The combination of a powerful CO_(2)-enriching carrier and robust active component provides a new idea for the construction of efficient catalysts for electrocatalytic CO_(2)reduction.Herein,novel perforated nitrogen-...The combination of a powerful CO_(2)-enriching carrier and robust active component provides a new idea for the construction of efficient catalysts for electrocatalytic CO_(2)reduction.Herein,novel perforated nitrogen-rich graphene-like carbon nanolayers(PNGC)are prepared from biomass derivatives,which promotes the oriented deposition of In-doped Cu_(2)(OH)_(3)(NO_(3))nanosheet patches.A robust Cu-In/PNGC composite catalyst is then obtained via simple in-situ electrochemical reduction.Unsurprisingly,CuIn/PNGC exhibits a CO Faradaic efficiency(FECO)of 91.3%and a remarkable CO partial current density(jCO)of 136.4 m A cm^(-2)at a moderate overpotential of 0.59 V for electrocatalytic CO_(2)reduction reaction(CO_(2)RR).DFT calculations and experimental studies indicate that the strong carrier effect of PNGC makes PNGC carried Cu-In nanosheets improved the adsorption capacity of CO_(2)gas,reconfigured electronic structure,and reduced free energy of key intermediate formation,thereby the CO_(2)activation and conversion are promoted.展开更多
In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues fr...In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues from acid hydrolysis were collected for producing cellulose nanofibrils(CNF) via post high-pressure homogenization. Citric acid could be easily recovered after hydrolysis reactions through crystallization due to its low water solubility or through precipitation as a calcium salt followed by acidification. Several important properties of CNC and CNF, such as dimension, crystallinity, surface chemistry, thermal stability, were evaluated. Results showed that the obtained CNC and CNF surfaces contained carboxylic acid groups that facilitated functionalization and dispersion in aqueous processing. The recyclability of citric acid and the carboxylated CNC/CNF give the renewable cellulose nanomaterial huge potential for a wide range of industrial applications. Furthermore, the resultant CNC and CNF were used as reinforcing agents to make sodium carboxymethyl cellulose(CMC) films. Both CNC and CNF showed reinforcing effects in CMC composite films. The tensile strength of CMC films increased by 54.3% and 85.7% with 10 wt% inclusion of CNC and CNF, respectively. This study provides detailed information on carboxylated nanocellulose prepared by critic acid hydrolysis; a sustainable approach for the preparation of CNC/CNF is of significant importance for their various uses.展开更多
In this study, the characteristics of nanocellulose extracted from bleached softwood and hardwood pulps by formic acid hydrolysis followed by TEMPO-mediated oxidation were compared using transmission electron microsco...In this study, the characteristics of nanocellulose extracted from bleached softwood and hardwood pulps by formic acid hydrolysis followed by TEMPO-mediated oxidation were compared using transmission electron microscopy(TEM), atomic force microscopy(AFM), Fourier transform infrared analysis(FT-IR), X-ray diffraction(XRD), and thermal gravimetric analysis(TGA). The experimental results showed that the nanocellulose products derived from spruce pulp exhibited a relatively larger particle size, higher crystallinity, and higher thermal stability, compared with the corresponding products obtained from aspen pulp under the same conditions.Furthermore, the study helped establish that the properties of the nanocellulose products were highly dependent on the nature of the starting materials under identical processing conditions.展开更多
The power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (P061BM) based organic solar cells (OSCs) is significantly improved by using benzyl aceta...The power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (P061BM) based organic solar cells (OSCs) is significantly improved by using benzyl acetate (BA), an organic compound without any halogen or sulphur atom, as a processing additive to control the blend morphology. The solar cells show PCE of 3.85% with a fill factor (FF) of 65.22%, which are higher than those of the common thermal annealing device (PCE 3.30%, FF 60.83%). The overall increased PCE depends upon the enhanced crystallinity of P3HT and good carriers transport, with a high balanced charge carrier mobility.展开更多
The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and ...The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and an understanding of how solvent additives affect OSCs is currently limited.In this study,we developed an in situ grazing incidence wide-angle X-ray scattering(GIWAXS)technique in the SAXS beamline(BL16 B1)at the Shanghai Synchrotron Radiation Facility,and the additive effects of1,8-diiodoctane(DIO)on the performance and morphology evolution of the PTB7-Th/PC71 BM device was investigated in depth.The results revealed that the crystal size increased with the volume ratio of DIO,and a drastic evolution of lattice space and crystal coherence length was observed during thermal annealing for the first time,to our knowledge.The discrete PC71BM molecules dissolved by DIO have an effect similar to that of the nucleating agent for PTB7-Th,boosting the crystallization of PTB7-Th,reducing phase separation,and inducing more drastic morphological evolution during thermal annealing.Our results provide a deep perspective for the mechanism of solvent additives,while also showing the significance and feasibility of the in situ GIWAXS technique we developed at BL16 B1.展开更多
Photocatalytic oxidation coupling of amines represents a green and cost-effective method for the synthesis of highly value-added imines under visible light irradiation.However,the catalytic efficiency was severely lim...Photocatalytic oxidation coupling of amines represents a green and cost-effective method for the synthesis of highly value-added imines under visible light irradiation.However,the catalytic efficiency was severely limited by poor visible light response and easy recombination of photogenerated charge carriers.Herein,we report a g-CgN_(4)/α-Bi_(2)O_(3)Z-scheme heterojunction via electrostatic self-assembly of g-C_(3)N_(4)nanosheets and oxygen-va-cancy-rich aα-Bi_(2)O_(3)microsphere for visible-light driven oxidative coupling of amines to imines in H_(2)0 as green solvent at room temperature.Amines with diverse functional groups were efficiently converted into the corre-sponding imines in good to excellent yields.Impressively,this photocatalytic protocol is applicable for the challenging hetero-coupling of two structurally different amines to construct complicated asymmetric imines,which is the first report of photocatalytic hetero-coupling of amines to imines to our knowledge.Furthermore,the Z-scheme heterojunction also demonstrated high stability and could be readily separated and reused without obvious decay in activity and selectivity.Comprehensive characterizations and control experiments reveal the construction of Z-scheme heterojunction with intimate interface between g-CgN4 and a-Bi_(2)O_(3)greatly boosts the transfer and separation of photogenerated charge carries and enhances the redox capability.Meanwhile,the surface oxygen vacancies in a-Biz_(2)O_(3)also benefits the separation of photogenerated charge carriers and acti-vation of reactants.These jointly contributed to an enhanced photocatalytic performance for oxidative coupling of amines to imines.展开更多
Two dimensional (2D) nanocrystals of noble metals (e.g., Au, Ag, Pt) often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedi- c...Two dimensional (2D) nanocrystals of noble metals (e.g., Au, Ag, Pt) often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedi- cines. In recent years, there has been a focus on discovering the fundamental mechanisms which govern the synthesis of the diverse geometries of these 2D metal nanocrystals (e.g., shapes, thickness, and lateral sizes). This has resulted in being able to better control the properties of these 2D structures for specific applications. In this review, a brief historical survey of the intrinsic anisotropic properties and quantum size effects of 2D noble metal nanocrystals is given and then a summary of synthetic approaches to control their shapes and sizes is presented. The unique properties and fascinating applica- tions of these nanocrystals are also discussed.展开更多
A new star-shaped small molecule named TCNR3TTPA,with a triphenylamine(TPA)unit as the central building block and2-(1,1-dicyanomethylene)-3-octyl rhodanine(CNR)as the end-capped group,has been designed and synthesized...A new star-shaped small molecule named TCNR3TTPA,with a triphenylamine(TPA)unit as the central building block and2-(1,1-dicyanomethylene)-3-octyl rhodanine(CNR)as the end-capped group,has been designed and synthesized.TCNR3TTPA showed a deep highest occupied molecular orbital(HOMO)energy level( 5.60 e V)and broad absorption.The solution-processed bulk heterojunction(BHJ)solar cells based on TCNR3TTPA:PC61BM(1:1,w/w)exhibited a high open-circuit voltage(Voc)of 0.99 V,a short-circuit current density(Jsc)of 5.76 m A/cm2,and a power conversion efficiency(PCE)of 2.50%under the illumination of AM 1.5 G,100 m W/cm2.The high Voc is ascribed to the strong electron-with-drawing ability of the end-capped 2-(1,1-dicyanomethylene)-3-octyl rhodanine group.These results demonstrated that the Voc of small-molecule organic solar cells could be increased by introducing a strong electron-withdrawing end-capped block,and that this is an effective strategy to design high-performance small molecules for organic solar cells.展开更多
Herein,we report a novel heterogeneous photocatalyst for radical-mediated oxidative oxysulfonylation of alkynes toβ-keto sulfones under environmentally benign conditions.The oxygen vacancy-rich semiconductor Nb2O5(la...Herein,we report a novel heterogeneous photocatalyst for radical-mediated oxidative oxysulfonylation of alkynes toβ-keto sulfones under environmentally benign conditions.The oxygen vacancy-rich semiconductor Nb2O5(labeled as OVs-N-Nb_(2)O_(5))could efficiently catalyze a wide range of alkynes,especially for those bearing electron-deficient substituents or internal alkynes,to their correspondingβ-keto sulfones in good to high yields with good tolerance of diverse functional groups under visible-light illumination.The late-stage modification of steroidal compounds and synthesis of bioactive molecules were also achieved via this procedure,highlighting its potential for practical applications.Meanwhile,the photocatalyst OVs-N-Nb_(2)O_(5) showed outstanding catalytic stability for successive recycles without appreciable loss in activity and selectivity.The critical role of oxygen vacancies on improving reaction activity and selectivity was clearly disclosed via control experiments and theoretical calculation.展开更多
Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels.In this work,corn stover was pretreated with a novel modified alkali process(NaOH+anthra...Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels.In this work,corn stover was pretreated with a novel modified alkali process(NaOH+anthraquinone(AQ)+sodium lignosulfonate(SLS)),and then enzymatically hydrolyzed with an enzyme cocktail(cellulase(Celluclast 1.5L),β-glucosidase(Novozyme 188)and xylanase(from thermomyceslanuginosus))in the pH range of 4.0-6.5.It was found that the suitable pH for the enzymatic saccharification process to achieve a high glucan yield was between 4.2 and 5.7,while the appropriate pH to obtain a high xylan yield was in the range of 4.0-4.7.The best pH for the enzymatic saccharification process was found to be 4.4 in terms of the final total sugar yield,as xylanase worked most efficiently in the pH range of 4.0-4.7,under the conditions in the study.The addition of xylanase in the enzymatic saccharification process could hydrolyze xylan in the substrates and reduce the nonspecific binding of cellulase,thus improving the total sugar yields.展开更多
In this work,a sustainable method to prepare functional cellulose nanocrystals(CNCs)and cellulose nanofibrils(CNFs)using formic acid(FA)(a recoverable organic acid)was established.After FA hydrolysis,the obtained CNCs...In this work,a sustainable method to prepare functional cellulose nanocrystals(CNCs)and cellulose nanofibrils(CNFs)using formic acid(FA)(a recoverable organic acid)was established.After FA hydrolysis,the obtained CNCs could be well dispersed in DMAC.Thus,the CNC products and fibrous cellulosic solid residue(FCSR)in DMAC could be easily separated by a conventional centrifugal process,and the collected FCSR could be further fibrillated to CNFs with relatively low-intensity mechanical fibrillation process.The isolated CNC products showed high crystallinity index(about 75%)and excellent thermal stability(with onset thermal degradation temperature of 325℃).Both the resultant CNCs and CNFs showed better dispersibility in DMSO,DMF and DMAC respectively because of the introduction of ester groups on the surface of the products.The presence of surface ester groups could increase the interface compatibility of nanocelluloses with polymeric matrices and enable their applications in reinforcing polymeric matrix materials(e.g.the composite films like PHVB+CNFs).展开更多
This paper examined different kinds of organic functional groups that were introduced onto the surface of nano TiO_(2) by surface modification with different types of zircoaluminate coupling agents.The modified nanoTi...This paper examined different kinds of organic functional groups that were introduced onto the surface of nano TiO_(2) by surface modification with different types of zircoaluminate coupling agents.The modified nanoTiO_(2) products with different interfacial properties were obtained,and the impact of the interfacial properties of nanoTiO_(2) on the rheological behavior of paper coating and the properties of coated paper was systematically investigated.The steady shear rheological results showed that the paper coatings containing nano TiO_(2) exhibited a pseudoplastic fluid behavior,characterized as obvious shear thinning.Compared to the hydrophilic unmodified nano TiO_(2),modified nano TiO_(2) could contribute more to the viscosity of paper coatings.The study on the dynamic viscoelasticity revealed that,through the enhancing action among each component in paper coatings,the modified nano TiO_(2) with quaternary amine groups or carboxyl led to a higher dynamic elastic storage modulus and viscous loss modulus of paper coatings.In addition,SEM and AFM analyses indicated that adding modified nano TiO_(2) products in paper coating could improve the coating structure,thus ameliorating the optical properties and printability of coated paper.The results obtained could provide a good reference for the application of nano pigments in paper coating.展开更多
Pretreatment and fractionation are amongst the key steps for the conversion of lignocelluloses to sustainable biofuels,biomaterials or biochemicals,as pretreatment/fractionation can break the natural recalcitrance of ...Pretreatment and fractionation are amongst the key steps for the conversion of lignocelluloses to sustainable biofuels,biomaterials or biochemicals,as pretreatment/fractionation can break the natural recalcitrance of lignocelluloses,improving the conversion efficiency of downstream processes.This paper reviews the recent progress on the pretreatment and fractionation of lignocelluloses for biorefinery at the Chinese Academy of Sciences-Qingdao Institute of Bioenergy and Bioprocess Technology(QIBEBT).The main technologies developed at the QIBEBT in recent years include alkaline twin-screw extrusion pretreatment,modified alkali pretreatment,hydrogen peroxide-assisted sodium carbonate pretreatment,fractionation with formic acid,as well as the two-step fractionation by hot water treatment coupling ammonium sulfite treatment.With the development of these technologies,a pilot scale platform for the pretreatment and saccharification of biomass has been established in the pilot plant of QIBEBT.展开更多
To clearly show how important the impact of side chains on organic solar cells(OSCs)is,we designed three acceptors IDIC-CxPh(x=4,5,or 6)via subtle side-chain regulation.Despite this small change,significant distinctio...To clearly show how important the impact of side chains on organic solar cells(OSCs)is,we designed three acceptors IDIC-CxPh(x=4,5,or 6)via subtle side-chain regulation.Despite this small change,significant distinctions were detected.IDIC-C4Ph devices achieve an optimal efficiency of 13.94%under thermal annealing,but thermal-assistant solvent-vapor annealing hugely suppresses the efficiencies to 10%.However,the C6Ph side chain endows extremely disordered stacking orientations,generating moderate efficiencies of~12.50%.Excitingly,the IDIC-C5Ph affords an unexpected two-channel p-p charge transport(TCCT)property,boosting the fill factor(FF)by up to 80.02%and efficiency to 14.56%,ranking the best among five-ring fused-ladder-type acceptors.Impressively,the special TCCT behavior of IDIC-C5Ph enables 470 nm thick-film OSC with a high FF of up to 70.12%and efficiency of 13.01%,demonstrating the great promise in fabricating largescale OSCs.展开更多
基金supported by the National Natural Science Foundation of China(U21B2099)。
文摘The combination of a powerful CO_(2)-enriching carrier and robust active component provides a new idea for the construction of efficient catalysts for electrocatalytic CO_(2)reduction.Herein,novel perforated nitrogen-rich graphene-like carbon nanolayers(PNGC)are prepared from biomass derivatives,which promotes the oriented deposition of In-doped Cu_(2)(OH)_(3)(NO_(3))nanosheet patches.A robust Cu-In/PNGC composite catalyst is then obtained via simple in-situ electrochemical reduction.Unsurprisingly,CuIn/PNGC exhibits a CO Faradaic efficiency(FECO)of 91.3%and a remarkable CO partial current density(jCO)of 136.4 m A cm^(-2)at a moderate overpotential of 0.59 V for electrocatalytic CO_(2)reduction reaction(CO_(2)RR).DFT calculations and experimental studies indicate that the strong carrier effect of PNGC makes PNGC carried Cu-In nanosheets improved the adsorption capacity of CO_(2)gas,reconfigured electronic structure,and reduced free energy of key intermediate formation,thereby the CO_(2)activation and conversion are promoted.
基金financial support for this work is from the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(No.2015BAD14B06)the National Natural Science Foundation of China(No.31470609,No.25106240 and No.21433001)+1 种基金the Primary Research and Development Plan of Shandong Province(No.2016GGX104003 and No.2016CYJS07A02)the Young Taishan Scholars Program of Shandong Province(No.tsqn20161052)
文摘In this study, cellulose nanocrystals(CNC) with surface carboxylic groups were prepared from bleached softwood pulp by hydrolysis with concentrated citric acid at concentrations of 60 wt%~80 wt%. The solid residues from acid hydrolysis were collected for producing cellulose nanofibrils(CNF) via post high-pressure homogenization. Citric acid could be easily recovered after hydrolysis reactions through crystallization due to its low water solubility or through precipitation as a calcium salt followed by acidification. Several important properties of CNC and CNF, such as dimension, crystallinity, surface chemistry, thermal stability, were evaluated. Results showed that the obtained CNC and CNF surfaces contained carboxylic acid groups that facilitated functionalization and dispersion in aqueous processing. The recyclability of citric acid and the carboxylated CNC/CNF give the renewable cellulose nanomaterial huge potential for a wide range of industrial applications. Furthermore, the resultant CNC and CNF were used as reinforcing agents to make sodium carboxymethyl cellulose(CMC) films. Both CNC and CNF showed reinforcing effects in CMC composite films. The tensile strength of CMC films increased by 54.3% and 85.7% with 10 wt% inclusion of CNC and CNF, respectively. This study provides detailed information on carboxylated nanocellulose prepared by critic acid hydrolysis; a sustainable approach for the preparation of CNC/CNF is of significant importance for their various uses.
基金the Johan GadolinScholarship Programme at the Johan Gadolin Process Chemistry Centre at Abo Akademi University (Finland)the National Natural Science Foundation of China (No. 31470609)
文摘In this study, the characteristics of nanocellulose extracted from bleached softwood and hardwood pulps by formic acid hydrolysis followed by TEMPO-mediated oxidation were compared using transmission electron microscopy(TEM), atomic force microscopy(AFM), Fourier transform infrared analysis(FT-IR), X-ray diffraction(XRD), and thermal gravimetric analysis(TGA). The experimental results showed that the nanocellulose products derived from spruce pulp exhibited a relatively larger particle size, higher crystallinity, and higher thermal stability, compared with the corresponding products obtained from aspen pulp under the same conditions.Furthermore, the study helped establish that the properties of the nanocellulose products were highly dependent on the nature of the starting materials under identical processing conditions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61405209,61107090,21172187,51273168,20102139 and 51173199the National Basic Research Program of China under Grant Nos 2014CB643501 and 2010DFA52310+3 种基金the Shandong Provincial Natural Science Foundation under Grant No ZR2011BZ007the Key Project of Hunan Province Education Department under Grant No 13A102the Innovation Group and Xiangtan Joint Project of Hunan Natural Science Foundation under Grant Nos 12JJ7002 and 12JJ8001the Scientific Research Fund of Hunan Provincial Education Department under Grant Nos 11CY023 and 12B123
文摘The power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (P061BM) based organic solar cells (OSCs) is significantly improved by using benzyl acetate (BA), an organic compound without any halogen or sulphur atom, as a processing additive to control the blend morphology. The solar cells show PCE of 3.85% with a fill factor (FF) of 65.22%, which are higher than those of the common thermal annealing device (PCE 3.30%, FF 60.83%). The overall increased PCE depends upon the enhanced crystallinity of P3HT and good carriers transport, with a high balanced charge carrier mobility.
基金supported by the National Natural Science Foundation of China(Nos.U1932118,2005324)the National Key R&D Program of China(Nos.2017YFA0403002,2018YFB0704201)。
文摘The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and an understanding of how solvent additives affect OSCs is currently limited.In this study,we developed an in situ grazing incidence wide-angle X-ray scattering(GIWAXS)technique in the SAXS beamline(BL16 B1)at the Shanghai Synchrotron Radiation Facility,and the additive effects of1,8-diiodoctane(DIO)on the performance and morphology evolution of the PTB7-Th/PC71 BM device was investigated in depth.The results revealed that the crystal size increased with the volume ratio of DIO,and a drastic evolution of lattice space and crystal coherence length was observed during thermal annealing for the first time,to our knowledge.The discrete PC71BM molecules dissolved by DIO have an effect similar to that of the nucleating agent for PTB7-Th,boosting the crystallization of PTB7-Th,reducing phase separation,and inducing more drastic morphological evolution during thermal annealing.Our results provide a deep perspective for the mechanism of solvent additives,while also showing the significance and feasibility of the in situ GIWAXS technique we developed at BL16 B1.
基金supported by the National Natural Science Foundation of China(No.22078350)the Natural Science Foundation of Shandong Province(ZR2020KB016)Shandong Energy Institute Fund(Grant no.SEII202138).
文摘Photocatalytic oxidation coupling of amines represents a green and cost-effective method for the synthesis of highly value-added imines under visible light irradiation.However,the catalytic efficiency was severely limited by poor visible light response and easy recombination of photogenerated charge carriers.Herein,we report a g-CgN_(4)/α-Bi_(2)O_(3)Z-scheme heterojunction via electrostatic self-assembly of g-C_(3)N_(4)nanosheets and oxygen-va-cancy-rich aα-Bi_(2)O_(3)microsphere for visible-light driven oxidative coupling of amines to imines in H_(2)0 as green solvent at room temperature.Amines with diverse functional groups were efficiently converted into the corre-sponding imines in good to excellent yields.Impressively,this photocatalytic protocol is applicable for the challenging hetero-coupling of two structurally different amines to construct complicated asymmetric imines,which is the first report of photocatalytic hetero-coupling of amines to imines to our knowledge.Furthermore,the Z-scheme heterojunction also demonstrated high stability and could be readily separated and reused without obvious decay in activity and selectivity.Comprehensive characterizations and control experiments reveal the construction of Z-scheme heterojunction with intimate interface between g-CgN4 and a-Bi_(2)O_(3)greatly boosts the transfer and separation of photogenerated charge carries and enhances the redox capability.Meanwhile,the surface oxygen vacancies in a-Biz_(2)O_(3)also benefits the separation of photogenerated charge carriers and acti-vation of reactants.These jointly contributed to an enhanced photocatalytic performance for oxidative coupling of amines to imines.
基金Acknowledgements National Key Technology R&D Program of the Ministry of Science and Technology (No. 2015BADI4B06), National Natural Science Foundation of China (Grant No. 21474125), Shandong Collaborative Innovation Center for Marine Biomass Fiber Materials and Textiles and Chinese "1000 Youth Talent Program" are kindly acknowledged for financial support.
文摘Two dimensional (2D) nanocrystals of noble metals (e.g., Au, Ag, Pt) often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedi- cines. In recent years, there has been a focus on discovering the fundamental mechanisms which govern the synthesis of the diverse geometries of these 2D metal nanocrystals (e.g., shapes, thickness, and lateral sizes). This has resulted in being able to better control the properties of these 2D structures for specific applications. In this review, a brief historical survey of the intrinsic anisotropic properties and quantum size effects of 2D noble metal nanocrystals is given and then a summary of synthetic approaches to control their shapes and sizes is presented. The unique properties and fascinating applica- tions of these nanocrystals are also discussed.
基金supported by the National Natural Science Foundation of China(51173199,51211140346,61405209)the National Basic Research Program of China(2014CB643501,2010DFA52310)+1 种基金the Shandong Provincial Natural Science Foundation(ZR2011BZ007)the Qingdao Municipal Science and Technology Program(11-2-4-22-hz)
文摘A new star-shaped small molecule named TCNR3TTPA,with a triphenylamine(TPA)unit as the central building block and2-(1,1-dicyanomethylene)-3-octyl rhodanine(CNR)as the end-capped group,has been designed and synthesized.TCNR3TTPA showed a deep highest occupied molecular orbital(HOMO)energy level( 5.60 e V)and broad absorption.The solution-processed bulk heterojunction(BHJ)solar cells based on TCNR3TTPA:PC61BM(1:1,w/w)exhibited a high open-circuit voltage(Voc)of 0.99 V,a short-circuit current density(Jsc)of 5.76 m A/cm2,and a power conversion efficiency(PCE)of 2.50%under the illumination of AM 1.5 G,100 m W/cm2.The high Voc is ascribed to the strong electron-with-drawing ability of the end-capped 2-(1,1-dicyanomethylene)-3-octyl rhodanine group.These results demonstrated that the Voc of small-molecule organic solar cells could be increased by introducing a strong electron-withdrawing end-capped block,and that this is an effective strategy to design high-performance small molecules for organic solar cells.
基金supportof the National Natural Science Foundation of China(Nos.22002178,22078350)the Natural Science Foundation of Shandong Province(ZR2020KB016)+1 种基金Shandong Energy Institute Fund(Grant No.SEll202138)Y.Y.alsothanks the Royal Society(UK)fora Newton Advanced Fellowship(NAF/R2/180695).
文摘Herein,we report a novel heterogeneous photocatalyst for radical-mediated oxidative oxysulfonylation of alkynes toβ-keto sulfones under environmentally benign conditions.The oxygen vacancy-rich semiconductor Nb2O5(labeled as OVs-N-Nb_(2)O_(5))could efficiently catalyze a wide range of alkynes,especially for those bearing electron-deficient substituents or internal alkynes,to their correspondingβ-keto sulfones in good to high yields with good tolerance of diverse functional groups under visible-light illumination.The late-stage modification of steroidal compounds and synthesis of bioactive molecules were also achieved via this procedure,highlighting its potential for practical applications.Meanwhile,the photocatalyst OVs-N-Nb_(2)O_(5) showed outstanding catalytic stability for successive recycles without appreciable loss in activity and selectivity.The critical role of oxygen vacancies on improving reaction activity and selectivity was clearly disclosed via control experiments and theoretical calculation.
基金The authors are grateful for the great support of research funding from Procter and Gamble Co.This work was also partially supported by the National Natural Science Foundation of China(Grant No.31370582,Grant No.21306216,and Grant No.31470609)Shandong Provincial Natural Science Foundation for Distinguished Young Scholar(China)(Grant No.JQ201305)as well as the National High Technology Research and Development Program(“863”program)of China(Grant No.2012AA022301).
文摘Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels.In this work,corn stover was pretreated with a novel modified alkali process(NaOH+anthraquinone(AQ)+sodium lignosulfonate(SLS)),and then enzymatically hydrolyzed with an enzyme cocktail(cellulase(Celluclast 1.5L),β-glucosidase(Novozyme 188)and xylanase(from thermomyceslanuginosus))in the pH range of 4.0-6.5.It was found that the suitable pH for the enzymatic saccharification process to achieve a high glucan yield was between 4.2 and 5.7,while the appropriate pH to obtain a high xylan yield was in the range of 4.0-4.7.The best pH for the enzymatic saccharification process was found to be 4.4 in terms of the final total sugar yield,as xylanase worked most efficiently in the pH range of 4.0-4.7,under the conditions in the study.The addition of xylanase in the enzymatic saccharification process could hydrolyze xylan in the substrates and reduce the nonspecific binding of cellulase,thus improving the total sugar yields.
基金supported by the National Natural Science Foundation of China (contract grant numbers:21306261,31470609,and 25106240)Primary Research and Development Plan of Shandong Province (contract grant numbers:2016GGX104003,and 2016CYJS07A02).
文摘In this work,a sustainable method to prepare functional cellulose nanocrystals(CNCs)and cellulose nanofibrils(CNFs)using formic acid(FA)(a recoverable organic acid)was established.After FA hydrolysis,the obtained CNCs could be well dispersed in DMAC.Thus,the CNC products and fibrous cellulosic solid residue(FCSR)in DMAC could be easily separated by a conventional centrifugal process,and the collected FCSR could be further fibrillated to CNFs with relatively low-intensity mechanical fibrillation process.The isolated CNC products showed high crystallinity index(about 75%)and excellent thermal stability(with onset thermal degradation temperature of 325℃).Both the resultant CNCs and CNFs showed better dispersibility in DMSO,DMF and DMAC respectively because of the introduction of ester groups on the surface of the products.The presence of surface ester groups could increase the interface compatibility of nanocelluloses with polymeric matrices and enable their applications in reinforcing polymeric matrix materials(e.g.the composite films like PHVB+CNFs).
基金The authors extend a sincere acknowledge and appreciation for the financial support from the National Natural Science Foundation of China(Grant No.21306216,and Grant No.31470609)。
文摘This paper examined different kinds of organic functional groups that were introduced onto the surface of nano TiO_(2) by surface modification with different types of zircoaluminate coupling agents.The modified nanoTiO_(2) products with different interfacial properties were obtained,and the impact of the interfacial properties of nanoTiO_(2) on the rheological behavior of paper coating and the properties of coated paper was systematically investigated.The steady shear rheological results showed that the paper coatings containing nano TiO_(2) exhibited a pseudoplastic fluid behavior,characterized as obvious shear thinning.Compared to the hydrophilic unmodified nano TiO_(2),modified nano TiO_(2) could contribute more to the viscosity of paper coatings.The study on the dynamic viscoelasticity revealed that,through the enhancing action among each component in paper coatings,the modified nano TiO_(2) with quaternary amine groups or carboxyl led to a higher dynamic elastic storage modulus and viscous loss modulus of paper coatings.In addition,SEM and AFM analyses indicated that adding modified nano TiO_(2) products in paper coating could improve the coating structure,thus ameliorating the optical properties and printability of coated paper.The results obtained could provide a good reference for the application of nano pigments in paper coating.
基金supported by the National Natural Science Foundation of China (contract grant numbers:21306261,31470609,25106240)the Primary Research and Development Plan of Shandong Province (contract grant numbers:2016GGX104003,and 2016CYJS07A02).
文摘Pretreatment and fractionation are amongst the key steps for the conversion of lignocelluloses to sustainable biofuels,biomaterials or biochemicals,as pretreatment/fractionation can break the natural recalcitrance of lignocelluloses,improving the conversion efficiency of downstream processes.This paper reviews the recent progress on the pretreatment and fractionation of lignocelluloses for biorefinery at the Chinese Academy of Sciences-Qingdao Institute of Bioenergy and Bioprocess Technology(QIBEBT).The main technologies developed at the QIBEBT in recent years include alkaline twin-screw extrusion pretreatment,modified alkali pretreatment,hydrogen peroxide-assisted sodium carbonate pretreatment,fractionation with formic acid,as well as the two-step fractionation by hot water treatment coupling ammonium sulfite treatment.With the development of these technologies,a pilot scale platform for the pretreatment and saccharification of biomass has been established in the pilot plant of QIBEBT.
基金The authors are deeply grateful to the National Natural Science Foundation of China(21502205,51773220,51703104,and 51873227)DICP&QIBEBT(UN201805)for financial support.X.C.B.deeply thanks the Youth Innovation Promotion Association CAS(2016194).R.Q.Y.gives thanks to the“Chutian Scholar Program”of Hubei province.The work is also supported by the Dalian National Laboratory for Clean Energy for Clean Energy(DNL),CAS.The authors thanks Prof.Chunming Yang from the Shanghai Synchrotron Radiation Facility for useful discussions.
文摘To clearly show how important the impact of side chains on organic solar cells(OSCs)is,we designed three acceptors IDIC-CxPh(x=4,5,or 6)via subtle side-chain regulation.Despite this small change,significant distinctions were detected.IDIC-C4Ph devices achieve an optimal efficiency of 13.94%under thermal annealing,but thermal-assistant solvent-vapor annealing hugely suppresses the efficiencies to 10%.However,the C6Ph side chain endows extremely disordered stacking orientations,generating moderate efficiencies of~12.50%.Excitingly,the IDIC-C5Ph affords an unexpected two-channel p-p charge transport(TCCT)property,boosting the fill factor(FF)by up to 80.02%and efficiency to 14.56%,ranking the best among five-ring fused-ladder-type acceptors.Impressively,the special TCCT behavior of IDIC-C5Ph enables 470 nm thick-film OSC with a high FF of up to 70.12%and efficiency of 13.01%,demonstrating the great promise in fabricating largescale OSCs.