alloy noble metal nanoparticles with a hollow interior. The synthesis was carried out at room temperature and could be achieved on different solid substrates. In particular, the inside-out diffusion of Ag calls for specific concern with respect to the evaluation of the catalytic performance of the Ag-based core--shell nanoparticles since it may potentially interfere with the physical and chemical properties of the core-shell particles.展开更多
Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis.We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors a...Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis.We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors at an appropriate ratio with the subsequent phosphating at an elevated temperature for forming heterogeneous nanocomposites consisting of quasi-spherical Pt_(3)Co alloy domains and rod-like CoP_(2) domains for high-efficiency methanol electrooxidation.The strong electronic coupling between Pt_(3)Co and CoP_(2) domains in the nanocomposites render the electron density around Pt atoms to decrease,which is favorable for reducing the adsorption of poisoning CO-like intermediates on the catalyst surfaces.Accordingly,the as-prepared heterogeneous Pt_(3)Co–CoP_(2) nanocomposites show good performance for methanol electrooxidation both in acidic and alkaline media.In specific,at a Pt loading of only 6.4%on a common carbon substrate,the mass-based activity of Pt_(3)Co–CoP_(2) nanocomposites in an acidic medium is about 2 and 1.5 times as high as that of commercial Pt/C catalyst(20%mass loading)and home-made Pt_(3)Co alloy nanoparticles(8.0%mass loading),while in the alkaline medium,these values are 3 and 2,respectively.展开更多
A facile hydrothermal approach is used to synthesize hollow silver nanoparticles, labeled as hAgNPs, involving an initial formation of metal complexes from Ag＋ ion precursors and dodecylamine in a water]ethanol mixtu...A facile hydrothermal approach is used to synthesize hollow silver nanoparticles, labeled as hAgNPs, involving an initial formation of metal complexes from Ag＋ ion precursors and dodecylamine in a water]ethanol mixture at room temperature and a subsequent reduction in an autoclave at elevated temperature. A number of characterization techniques are used to characterize the structure and chem- ical composition of the as-formed hAgNPs, and to understand the mechanism behind the formation, The notable simplicity renders this synthetic approach promising for creating hAgNPs on a large scale for a given technological application, and the mechanistic understanding may provide new opportunities to design and fabricate other hollow nanostructures.展开更多
基金Supported by the National Natural Sciences Foundation of China(91434107,21506232)National Key Projects for Fundamental Research and Development of China(2016YFB0600903)
文摘A large number of surplus glycerol from the biodiesel production can be used as renewable feedstock to produce glycerol carbonate. In this paper, a series of guanidine-based ionic liquids were synthesized to catalyze the transesterification of glycerol and dimethyl carbonate. The tunable basicity and the anion–cation cooperative effect were responsible for the obtained results. The [TMG][TFE] showed the best activity turnover frequency(TOF)of 1754.0 h^(-1), glycerol(GL) conversion of 91.8%, glycerol carbonate(GC) selectivity of 95.5%) at 80 °C with 0.1 mol% catalyst for 30 min. The reaction mechanism of the transesterification was also proposed.
基金supported by the National Natural Science Foundation of China(21573240,21706265,21776292)National Natural Science Foundation of Beijing(2173062)+1 种基金the Center for Mesoscience,Institute of Process Engineering,Chinese Academy of Sciences(MPCS-2017-A-02)State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences(MPCS2019-A-09)。
文摘To maximize the size and structural advantages of nanomaterials in electrooxidation of ethanol, we herein report the synthesis of core–shell gold(Au)@Palladium(Pd) nanoparticles smaller than 3 nm in an ionic liquid, which combines the advantages of ionic liquids in preparing fine metal nanoparticles with the benefits of core–shell nanostructures. This synthetic strategy relies on the use of an ionic liquid(1-(2'-aminoethyl)-3-methyl-imidazolum tetrafluoroborate) as a stabilizer to produce Au particles with an average size of ca. 2.41 nm, which are then served as seeds for the formation of tiny core–shell Au@Pd nanoparticles with different Au/Pd molar ratios. The strong electronic coupling between Au core and Pd shell endows the Pd shell with an electronic structure favorable for the ethanol oxidation reaction. In specific, the ionic liquidderived core–shell Au@Pd nanoparticles at an Au/Pd molar ratio of 1/1 exhibit the highest mass-and area-based activities, approximately 11 times than those of commercial Pd/C catalyst for ethanol electrooxidation.
基金supported by the 100 Talents Program of the Chinese Academy of Sciences, National Natural Science Foundation of China (Nos. 21173226, 21376247)State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences (Nos. MPCS-2011-D-08, MPCS-2010-C-02)
文摘A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichlorometh- ane with an efficiency of 〉96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards.
基金Financial supports from the Beijing Natural Science Foundation(No.Z200012)National Natural Science Foundation of China(Nos.22075290,21972068,21776292 and 21706265)State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences(No.MPCS-2019-A-09)。
文摘Heterogeneous nanostructures that are defined as a hybrid structure consisting of two or more nanoscale domains with distinct chemical compositions or physical characteristics have attracted intense efforts in recent years.In this review,we focus on the introduction of a number of heterogeneous nanostructures derived using core-shell Ag-Pt nanoparticles as starting materials,including hollow,dimeric and composite structures and also highlight their application in catalyzing electrochemical reactions,e.g.,methanol oxidation reaction and oxygen reduction reaction.This review not only shows the capability of core-shell Ag-Pt nanoparticles in producing various heterogeneous nanostructures as starting templates,but also highlights the structural design or electronic interaction that endows the heterogeneous nanostructures with enhanced catalytic properties either in methanol oxidation or in oxygen reduction.Further,we also make some perspectives for more heterogeneous nanostructures that may be prepared by using core-shell Ag-Pt particles or their derivatives so as to offer the readers the opportunities and challenges in this field.
基金supported the following funders: One Hundred Talent Project of Hebei Province (Grant No. E2016100015)National Natural Science Foundation of China (No. 21773053)+2 种基金Hebei provincial Natural Science Foundation (No. B2017201084)Hebei Provincial Technology Foundation for High-level talents (No. CL201601)the science technology research and development guidance program project of Baoding City (No. 16ZF027)
文摘A novel strategy to synthesize copper-based nanoparticles supported on carbon nitride(C3 N4) was developed by popping of mixture containing C3 N4 and cupric nitrate. Characterizations such as X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) indicate that the structure of g-C3 N4 maintained although a popping process occurred. High resolution transmission electronic microscopy(HRTEM) characterization illustrated that copper-based nanoparticles with diameter of < 1 nm were well distributed on g-C3 N4. This kind of copper catalyst exhibits high catalytic activity and selectivity in arylation of pyrazole, a simple and effect strategy to construct C-N bond in organic chemistry.According to the results of control experiments and characterizations, cuprous oxide should be the catalytic active phase in the supported coperbased catalyst.
基金supported by grants from The Ministry of Science and Technology of China(2020YFC2002800)the National Natural Science Foundation of China(81830078,21875044),NO.2021-NCRC-CXJJ-ZH-35 of Clinical Application-oriented Medical Innovation Foundation from National Clinical Research Center for Orthopedics,Sports Medicine&Rehabilitation and Jiangsu China-Israel Industrial Technical Research Institute Foundation,Sino-Swiss collaborative project from Ministry of Science and Technology(2015DFG32200)+1 种基金Science and Technology Commission of Shanghai Municipality(No.19XD1434100,19ZR1433100)Shanghai Jiaotong University“Cross research fund of Medical Engineering”(YG2019ZDA22).
文摘The regeneration of articular cartilage remains a great challenge due to the difficulty in effectively enhancing spontaneous healing.Recently,the combination of implanted stem cells,suitable biomaterials and bioactive molecules has attracted attention for tissue regeneration.In this study,a novel injectable nanocomposite was rationally designed as a sustained release platform for enhanced cartilage regeneration through integration of a chitosan-based hydrogel,articular cartilage stem cells(ACSCs)and mesoporous SiO_(2)nanoparticles loaded with anhydroicaritin(AHI).The biocompatible engineered nanocomposite acting as a novel 3D biomimetic extracellular matrix exhibited a remarkable sustained release effect due to the synergistic regulation of the organic hydrogel framework and mesopore channels of inorganic mSiO_(2)nanoparticles(mSiO_(2)NPs).Histological assessment and biomechanical tests showed that the nanocomposites exhibited superior performance in inducing ACSCs proliferation and differentiation in vitro and promoting extracellular matrix(ECM)production and cartilage regeneration in vivo.Such a novel multifunctional biocompatible platform was demonstrated to significantly enhance cartilage regeneration based on the sustained release of AHI,an efficient bioactive natural small molecule for ACSCs chondrogenesis,within the hybrid matrix of hydrogel and mSiO_(2)NPs.Hence,the injectable nanocomposite holds great promise for use as a 3D biomimetic extracellular matrix for tissue regeneration in clinical diagnostics.
基金This work was supported by grants from the National Natural Science Foundation of China(81830078,81772347,and 81572123)Science and Technology Commission of Shanghai Municipality(19XD1434100 and 16430723500)+1 种基金Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support(2016131A)Shanghai Jiao Tong University-The Chinese University of Hong Kong joint Research Collaboration Fund.
文摘PIP5k1βis crucial to the generation of phosphotidylinosotol(4,5)P2.PIP5k1βparticipates in numerous cellular activities,such as B cell and platelet activation,cell phagocytosis and endocytosis,cell apoptosis,and cytoskeletal organization.In the present work,we aimed to examine the function of PIP5k1βin osteoclastogenesis and osteogenesis to provide promising strategies for osteoporosis prevention and treatment.We discovered that PIP5k1β deletion in mice resulted in obvious bone loss and that PIP5k1β was highly expressed during both osteoclast and osteoblast differentiation.Deletion of the gene was found to enhance the proliferation and migration of bone marrow-derived macrophage-like cells to promote osteoclast differentiation.PIP5k1β-/-osteoclasts exhibited normal cytoskeleton architecture but stronger resorption activity.PIP5kip deficiency also promoted activation of mitogen-activated kinase and Akt signaling,enhanced TRAF6 and c-Fos expression,facilitated the expression and nuclear translocation of NFATC1,and upregulated Grb2 expression,thereby accelerating osteoclast differentiation and function.Finally,PIP5k1β enhanced osteoblast differentiation by upregulating master gene expression through triggering smad1/5/8 signaling.Therefore,PIP5k1βmodulates bone homeostasis and remodeling.
基金This work was supported by the National Natural Science Foundation of china(Nos.21978302,21706257 and 21776292)Innovation Academy for Green Manufacture(IAGM2020DB05)Major Program of National Natural Science Foundation of China(No.21890762).This paper was completed under the guid-ance of Professor Suojiang Zhang.
文摘of main observation and conclusion The extraction of Li^+from the high Mg/Li ratio brine was performed using hydroxyl functional ionic lic-uids(ILs)as the coextractant and tributyl phosphate(TBP)as the extractant.irsty the extractive system,1-2-hydroxyethyl-3-mnethylimidazolumbis(trifuoromethylsulfonyl)imide([HOEmim][NTf2])+TBP was proved to exhibit the highest extraction efficiency of Li^+(88.15%)from LiCl aqueous solutions among the extractants composed of differents TB P,and ls+TBP.Effects of various extraction parameters on the extraction eficiencies of Li^+and Mg^2+were then investigated.95.01%of Li^+was extracted and the Li^+/Mg^2+separation factor reached 405.76 in a singl-stage at 278.15 Kand O/A of 2:1.The extraction complexes were determined by the slope analysis method and ESI-MS analysis,and the metal complexes in the organic phase were indcated to be mainly[L-2TBP][NTf;J.The striping study showed that 92.86%of i*was stripped with 1.0 mol·L^-1 HCl.98%extraction capacity of the synergyextractants was remained after 5 regeneration cycles.The thermodynamic parameters(△G°,△H°,and△S°),together with the mechanism of the Li^+extraction were further demonstrated finally,According to the results,[HOEmim][NTf2]+TBP extraction system showed promising performance in extracting lithium from salt lake brine with high Mg/Li ratio.
文摘Noble metal nanoparticles with hollow interiors and customizable shell com- positions have immense potential for a wide variety of applications. Herein, we present a facile, general, and cost-effective strategy for the synthesis of noble metal nanoparticles with hollow structures, which is based on the inside-out diffusion of Ag in solid-state core-shell nanoparticles. This approach starts with the preparation of core-shell nanoparticles with Ag residing in the core region, which are then loaded on a solid substrate and aged in air to allow the inside-out diffusion of Ag from the core region, leading to the formation of monometallic or alloy noble metal nanoparticles with a hollow interior. The synthesis was carried out at room temperature and could be achieved on different solid substrates. In particular, the inside-out diffusion of Ag calls for specific concern with respect to the evaluation of the catalytic performance of the Ag-based core--shell nanoparticles since it may potentially interfere with the physical and chemical properties of the core-shell particles.
基金supported by the Beijing Natural Science Foundation(Grant No.Z200012)National Natural Science Foundation of China(Grant Nos.22075290,21972068,21776292,21706265)+1 种基金State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences(MPCS-2019-A-09)Nanjing IPE Institute of Green Manufacturing Industry are gratefully acknowledged.
文摘Heterogeneous nanocomposites comprising chemically distinct constituents are particularly promising in electrocatalysis.We herein report a synthetic strategy that combines the reduction of Pt and Co ionic precursors at an appropriate ratio with the subsequent phosphating at an elevated temperature for forming heterogeneous nanocomposites consisting of quasi-spherical Pt_(3)Co alloy domains and rod-like CoP_(2) domains for high-efficiency methanol electrooxidation.The strong electronic coupling between Pt_(3)Co and CoP_(2) domains in the nanocomposites render the electron density around Pt atoms to decrease,which is favorable for reducing the adsorption of poisoning CO-like intermediates on the catalyst surfaces.Accordingly,the as-prepared heterogeneous Pt_(3)Co–CoP_(2) nanocomposites show good performance for methanol electrooxidation both in acidic and alkaline media.In specific,at a Pt loading of only 6.4%on a common carbon substrate,the mass-based activity of Pt_(3)Co–CoP_(2) nanocomposites in an acidic medium is about 2 and 1.5 times as high as that of commercial Pt/C catalyst(20%mass loading)and home-made Pt_(3)Co alloy nanoparticles(8.0%mass loading),while in the alkaline medium,these values are 3 and 2,respectively.
文摘A facile hydrothermal approach is used to synthesize hollow silver nanoparticles, labeled as hAgNPs, involving an initial formation of metal complexes from Ag＋ ion precursors and dodecylamine in a water]ethanol mixture at room temperature and a subsequent reduction in an autoclave at elevated temperature. A number of characterization techniques are used to characterize the structure and chem- ical composition of the as-formed hAgNPs, and to understand the mechanism behind the formation, The notable simplicity renders this synthetic approach promising for creating hAgNPs on a large scale for a given technological application, and the mechanistic understanding may provide new opportunities to design and fabricate other hollow nanostructures.
