Two‐dimensional(2D)materials have atomic thickness,and thickness‐dependent electronic transport,optical and thermal properties,high-lighting great promise applications in future semiconductor devices.Chemical vapor ...Two‐dimensional(2D)materials have atomic thickness,and thickness‐dependent electronic transport,optical and thermal properties,high-lighting great promise applications in future semiconductor devices.Chemical vapor deposition(CVD)is considered as an industry‐oriented method for macro‐synthesis of 2D materials.In conventional CVD,high temperatures are required for the synthesis of high‐quality large‐size 2D materials,which is incompatible with of back‐end‐of‐line of the complementary metal oxide semiconductor(CMOS)techniques.There-fore,low‐temperature synthesis of 2D materials is of critical importance for the advancement toward practical applications of 2D materials with the CMOS technologies.In this review,we focus on strategies for the low‐temperature growth of 2D materials,including the use of low‐melting‐point precursors,metal‐organic CVD,plasma‐enhanced CVD,van der Waals‐substrate vapor phase epitaxy,tellurium‐assisted CVD,salt‐assisted CVD,etc.,with discussions of their reaction mechanisms,ap-plications,associated advantages,and limitations.We also provide an outlook and perspectives of future low‐temperature chemical vapor deposition growth of 2D materials.展开更多
The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence propert...The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.展开更多
The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to ...The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to modulate its catalytic HOR performance,but at the cost of mass activity due to the coverage of modifiers on Pt surface.Herein,we constructed dual junctions'Pt/nitrogen-doped carbon(Pt/NC)andδ-MoC/NC to modify electronic structure of Pt via interfacial electron transfer to acquire Pt-MoC@NC catalyst with electron-deficient Pt nanoparticles,simultaneously endowing it with high mass activity and durability of alkaline HOR.Moreover,the unique structure of Pt-MoC@NC endows Pt with a high COtolerance at 1,000 ppm CO/H_(2),a quality that commercial Pt-C catalyst lacks.The theoretical calculations not only confirm the diffusion of electrons from Pt/NC to Mo C/NC could occur,but also demonstrate the negative shift of Pt d-band center for the optimized binding energies of*H,*OH and CO.展开更多
Spun-bond non-woven fabrics(NWFs)made of porous C-shaped polypropylene fibers were applied in rapid oil absorption and effective on-line oil spillage monitoring.It is of great interest to further optimize the absorpti...Spun-bond non-woven fabrics(NWFs)made of porous C-shaped polypropylene fibers were applied in rapid oil absorption and effective on-line oil spillage monitoring.It is of great interest to further optimize the absorption properties of these materials by tuning their preparation parameters as well as characterize them with theoretical models.In this paper,effects of die shape,diluent composition(mixtures of dibutyl and dioctyl phthalate),and drawing speed on their porous structure and oil-absorbing performance were systematically investigated and characterized based on two novel concepts,i.e.,the equivalent capillary tube pore radius and the kinetic pore tortuosity(barrier to access)derived from the simplest capillary tube liquid-filling model.The use of higher dibutyl phthalate fractions under faster drawing speeds resulted in the formation of larger and more connected inner filament sub-micron pores.Three stages of tube filling relating to inter-filament large pores,medium pores close to bonding points,and inner filament small pores were observed in the spun-bond NWFs.Continuous oil recovery rates of 986 L·m^(-2)·h^(-1) with an oil/water selectivity of 6.4 were achieved in dynamic skimming experiments using simulated spilled oil.展开更多
A three-layered phosphor structure was designed and prepared by the spin coating of BaSi_(2)N_(2)O_(2):Eu(cyan-emitting)and(Sr,Ca)AlSiN_(3):Eu(red-emitting)phosphor films on the yellowemitting Y_(3)Al_(5)O_(12):Ce(YAG...A three-layered phosphor structure was designed and prepared by the spin coating of BaSi_(2)N_(2)O_(2):Eu(cyan-emitting)and(Sr,Ca)AlSiN_(3):Eu(red-emitting)phosphor films on the yellowemitting Y_(3)Al_(5)O_(12):Ce(YAG:Ce)phosphor ceramic synthesized by the solid-state reaction under vacuum sintering.In order to achieve high color rendering lighting,the influence of the composition and structure of the three-layered phosphors on the optical,thermal,and electrical properties of the chip-on-board(COB)packaged white-light-emitting diodes(WLEDs)was studied systematically.The WLED with the structure of“red+cyan+yellow”(R+C+Y)three-layered phosphor generated neutral white light and had a luminous efficacy of 75 lm/W,the fidelity index(R_(f))of 93,the gamut index(R_(g))of 97,and the correlated color temperature(CCT)of 3852 K.Under the excitation of laser diode(LD),the layer-structured phosphor yielded the white light with a luminous efficacy of 120 lm/W,color rendering index(CRI)of 90,and CCT of 5988 K.The result indicates that the three-layered phosphor structure is a promising candidate to achieve high color rendering and high luminous efficacy lighting.展开更多
The major advantage of laser lighting over white light-emitting-diode is the possibility to achieve ultra-high luminance.However,phosphors usually suffer laser-induced luminescence saturation,which limits the peak lum...The major advantage of laser lighting over white light-emitting-diode is the possibility to achieve ultra-high luminance.However,phosphors usually suffer laser-induced luminescence saturation,which limits the peak luminance of laser lighting devices.The aim of the present study is to develop LuAG:Ce/Al_(2)O_(3)composite ceramics(LACCs)with a high saturation threshold for high-luminance laser lighting.Owning to the rigid crystal structure,proper synthetic process,and optimized thermal design,the LACCs possess small thermal quenching(16%loss in luminescence at 225℃),high quantum yield(>95%),and excellent luminescence properties.When the LACCs are irradiated by blue laser diodes in a reflection mode,a high luminous flux of 4634 lm and luminous efficacy of 283 lm·W^(−1)are realized.Furthermore,they show no sign of luminescence saturation even when the power density reaches 20.5 W·mm^(−2).With these favorable properties,the designed LACCs show great potential in high-luminance laser lighting.展开更多
Phosphor in glass（PiG） employing Ce:Y3Al5O12（YAG）-doped boro-bismuthate glass via low-temperature cosintering technology was successfully prepared, using Bi2O3-B2O3-ZnO glass as the base material. The photolumines...Phosphor in glass（PiG） employing Ce:Y3Al5O12（YAG）-doped boro-bismuthate glass via low-temperature cosintering technology was successfully prepared, using Bi2O3-B2O3-ZnO glass as the base material. The photoluminescence（PL） of PiG co-sintered at times ranging from 20 min to 60 min at 700°C was investigated.As a result, the relative PL intensity of PiG under a reducing atmosphere of CO showed significant enhancement of about 7–14 times that under air atmosphere sintering for 20–50 min. The PL intensity decreased gradually with the co-sintering time, which may be due to the corrosion of the YAG lattice structure.展开更多
An efficient zinc-catalyzed oxidative cyclization of readily available indoly ynamides has been developed,enabling rapid and practical access to a diverse array of valuable medium-sized lactams in mostly good to excel...An efficient zinc-catalyzed oxidative cyclization of readily available indoly ynamides has been developed,enabling rapid and practical access to a diverse array of valuable medium-sized lactams in mostly good to excellent yields with wide substrate scope.In addition,such an asymmetric synthesis has also been explored by employing the chiral substrate.展开更多
Platinum based alloys are hereinto the mostly used methanol oxidation catalysts.However,there are limited ways to improve the methanol oxidation reaction(MOR)performance of catalysts in terms of both activity and stab...Platinum based alloys are hereinto the mostly used methanol oxidation catalysts.However,there are limited ways to improve the methanol oxidation reaction(MOR)performance of catalysts in terms of both activity and stability.Herein we developed a simple heat-treatment method to synthesize PtCu_(3)/C intermetallic compound catalyst with lattice compression.The as-prepared PtCu_(3)/C-1000 exhibited high specific activity of 3.23 mA·cm^(-1) and mass activity of 1,200 mA·mgPt^(-1),which is much higher than the PtCu_(3)/C-untreated and commercial Pt/C catalysts,respectively.The XAS and DFT results shows the high activity of the catalyst towards MOR comes from the tightening of the Pt-M bond,which leads to the decrease of Fermi energy level and the make it difficulty in adsorbing carbon intermediates,thus releasing more active sites to promote the improvement of MOR performance.Moreover,the PtCu_(3)/C-1000 shows better stability which is due to the surface-rich Pt prevents Cu from dissolution.展开更多
There are many strategies to maintain the excellent photoluminescence(PL) characteristics of perovskite quantum dots(QDs). Here, we proposed a facile and effective method to prepare cyan CsPb(Cl/Br)3/SiO2 nanospheres ...There are many strategies to maintain the excellent photoluminescence(PL) characteristics of perovskite quantum dots(QDs). Here, we proposed a facile and effective method to prepare cyan CsPb(Cl/Br)3/SiO2 nanospheres at room temperature. Cubic CsPb(Cl/Br)3 was obtained by adding a LiCl-H2O solution and anion exchange reaction. With(3-aminopropyl)triethoxysilane as an auxiliary agent, a QDs/SiO2 composite was extracted from a sol-gel solution by precipitate-encapsulation method. The transmission electron microscopy images and Fourier transform infrared spectra indicated the QDs were indeed embedded in silica substances.Besides, humidity stability and thermal stability show the composite possesses a great application value.Finally, cyan QDs@SiO2 powder has a high PL quantum yield of up to 84%;the stable cyan fluorescent powder does have great potential to play a key role in commercial full spectrum display.展开更多
Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2....Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2.0]compounds in generally good to excellent yields with broad substrate scope under mild reaction conditions.Importantly,this protocol not only constitutes a rare example of non-noble metal-catalyzed alkyne carbocyclization,but also represents a rare cyclization on the B-position ofπu-tethered ynamides.The possibility of asymmetric carbocyclization via kinetic resolution also emerges.展开更多
Two-dimensional(2D)metal oxide α-MoO_(3) shows great potentials because of its very high dielectric constant,air stability and anisotropic phonon polaritons.However,a method to produce ultrathin single crystallineα-...Two-dimensional(2D)metal oxide α-MoO_(3) shows great potentials because of its very high dielectric constant,air stability and anisotropic phonon polaritons.However,a method to produce ultrathin single crystallineα-MoO_(3) with high transferability for functional device architecture is lacking.Herein,we report on the controllable synthesis of ultrathinα-MoO_(3) single crystals via chemical vapor deposition(CVD)assisted by plasma pretreatment.We also carried out systematic computational work to explicate the mechanism for the slantly-oriented growth of thin nanosheets on plasma-pretreated substrate.The method possesses certain universality to synthesize other ultrathin oxide materials,such as Bi_(2)O_(3) and Sb_(2)O_(3) nanosheets.As-grownα-MoO_(3) presents a high dielectric constant(≈40),ultrathin thickness(≈3 nm)and high transferability.Memristors withα-MoO_(3) as the functional layers show excellent performance featuring high on/off ratio of approximately 104,much lower set voltage around 0.5 V,and highly repetitive voltage sweep endurance.The power consumption of MoO_(3) memristors is significantly reduced,resulted from reduced thickness of the MoO_(3) nanosheets.Single crystal ultrathinα-MoO_(3) shows great potentials in post-Moore memristor and the synthesis of CVD assisted by plasma pretreatment approach points to a new route for materials growth.展开更多
Flexible photodetectors(FPDs)have been receiving increasing attention in recent years because of their potential applications in electronic eyes,bioinspired sensing,smart textiles,and wearable devices.Moreover,metal h...Flexible photodetectors(FPDs)have been receiving increasing attention in recent years because of their potential applications in electronic eyes,bioinspired sensing,smart textiles,and wearable devices.Moreover,metal halide perovskites(MHPs)with outstanding optical and electrical properties,good mechanical flexibility,lowcost and low-temperature solution-processed fabrication have become promising candidates as light harvesting materials in FPDs.Herein,we comprehensively review the developments of FPDs based on MHPs reported recently.This review firstly provides an introduction with respect to the performance parameters and device configurations of perovskite photodetectors,followed by the specific requirements of FPDs including substrate and electrode materials.Next,chemical compositions,structures and preparation methods of MHPs are presented.Then,the FPDs on the basis of single-component perovskite and hybrid structure perovskite are discussed,subsequently,self-powered flexible perovskite photodetectors were presented.In the end,conclusions and challenges are put forward in the field of FPDs based on perovskites.展开更多
Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and env...Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and environmental friendliness. In this work, we prepared a series of boron-doped covalent triazine frameworks and found that boron doping can significantly improve the CO selectivity up to 91.2% in the CO_(2) electroreduction reactions(CO_(2)RR). The effect of different doping ratios on the activity by adjusting the proportion of doped atoms was systematically investigated. This work proves that the doping modification of non-metallic materials is a very effective way to improve their activity, and also lays a foundation for the study of other element doping in the coming future.展开更多
Direct functionalization of inert C(sp^(3))–H bonds is a topic of immense contemporary interest and exceptional value in organic synthesis.The recent research has established a novel and practical protocol which feat...Direct functionalization of inert C(sp^(3))–H bonds is a topic of immense contemporary interest and exceptional value in organic synthesis.The recent research has established a novel and practical protocol which features the engagement of vinyl cation species to functionalize C(sp^(3))–H bonds.The discussion of the topic is arranged by the strategies to generate the reactive intermediates,including ionization of vinyl triflates,addition of electrophiles to alkynes,tandem cyclization of enynes or diynes,and decomposition ofβ-hydroxy-α-diazo ketones.This review closes with a personal perspective on the dynamic research area of unactivated C(sp^(3))–H functionalization via vinyl cations.Hopefully,it will provide timely illumination and beneficial guidance for organic chemists who are interested in this area.Meanwhile continued development of the field is strongly anticipated in the future.展开更多
基金Key Programs for Science and Technology Innovation of Wenzhou,Grant/Award Number:ZG2022037National Natural Science Foundation of China,Grant/Award Numbers:51902061,52072272,52331009,62304157。
文摘Two‐dimensional(2D)materials have atomic thickness,and thickness‐dependent electronic transport,optical and thermal properties,high-lighting great promise applications in future semiconductor devices.Chemical vapor deposition(CVD)is considered as an industry‐oriented method for macro‐synthesis of 2D materials.In conventional CVD,high temperatures are required for the synthesis of high‐quality large‐size 2D materials,which is incompatible with of back‐end‐of‐line of the complementary metal oxide semiconductor(CMOS)techniques.There-fore,low‐temperature synthesis of 2D materials is of critical importance for the advancement toward practical applications of 2D materials with the CMOS technologies.In this review,we focus on strategies for the low‐temperature growth of 2D materials,including the use of low‐melting‐point precursors,metal‐organic CVD,plasma‐enhanced CVD,van der Waals‐substrate vapor phase epitaxy,tellurium‐assisted CVD,salt‐assisted CVD,etc.,with discussions of their reaction mechanisms,ap-plications,associated advantages,and limitations.We also provide an outlook and perspectives of future low‐temperature chemical vapor deposition growth of 2D materials.
基金Project supported by the Science and Technology Planning Project of Zhejiang Province,China(Grant No.2018C01046)Enterprise-funded Latitudinal Research Projects,China(Grant Nos.J2016-141,J2017-171,J2017-293,and J2017-243)
文摘The color conversion glass ceramics which were made of borosilicate matrix co-doped(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors were prepared by two-step method in co-sintering. The change in luminescence properties and the drift of chromaticity coordinates(CIE) of the(SrBaSm)Si2O2N2:(Eu^3+Ce^3+) blue-green phosphors and the color conversion glass ceramics were studied in the sintering temperature range from 600℃ to 800℃. The luminous intensity and internal quantum yield(QY) of the blue-green phosphors and glass ceramics decreased with the sintering temperature increasing. When the sintering temperature increased beyond 750℃, the phosphors and the color conversion glass ceramics almost had no peak in photoluminescence(PL) and excitation(PLE) spectra. The results showed that the blue-green phosphors had poor thermal stability at higher temperature. The lattice structure of the phosphors was destroyed by the glass matrix and the Ce^3+ in the phosphors was oxidized to Ce^4+, which further caused a decrease in luminescent properties of the color conversion glass ceramics.
基金supported by the National Natural Science Foundation of China (Grant Nos.52072272,52171145 and 22109120)the Zhejiang Provincial Natural Science Foundation of China (LQ21B030002)+1 种基金the Zhejiang Provincial Special Support Program for High-level Talents (2019R52042)the Key programs for Science and Technology Innovation of Wenzhou (ZG2022037)。
文摘The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to modulate its catalytic HOR performance,but at the cost of mass activity due to the coverage of modifiers on Pt surface.Herein,we constructed dual junctions'Pt/nitrogen-doped carbon(Pt/NC)andδ-MoC/NC to modify electronic structure of Pt via interfacial electron transfer to acquire Pt-MoC@NC catalyst with electron-deficient Pt nanoparticles,simultaneously endowing it with high mass activity and durability of alkaline HOR.Moreover,the unique structure of Pt-MoC@NC endows Pt with a high COtolerance at 1,000 ppm CO/H_(2),a quality that commercial Pt-C catalyst lacks.The theoretical calculations not only confirm the diffusion of electrons from Pt/NC to Mo C/NC could occur,but also demonstrate the negative shift of Pt d-band center for the optimized binding energies of*H,*OH and CO.
基金supported by the National Natural Science Foundation of China NSFC-U1809213National Natural Science Foundation of China NSFC-21975222.
文摘Spun-bond non-woven fabrics(NWFs)made of porous C-shaped polypropylene fibers were applied in rapid oil absorption and effective on-line oil spillage monitoring.It is of great interest to further optimize the absorption properties of these materials by tuning their preparation parameters as well as characterize them with theoretical models.In this paper,effects of die shape,diluent composition(mixtures of dibutyl and dioctyl phthalate),and drawing speed on their porous structure and oil-absorbing performance were systematically investigated and characterized based on two novel concepts,i.e.,the equivalent capillary tube pore radius and the kinetic pore tortuosity(barrier to access)derived from the simplest capillary tube liquid-filling model.The use of higher dibutyl phthalate fractions under faster drawing speeds resulted in the formation of larger and more connected inner filament sub-micron pores.Three stages of tube filling relating to inter-filament large pores,medium pores close to bonding points,and inner filament small pores were observed in the spun-bond NWFs.Continuous oil recovery rates of 986 L·m^(-2)·h^(-1) with an oil/water selectivity of 6.4 were achieved in dynamic skimming experiments using simulated spilled oil.
基金supported by the National Key R&D Program of China(Grant No.2017YFB0310500)the National Natural Science Foundation of China(Grant No.61775226)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA22010301)the key research project of the frontier science of the Chinese Academy of Sciences(No.QYZDB-SSW-JSC022).
文摘A three-layered phosphor structure was designed and prepared by the spin coating of BaSi_(2)N_(2)O_(2):Eu(cyan-emitting)and(Sr,Ca)AlSiN_(3):Eu(red-emitting)phosphor films on the yellowemitting Y_(3)Al_(5)O_(12):Ce(YAG:Ce)phosphor ceramic synthesized by the solid-state reaction under vacuum sintering.In order to achieve high color rendering lighting,the influence of the composition and structure of the three-layered phosphors on the optical,thermal,and electrical properties of the chip-on-board(COB)packaged white-light-emitting diodes(WLEDs)was studied systematically.The WLED with the structure of“red+cyan+yellow”(R+C+Y)three-layered phosphor generated neutral white light and had a luminous efficacy of 75 lm/W,the fidelity index(R_(f))of 93,the gamut index(R_(g))of 97,and the correlated color temperature(CCT)of 3852 K.Under the excitation of laser diode(LD),the layer-structured phosphor yielded the white light with a luminous efficacy of 120 lm/W,color rendering index(CRI)of 90,and CCT of 5988 K.The result indicates that the three-layered phosphor structure is a promising candidate to achieve high color rendering and high luminous efficacy lighting.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA22010301)the key research project of the frontier science of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-JSC022).
文摘The major advantage of laser lighting over white light-emitting-diode is the possibility to achieve ultra-high luminance.However,phosphors usually suffer laser-induced luminescence saturation,which limits the peak luminance of laser lighting devices.The aim of the present study is to develop LuAG:Ce/Al_(2)O_(3)composite ceramics(LACCs)with a high saturation threshold for high-luminance laser lighting.Owning to the rigid crystal structure,proper synthetic process,and optimized thermal design,the LACCs possess small thermal quenching(16%loss in luminescence at 225℃),high quantum yield(>95%),and excellent luminescence properties.When the LACCs are irradiated by blue laser diodes in a reflection mode,a high luminous flux of 4634 lm and luminous efficacy of 283 lm·W^(−1)are realized.Furthermore,they show no sign of luminescence saturation even when the power density reaches 20.5 W·mm^(−2).With these favorable properties,the designed LACCs show great potential in high-luminance laser lighting.
基金supported by the Science and Technology Planning Project of Zhejiang Province,China(No.2018C01046)the Enterprise-funded Latitudinal Research Projects(Nos.J2016-141,J2017-171,J2017-293,and J2017-243)
文摘Phosphor in glass（PiG） employing Ce:Y3Al5O12（YAG）-doped boro-bismuthate glass via low-temperature cosintering technology was successfully prepared, using Bi2O3-B2O3-ZnO glass as the base material. The photoluminescence（PL） of PiG co-sintered at times ranging from 20 min to 60 min at 700°C was investigated.As a result, the relative PL intensity of PiG under a reducing atmosphere of CO showed significant enhancement of about 7–14 times that under air atmosphere sintering for 20–50 min. The PL intensity decreased gradually with the co-sintering time, which may be due to the corrosion of the YAG lattice structure.
基金the National Natu-ral Science Foundation of China(Nos.21572186,21622204 and 21772161)the Natural Science Foundation of Fujian Province of China(No.2019J02001)+2 种基金the President Research Funds from Xia-men University(No.20720180036)NFFTBS(No.J1310024)PCSIRT,and Science&Technology Cooperation Program of Xia-men(No.3502220183015).
文摘An efficient zinc-catalyzed oxidative cyclization of readily available indoly ynamides has been developed,enabling rapid and practical access to a diverse array of valuable medium-sized lactams in mostly good to excellent yields with wide substrate scope.In addition,such an asymmetric synthesis has also been explored by employing the chiral substrate.
基金This work was supported by the National Natural Science Foundation of China(Nos.51872209 and 51972239)the Key programs for Science and Technology Innovation of Wenzhou(No.2018ZG005).
文摘Platinum based alloys are hereinto the mostly used methanol oxidation catalysts.However,there are limited ways to improve the methanol oxidation reaction(MOR)performance of catalysts in terms of both activity and stability.Herein we developed a simple heat-treatment method to synthesize PtCu_(3)/C intermetallic compound catalyst with lattice compression.The as-prepared PtCu_(3)/C-1000 exhibited high specific activity of 3.23 mA·cm^(-1) and mass activity of 1,200 mA·mgPt^(-1),which is much higher than the PtCu_(3)/C-untreated and commercial Pt/C catalysts,respectively.The XAS and DFT results shows the high activity of the catalyst towards MOR comes from the tightening of the Pt-M bond,which leads to the decrease of Fermi energy level and the make it difficulty in adsorbing carbon intermediates,thus releasing more active sites to promote the improvement of MOR performance.Moreover,the PtCu_(3)/C-1000 shows better stability which is due to the surface-rich Pt prevents Cu from dissolution.
基金supported by the Science and Technology Planning Project of Zhejiang Province(No.2018C01046)Enterprise-Funded Latitudinal Research Projects of China(Nos.J2016-141,J2017-171,J2017-293,and J2017-243)+1 种基金Shanghai Sailing Program(No.18YF1422500)Research Start-Up Project of Shanghai Institute of Technology(No.YJ2018-9)
文摘There are many strategies to maintain the excellent photoluminescence(PL) characteristics of perovskite quantum dots(QDs). Here, we proposed a facile and effective method to prepare cyan CsPb(Cl/Br)3/SiO2 nanospheres at room temperature. Cubic CsPb(Cl/Br)3 was obtained by adding a LiCl-H2O solution and anion exchange reaction. With(3-aminopropyl)triethoxysilane as an auxiliary agent, a QDs/SiO2 composite was extracted from a sol-gel solution by precipitate-encapsulation method. The transmission electron microscopy images and Fourier transform infrared spectra indicated the QDs were indeed embedded in silica substances.Besides, humidity stability and thermal stability show the composite possesses a great application value.Finally, cyan QDs@SiO2 powder has a high PL quantum yield of up to 84%;the stable cyan fluorescent powder does have great potential to play a key role in commercial full spectrum display.
基金We are grateful for financial support from the National Natural Science Foundation of China(Nos.21772161 and 21622204)the Natural Science Foundation of Fujian Province of China(No.2019J02001)+1 种基金the President Research Funds from Xiamen University(No.20720180036)NFFTBS(No.J1310024),PCSIRT,and Science&Technology Cooperation Program of Xiamen(No.3502Z20183015).
文摘Summary of main observation and conclusion An efficient copper-catalyzed carbocyclization of silyl enol ether tethered ynamides has been developed,allowing rapid and practical construction of diverse 2-azabicyclo[3.2.0]compounds in generally good to excellent yields with broad substrate scope under mild reaction conditions.Importantly,this protocol not only constitutes a rare example of non-noble metal-catalyzed alkyne carbocyclization,but also represents a rare cyclization on the B-position ofπu-tethered ynamides.The possibility of asymmetric carbocyclization via kinetic resolution also emerges.
基金The authors acknowledge the support from National Natural Science Foundation of China(Grant Nos.51902061,52072272,62090031).
文摘Two-dimensional(2D)metal oxide α-MoO_(3) shows great potentials because of its very high dielectric constant,air stability and anisotropic phonon polaritons.However,a method to produce ultrathin single crystallineα-MoO_(3) with high transferability for functional device architecture is lacking.Herein,we report on the controllable synthesis of ultrathinα-MoO_(3) single crystals via chemical vapor deposition(CVD)assisted by plasma pretreatment.We also carried out systematic computational work to explicate the mechanism for the slantly-oriented growth of thin nanosheets on plasma-pretreated substrate.The method possesses certain universality to synthesize other ultrathin oxide materials,such as Bi_(2)O_(3) and Sb_(2)O_(3) nanosheets.As-grownα-MoO_(3) presents a high dielectric constant(≈40),ultrathin thickness(≈3 nm)and high transferability.Memristors withα-MoO_(3) as the functional layers show excellent performance featuring high on/off ratio of approximately 104,much lower set voltage around 0.5 V,and highly repetitive voltage sweep endurance.The power consumption of MoO_(3) memristors is significantly reduced,resulted from reduced thickness of the MoO_(3) nanosheets.Single crystal ultrathinα-MoO_(3) shows great potentials in post-Moore memristor and the synthesis of CVD assisted by plasma pretreatment approach points to a new route for materials growth.
基金Shuguang Program,Grant/Award Number:18SG20Fundamental Research Funds for the Central Universities+2 种基金Shanghai Municipal Education CommissionShanghai Education Development FoundationNational Natural Science Foundation of China,Grant/Award Number:61822405。
文摘Flexible photodetectors(FPDs)have been receiving increasing attention in recent years because of their potential applications in electronic eyes,bioinspired sensing,smart textiles,and wearable devices.Moreover,metal halide perovskites(MHPs)with outstanding optical and electrical properties,good mechanical flexibility,lowcost and low-temperature solution-processed fabrication have become promising candidates as light harvesting materials in FPDs.Herein,we comprehensively review the developments of FPDs based on MHPs reported recently.This review firstly provides an introduction with respect to the performance parameters and device configurations of perovskite photodetectors,followed by the specific requirements of FPDs including substrate and electrode materials.Next,chemical compositions,structures and preparation methods of MHPs are presented.Then,the FPDs on the basis of single-component perovskite and hybrid structure perovskite are discussed,subsequently,self-powered flexible perovskite photodetectors were presented.In the end,conclusions and challenges are put forward in the field of FPDs based on perovskites.
基金This work was supported by the National Key Research and Development Program of China(Nos.2018YFA0208600,2018YFA0704502)the National Natural Science Foundation of China(Nos.21871263,22071245,22033008)+1 种基金the Fund of the Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZZ103)the Project of the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y201850).
文摘Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and environmental friendliness. In this work, we prepared a series of boron-doped covalent triazine frameworks and found that boron doping can significantly improve the CO selectivity up to 91.2% in the CO_(2) electroreduction reactions(CO_(2)RR). The effect of different doping ratios on the activity by adjusting the proportion of doped atoms was systematically investigated. This work proves that the doping modification of non-metallic materials is a very effective way to improve their activity, and also lays a foundation for the study of other element doping in the coming future.
基金supported by the National Natural Science Foundation of China(21772161,21828102)the Natural Science Foundation of Fujian Province(2019J02001)+3 种基金the President Research Funds from Xiamen University(20720180036)NFFTBS(J1310024)the Foundation of Wenzhou Science&Technology Bureau(ZY2020027)the Science&Technology Co-operation Program of Xiamen(3502Z20183015)。
文摘Direct functionalization of inert C(sp^(3))–H bonds is a topic of immense contemporary interest and exceptional value in organic synthesis.The recent research has established a novel and practical protocol which features the engagement of vinyl cation species to functionalize C(sp^(3))–H bonds.The discussion of the topic is arranged by the strategies to generate the reactive intermediates,including ionization of vinyl triflates,addition of electrophiles to alkynes,tandem cyclization of enynes or diynes,and decomposition ofβ-hydroxy-α-diazo ketones.This review closes with a personal perspective on the dynamic research area of unactivated C(sp^(3))–H functionalization via vinyl cations.Hopefully,it will provide timely illumination and beneficial guidance for organic chemists who are interested in this area.Meanwhile continued development of the field is strongly anticipated in the future.
