The electrochemical hydrogenation(ECH)of 5-hydroxymethylfurfural(HMF)to 2,5-dihydroxymethylfuran(DHMF)represents a pivotal pathway for the electrocatalytic upgrading of biomass-based organic small molecules,offering s...The electrochemical hydrogenation(ECH)of 5-hydroxymethylfurfural(HMF)to 2,5-dihydroxymethylfuran(DHMF)represents a pivotal pathway for the electrocatalytic upgrading of biomass-based organic small molecules,offering significant reductions in energy consumption while producing value-added chemicals.The conversion of HMF to DHMF is challenging due to the high reduction potential and complex intermediates of HMF ECH under neutral environment.Also,the total efficiency is hindered by sluggish anodic oxygen evolution reaction(OER)kinetics.Herein,we report a synthesis of highly alloyed Pd-Pt bimetallene(Pd3Pt1 BML)for HMF ECH coupled with formic acid oxidation reaction(FAOR).Through a combination of in-situ Raman spectroscopy,electron paramagnetic resonance analysis,and theoretical calculations,we elucidate that the HMF adsorption on Pd atoms,strategically separated by Pt atoms,is weakened compared to pure Pd surfaces.Additionally,Pt atoms serve as crucial providers of active hydrogen to neighboring Pd atoms,synergistically enhancing the reaction kinetics of HMF conversion with a Faradaic efficiency>93%.Meanwhile,the atomically dispersed Pt atoms endow Pd_(3)Pt_(1) BML with high electrochemical performance for the direct pathway of FAOR at the anode.As a result,a FAOR-assisted HMF ECH system equipped with bifunctional Pd3Pt1 BML achieves the energy-efficient conversion of HMF to DHMF at electrolysis voltage of 0.72 V at 10 mA cm^(–2).This work provides insights into the rational design of bifunctional catalysts featuring two distinct types of active sites for advanced energy electrocatalysis and ECH.展开更多
Nitrene transfer reactions are powerful tools in synthetic organic chemistry.In recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely pursued.Such...Nitrene transfer reactions are powerful tools in synthetic organic chemistry.In recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely pursued.Such species undergoes facile C-H amination,aziridination,and bifunctionalization of alkenes under the catalysis of different transition metals including Rh,Fe,Ru and others,enabling the efficient construction of various nitrogen-containing molecules.In this review,the recent developments in nitrene transfer reactions with carbamates via N-O bond cleavage were introduced based on different types of reaction,and the key mechanistic information and synthetic applications of the methodologies were discussed.展开更多
Developing robust oxygen electrocatalyst with high-performance is very significant for practical rechargeable Zn-air battery.We report herein the preparation of three-dimensional continuous nanocarbon network composed...Developing robust oxygen electrocatalyst with high-performance is very significant for practical rechargeable Zn-air battery.We report herein the preparation of three-dimensional continuous nanocarbon network composed of interconnected nitrogen-doped carbon nanotubes and its application as oxygen electrocatalysis in rechargeable Zn-air battery.Except the excellent electrochemical bifunctionality,this carbon nanotube matrix also delivers an impressive battery performance.Specifically,an opencircuit voltage of 1.50 V as well as a high power density of 220 m W cm^(-2) with remarkable cycling stability for 1600 h is achieved in the rechargeable Zn-air battery.The study not only provides an efficient bifunctional oxygen electrocatalyst but more importantly may pave significant concepts in designing robust electrode for long-life rechargeable Zn-air battery and other energy technologies.展开更多
Electrocatalysts are one of the essential components for the devices of high-efficiency green energy storage and conversion,such as metal-air cells,fuel cells,and water electrolysis systems.While catalysts made from n...Electrocatalysts are one of the essential components for the devices of high-efficiency green energy storage and conversion,such as metal-air cells,fuel cells,and water electrolysis systems.While catalysts made from noble metals possess high catalytic performance in both oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),their scarcity and expensiveness significantly limit large-scale applications.In this regard,metal-free/non-noble metal carbon-based catalysts have become competitive alternatives to replace catalysts made of noble metals.Nevertheless,low catalytic ORR/OER performance is the challenge of carbon-based catalysts for the commercial applications of metal-air batteries.To solve the problem of poor catalytic performance,two strategies have been proposed:(1)controlling the microstructure of the catalysts to expose more active sites as the channels of rapid mass and electron transfer;and(2)reducing the reaction energy barrier by optimizing the electronic structures of the catalysts via surface engineering.Here,we review different types of bifunctional ORR/OER electrocatalysts with the activated surface sites.We focus on how the challenge can be overcome with different methods of material synthesis,structural and surface characterization,performance validation/optimization,to outline the principles of surface modifications behind catalyst designs.In particular,we provide critical analysis in the challenges that we are facing in structural design and surface engineering of bifunctional ORR/OER catalysts and indicate the possible solution for these problems,providing the society with clearer ideas on the practical prospects of noble-metal-free electrocatalysts for their future applications.展开更多
A new propene production route from 1-butene metathesis has been developed on heterogeneous 10WO3/Al2O3-HY catalysts with different HY contents. It is found that the catalysts play bi-functionally first for the isomer...A new propene production route from 1-butene metathesis has been developed on heterogeneous 10WO3/Al2O3-HY catalysts with different HY contents. It is found that the catalysts play bi-functionally first for the isomerization of 1-butene to 2-butene and then for the cross-metathesis between 1-butene and 2-butene to propene and 2-pentene. The combination of HY zeolite and Al2O3 is prerequisite for the production of propene. The propene yield keeps increasing with the HY content in the range of 10-70 wt%, where 10WO3/Al2O3-70HY exhibits the highest propene yield. The MS-H2-TPR and MS-O2-TPO characterizations indicate that the increase of HY content in the catalysts weakens the interaction between W species and supports, whereas enhance the probability of coking on the metal species and acid sites.展开更多
Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the di...Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the difference with the conventional FT/zeolite catalyst have not been investigated.Herein,three one-dimensional SAPO zeolites with diverse micropore sizes were synthesized and assembled with ZnAlO_(x)with spinel structure.It was found that ZnAlO_(x)/SAPO-41 and ZnAlO_(x)/SAPO-11 with medium micropore sizes favored the formation of C_(5)–C_(11)hydrocarbons with a high content of iso-paraffins.The characterizations pointed out that the formation of iso-paraffins over SAPO-11 followed a pore-mouth catalysis mechanism,which means the isomerization of linear hydrocarbons can only take place near the pore mouth region of zeolites.This mechanism only allows the formation of mono-branched iso-paraffins in the C_(5)–C_(11)range,which are less prone to be cracked than their di-branched isomers.A careful comparative analysis between ZnAlO_(x)/SAPO-11 and Co/H-meso-ZSM-5 was also made in terms of product distribution,activity,and stability.展开更多
The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient s...The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient strategy is vitally important for the rechargeable ZAB.In this study,the bimetallic ZIFs-containing electrospun(ES) carbon nanofibers membrane with hierarchically porous structure was prepared by coaxial electrospinning and carbonization process,which was expected to be a bifunctional electrocatalyst for ZABs.Owing to the formed dual single-atomic sites of Co-N_(4) and Zn-N_(4),the obtained ES-Co/ZnCNZIFexhibited the preferable performance toward oxygen reduction reaction(ORR) with E1/2of 0.857 V and JLof 5.52 mA cm^(-2),which were more than Pt/C.Meanwhile,it exhibited a marked oxygen evolution reaction(OER) property with overpotential of 462 mV due to the agglomerated metallic Co nanoparticles.Furthermore,the ZAB based on the ES-Co/Zn-CNZIFcarbon nanofibers membranes delivered peak power density of 215 mW cm^(-2),specific capacity of 802.6 mA h g^(-1),and exceptional cycling stability,far larger than Pt/C+RuO_(2)-based ZABs.A solid-state ZAB based on ES-Co/Zn-CNZIFshowed better flexibility and stability with different bending angles.展开更多
The optimum Mo/[H^+] ratio per unit cell of the active precursors in Mo/HZSM-5 catalysts for methane dehydro-aromatization, measured by1H MAS NMR, was found to be about 1 when adjusting the acid sites by altering eith...The optimum Mo/[H^+] ratio per unit cell of the active precursors in Mo/HZSM-5 catalysts for methane dehydro-aromatization, measured by1H MAS NMR, was found to be about 1 when adjusting the acid sites by altering either the SiO2/Al2O3 ratios or the Mo loading. This implies that a concerted interaction between the Mo species and the Bronsted acid sites probably features the bifunctionality of the Mo/HZSM-5 catalyst. On the other hand, it was found that the driving force for Mo species to move into the HSZM-5 zeolite channels and the interaction between the Mo species and the Bronsted acid sites are closely and proportionably related with the amount of Bronsted acid sites per unit cell.展开更多
The photocatalytic performances of water oxidation were usually carried out in two different systems,photosensitizer and non-photosensitizer systems.There is few report about the same catalyst used in two systems and ...The photocatalytic performances of water oxidation were usually carried out in two different systems,photosensitizer and non-photosensitizer systems.There is few report about the same catalyst used in two systems and therefore it is of great significant to compare its role of the same catalyst in two systems and explore its different reaction mechanisms.In this work,first 4 kinds of metallic Co microparticles were obtained by different reduction methods through hydrothermal processes,and Co@Co_(3)O_(4) coreshell microparticles(1-4)were obtained from these metallic Co microparticles oxidized in air or in the reacting solution in situ.The core-shell structure of 1 was characterized by a series of analytical techniques.1-4 exhibited excellent activities and stabilities in the[Ru(bpy)3]^(2+)/S_(2) O_(8)^(2-)/light system when they were used as catalysts for the photocata lytic water oxidation.The maximum O2 evolution of 1 after 20 min’s illumination was 98.2 pmol,the O_(2) yield was 65.5%,the initial turnover frequency was 6.6×10^(-3),the initial quantum efficiency(ΦQYinitial)was 15.0%higher than Co(8.3%),CoO(11.7%),Co_(2)O_(3)(1.2%),Co_(3)O_(4)(2.8%)and 5(2.2%).Even after the sixth run,the catalytic activity of recovered 1 still remained 85.1%of initial activity.In addition,the photocatalytic performances of 1 in the[Ru(bpy)_(3)]^(2+)/S_(2)O_(8)2-/light system and S_(2) O_(8)^(2-)/light system were compared for the first time.In the nonphotosensitizer system,1 shows bifunctional roles and acts as optical absorption center and active catalytic site,and oxygen evolution rate is lower and it takes longer time.In the photosensitizer system,1 only acts as a catalyst,the photosensitizer enhances the light absorption and promotes water oxidation reaction with higher O_(2) yield and QE,meanwhile the photosensitizer brings the defect of high cost and instability into the system.Based on the results the two different reaction mechanisms were deeply discussed.展开更多
We hypothesized that neuroprotective agents targeting various pathways involved in cerebral ischemia/reperfusion(I/R)injury might be superior to that targeting single pathway.Here,we prepared a fusion protein(B-I)by c...We hypothesized that neuroprotective agents targeting various pathways involved in cerebral ischemia/reperfusion(I/R)injury might be superior to that targeting single pathway.Here,we prepared a fusion protein(B-I)by combining anti-apoptotic Bcl-x L(B)and anti-inflammatory IL-10(I).B-I could cross blood brain barrier by its N-terminal TAT domain,and be cleaved into separate B and I by Caspase-1.B-I treatment significantly reduced the cerebral infarct volume,better than B or I treatment alone,and equivalent to B and I treatment(B+I).Treatment with B or B-I significantly attenuated I/R-induced neuronal apoptosis as shown by the decrease in apoptotic rate and the inhibition of caspase-3 activity.Moreover,all recombinant proteins,especially B-I,remarkably attenuated I/R-induced up-regulation of TNF-α.These results suggested that fusion protein B-I inhibiting both inflammation and apoptosis provided better neuroprotective effects than inhibiting either one alone.Our study suggested that multiple pathways targeting brain I-R injury could enhance the neuroprotective effect,and it provided a new idea for the study of neuroprotective drugs for ischemic stroke.展开更多
The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a challenge.In this study,Ru_(2)P/AC effectively promoted reversible transformations bet...The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a challenge.In this study,Ru_(2)P/AC effectively promoted reversible transformations between unsaturated and saturated N‐heterocycles affording yields of 98%and 99%,respectively.Moreover,a remarkable enhancement in the reusability of Ru_(2)P/AC was observed compared with other Ru‐based catalysts.According to density functional theory calculations,the superior performance of Ru_(2)P/AC was ascribed to specific synergistic factors,namely geometric and electronic effects induced by P.P greatly reduced the large Ru‐Ru ensembles and finely modified the electronic structures,leading to a low reaction barrier and high desorption ability of the catalyst,further boosting the hydrogenation and acceptorless dehydrogenation processes.展开更多
Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction interme...Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.展开更多
The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions(ORR and OER) is critical to the practical application of zinc-air batteries(ZABs). Herein, a silica-assiste...The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions(ORR and OER) is critical to the practical application of zinc-air batteries(ZABs). Herein, a silica-assisted method is reported to integrate numerous accessible edge Fe-Nx sites into porous graphitic carbon(named Fe-N-G) for achieving highly active and robust oxygen electrocatalysis. Silica facilitates the formation of edge Fe-Nx sites and dense graphitic domains in carbon by inhibiting iron aggregation.The purification process creates a well-developed mass transfer channel for Fe-N-G. Consequently,Fe-N-G delivers a half-wave potential of 0.859 V in ORR and an overpotential of 344 m V at10 m A cm^(-2)in OER. During long-term operation, the graphitic layers protect edge Fe-Nx sites from demetallation in ORR and synergize with Fe OOH species endowing Fe-N-G with enhanced OER activity.Density functional theory calculations reveal that the edge Fe-Nx site is superior to the in-plane Fe-Nx site in terms of OH* dissociation in ORR and OOH* formation in OER. The constructed ZAB based on Fe-N-G cathode shows a higher peak power density of 133 m W cm^(-2)and more stable cycling performance than Pt/C + RuO2counterparts. This work provides a novel strategy to obtain high-efficiency bifunctional oxygen electrocatalysts through space mediation.展开更多
The functionalization of alkenes is a practical and important approach to access high value-added compounds.We herein realized the combination of energy transfer(EnT)and hydrogen atom transfer(HAT)process for the in s...The functionalization of alkenes is a practical and important approach to access high value-added compounds.We herein realized the combination of energy transfer(EnT)and hydrogen atom transfer(HAT)process for the in situ giving acyl azolium ions from the acyl electrophiles and N-heterocyclic carbenes(NHCs)catalysts under light irradiation,and developed three-component radical relay-type alkylacylation of readily available alkenes promoted by the cooperative NHC-photo cocatalysis to access structurally diversified alkylacylation products.The unique strategy for the NHC catalyst-bound acyl azoliums working as the intermolecular HAT reagent with the En T process was revealed.This protocol was also utilized to enable the late-stage functionalization of some important drugs and bioactive molecules.It featured readily bifunctionalization of alkenes,a wide range of alkenes and acyl imidazoles,mild reaction conditions,excellent selectivity,as well as broad functional group compatibility.Scale-up synthesis and a list of derivatization reactions displayed the potential synthetic application.Control experimental investigations and computational studies support that it involved the photoexcitation of in situ forming acyl azolium ions via En T process to access triplet diradical species with facile intersystem crossing,and acted as HAT reagents to undergo intermolecular HAT process,and then engaged in the following radical addition/radical-radical cross-coupling reaction with NHCs-linked radicals,resulting in alkylacylation products promoted by cooperative NHC and photocatalysis.展开更多
Several results on iterative methods for equilibrium problems have been proposed and studied in the literature.Most of these results are obtained when the associated bifunction of the equilibrium problem is either a m...Several results on iterative methods for equilibrium problems have been proposed and studied in the literature.Most of these results are obtained when the associated bifunction of the equilibrium problem is either a monotone or pseudomonotone operator.Results on iterative methods for equilibrium problems without monotonicity conditions on the bifunction are still few in the literature.In this paper,we study equilibrium problems for which the underlined bifunction is not assumed any form of monotonicity.We propose two weakly convergent iterative algorithms and one strongly convergent algorithm.We obtain our convergence results without assuming either monotonicity or pseudomonotonicity condition on the bifunction.Our proposed algorithms are tested numerically to be more efficient and faster than some few available algorithms for equilibrium problems without monotonicity in the literature.展开更多
An atomically dispersed FeCo-NC material with the 3D flower-like morphology was used as a unique substrate for the controllable deposition of ultrasmall NiFe layered double hydroxide nanodots(termed as NiFe-NDs)to sim...An atomically dispersed FeCo-NC material with the 3D flower-like morphology was used as a unique substrate for the controllable deposition of ultrasmall NiFe layered double hydroxide nanodots(termed as NiFe-NDs)to simultaneously promote the sluggish kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).The size-limiting growth of NiFe-NDs(~4.0 nm in diameter)was realized via the confinement of the 3D flower-like mesoporous structure and the rich N/O functionality of FeCo-NC.Benefiting from the distinctive structure with the simultaneously maximum exposure of both OER and ORR active sites,the NiFe-ND/FeCo-NC composite showed an ORR halfwave potential of 0.85 V and an OER potential of 1.66 V in0.1 mol L-1KOH at 10.0 mA cm-2.In-situ Raman analysis suggested the activity of OER was derived from the Ni sites on NiFe-ND/FeCo-NC.Moreover,the NiFe-ND/FeCo-NC-assembled Zn-air battery(ZAB)exhibited a very small discharge-charge voltage gap of 0.87 V at 20 mA cm-2and robust cycling stability.Furthermore,the NiFe-ND/FeCo-NC composite was also applicable for fabricating all-solid-state ZAB to power wearable electronics with superior cycling stability under deformation.Our work could enlighten a new applicable branch of atomically dispersed metal-nitrogen-carbon materials as unique substrates for fabricating multifunctional electrocatalysts.展开更多
Recent developments in nanochemistry offer precise morphology control of nanomaterials, which has significant impacts in the field of heterogeneous catalysis. Rational design of bifunctional catalysts can influence va...Recent developments in nanochemistry offer precise morphology control of nanomaterials, which has significant impacts in the field of heterogeneous catalysis. Rational design of bifunctional catalysts can influence various aspects of catalytic properties. In this review, a new class of bifunctional catalysts with a metal@silica yolk-shell nanostructure is introduced. This structure has many advantages as a heterogeneous catalyst since it ensures a homogeneous environment around each metal core, and particle sintering is effectively eliminated during high temperature reactions. The catalysts exhibit high activity and recyclability in gas- and solution-phase reactions. It is anticipated that appropriate selection of bifunctional components and optimal structural control will significantly further enhance the catalytic properties, and enable target reaction-oriented development of new catalysts.展开更多
Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino hifunctionaliz...Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino hifunctionalized mesoporous silica SBA-15 （PA-SBA-15） as U（VI） sorbent was fabricated through post-grafting method. The obtained mesoporous silica was character- ized by SEM, XRD, NMR and nitrogen sorption/desorption experiments, which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area. The adsorptivity of PA-SBA-15 for U（VI） from aqueous solution was investigated using batch sorption technique under different experimental conditions. The preliminary results show that the U（VI） sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h, and the U（VI） uptake is as large as 373 mg/g at pH 5.5 under 95℃. The sorption isotherm has been successfully modeled by the Langmuir isotherm, suggesting a monolayer homogeneous sorption of U（VI） in PA-SBA-15. The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution. The thermodynamics research shows that the sorption is a feasible and endothermic process. Based on these results, PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U（VI） ions from waste water and enrichment of U（VI） from a solution at a very low level.展开更多
In this work,six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were de-signed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives ...In this work,six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were de-signed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives via aldol reactions in water.Organocatalyzed by 5a,the direct aldol reactions of isatins with enolisable ketones under-went readily in water,furnishing the structurally diverse 3-alkyl-3-hydroxy-2-oxindoles in various stereoselectivi-ties(up to>99%dr and>99%ee).Moreover,a plausible transition state of the conducted aldol reactions was hy-pothesized to shed light on the observed stereoselectivities of the obtained 3-alkyl-3-hydroxy-2-oxindoles.展开更多
文摘The electrochemical hydrogenation(ECH)of 5-hydroxymethylfurfural(HMF)to 2,5-dihydroxymethylfuran(DHMF)represents a pivotal pathway for the electrocatalytic upgrading of biomass-based organic small molecules,offering significant reductions in energy consumption while producing value-added chemicals.The conversion of HMF to DHMF is challenging due to the high reduction potential and complex intermediates of HMF ECH under neutral environment.Also,the total efficiency is hindered by sluggish anodic oxygen evolution reaction(OER)kinetics.Herein,we report a synthesis of highly alloyed Pd-Pt bimetallene(Pd3Pt1 BML)for HMF ECH coupled with formic acid oxidation reaction(FAOR).Through a combination of in-situ Raman spectroscopy,electron paramagnetic resonance analysis,and theoretical calculations,we elucidate that the HMF adsorption on Pd atoms,strategically separated by Pt atoms,is weakened compared to pure Pd surfaces.Additionally,Pt atoms serve as crucial providers of active hydrogen to neighboring Pd atoms,synergistically enhancing the reaction kinetics of HMF conversion with a Faradaic efficiency>93%.Meanwhile,the atomically dispersed Pt atoms endow Pd_(3)Pt_(1) BML with high electrochemical performance for the direct pathway of FAOR at the anode.As a result,a FAOR-assisted HMF ECH system equipped with bifunctional Pd3Pt1 BML achieves the energy-efficient conversion of HMF to DHMF at electrolysis voltage of 0.72 V at 10 mA cm^(–2).This work provides insights into the rational design of bifunctional catalysts featuring two distinct types of active sites for advanced energy electrocatalysis and ECH.
基金the financial support provided by the National Natural Science Foundation of China(Nos.21572163 and 21873074)the Wenzhou Science&Technology Bureau(No.G20210032)。
文摘Nitrene transfer reactions are powerful tools in synthetic organic chemistry.In recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely pursued.Such species undergoes facile C-H amination,aziridination,and bifunctionalization of alkenes under the catalysis of different transition metals including Rh,Fe,Ru and others,enabling the efficient construction of various nitrogen-containing molecules.In this review,the recent developments in nitrene transfer reactions with carbamates via N-O bond cleavage were introduced based on different types of reaction,and the key mechanistic information and synthetic applications of the methodologies were discussed.
基金financially supported by the National Natural Science Foundation of China(21802048,21805103,21805104)the Fundamental Research Funds for the Central Universities(2018KFYXKJC044,2018KFYYXJJ121,2017KFXKJC002,2017KFYXJJ164)the National 1000 Young Talents Program of China。
文摘Developing robust oxygen electrocatalyst with high-performance is very significant for practical rechargeable Zn-air battery.We report herein the preparation of three-dimensional continuous nanocarbon network composed of interconnected nitrogen-doped carbon nanotubes and its application as oxygen electrocatalysis in rechargeable Zn-air battery.Except the excellent electrochemical bifunctionality,this carbon nanotube matrix also delivers an impressive battery performance.Specifically,an opencircuit voltage of 1.50 V as well as a high power density of 220 m W cm^(-2) with remarkable cycling stability for 1600 h is achieved in the rechargeable Zn-air battery.The study not only provides an efficient bifunctional oxygen electrocatalyst but more importantly may pave significant concepts in designing robust electrode for long-life rechargeable Zn-air battery and other energy technologies.
基金financially supported by the National Natural Science Foundation of China(51572166)the project funded by China Postdoctoral Science Foundation(2021 M702073)support from the Program for Professors with Special Appointments(Eastern Scholar:TP2014041)at Shanghai Institutions of Higher Learning。
文摘Electrocatalysts are one of the essential components for the devices of high-efficiency green energy storage and conversion,such as metal-air cells,fuel cells,and water electrolysis systems.While catalysts made from noble metals possess high catalytic performance in both oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),their scarcity and expensiveness significantly limit large-scale applications.In this regard,metal-free/non-noble metal carbon-based catalysts have become competitive alternatives to replace catalysts made of noble metals.Nevertheless,low catalytic ORR/OER performance is the challenge of carbon-based catalysts for the commercial applications of metal-air batteries.To solve the problem of poor catalytic performance,two strategies have been proposed:(1)controlling the microstructure of the catalysts to expose more active sites as the channels of rapid mass and electron transfer;and(2)reducing the reaction energy barrier by optimizing the electronic structures of the catalysts via surface engineering.Here,we review different types of bifunctional ORR/OER electrocatalysts with the activated surface sites.We focus on how the challenge can be overcome with different methods of material synthesis,structural and surface characterization,performance validation/optimization,to outline the principles of surface modifications behind catalyst designs.In particular,we provide critical analysis in the challenges that we are facing in structural design and surface engineering of bifunctional ORR/OER catalysts and indicate the possible solution for these problems,providing the society with clearer ideas on the practical prospects of noble-metal-free electrocatalysts for their future applications.
基金supported by the National Natural Science Foundation of China (No.20773120)National 973 Project of China (No.2005CB221403)
文摘A new propene production route from 1-butene metathesis has been developed on heterogeneous 10WO3/Al2O3-HY catalysts with different HY contents. It is found that the catalysts play bi-functionally first for the isomerization of 1-butene to 2-butene and then for the cross-metathesis between 1-butene and 2-butene to propene and 2-pentene. The combination of HY zeolite and Al2O3 is prerequisite for the production of propene. The propene yield keeps increasing with the HY content in the range of 10-70 wt%, where 10WO3/Al2O3-70HY exhibits the highest propene yield. The MS-H2-TPR and MS-O2-TPO characterizations indicate that the increase of HY content in the catalysts weakens the interaction between W species and supports, whereas enhance the probability of coking on the metal species and acid sites.
文摘Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the difference with the conventional FT/zeolite catalyst have not been investigated.Herein,three one-dimensional SAPO zeolites with diverse micropore sizes were synthesized and assembled with ZnAlO_(x)with spinel structure.It was found that ZnAlO_(x)/SAPO-41 and ZnAlO_(x)/SAPO-11 with medium micropore sizes favored the formation of C_(5)–C_(11)hydrocarbons with a high content of iso-paraffins.The characterizations pointed out that the formation of iso-paraffins over SAPO-11 followed a pore-mouth catalysis mechanism,which means the isomerization of linear hydrocarbons can only take place near the pore mouth region of zeolites.This mechanism only allows the formation of mono-branched iso-paraffins in the C_(5)–C_(11)range,which are less prone to be cracked than their di-branched isomers.A careful comparative analysis between ZnAlO_(x)/SAPO-11 and Co/H-meso-ZSM-5 was also made in terms of product distribution,activity,and stability.
基金supported by the Beijing Natural Science Foundation (2222004)。
文摘The recharged zinc-air battery(ZAB) has drawn significant attention owing to increasing requirement for energy conversion and storage devices.Fabricating the efficient bifunctional oxygen catalyst using a convenient strategy is vitally important for the rechargeable ZAB.In this study,the bimetallic ZIFs-containing electrospun(ES) carbon nanofibers membrane with hierarchically porous structure was prepared by coaxial electrospinning and carbonization process,which was expected to be a bifunctional electrocatalyst for ZABs.Owing to the formed dual single-atomic sites of Co-N_(4) and Zn-N_(4),the obtained ES-Co/ZnCNZIFexhibited the preferable performance toward oxygen reduction reaction(ORR) with E1/2of 0.857 V and JLof 5.52 mA cm^(-2),which were more than Pt/C.Meanwhile,it exhibited a marked oxygen evolution reaction(OER) property with overpotential of 462 mV due to the agglomerated metallic Co nanoparticles.Furthermore,the ZAB based on the ES-Co/Zn-CNZIFcarbon nanofibers membranes delivered peak power density of 215 mW cm^(-2),specific capacity of 802.6 mA h g^(-1),and exceptional cycling stability,far larger than Pt/C+RuO_(2)-based ZABs.A solid-state ZAB based on ES-Co/Zn-CNZIFshowed better flexibility and stability with different bending angles.
文摘The optimum Mo/[H^+] ratio per unit cell of the active precursors in Mo/HZSM-5 catalysts for methane dehydro-aromatization, measured by1H MAS NMR, was found to be about 1 when adjusting the acid sites by altering either the SiO2/Al2O3 ratios or the Mo loading. This implies that a concerted interaction between the Mo species and the Bronsted acid sites probably features the bifunctionality of the Mo/HZSM-5 catalyst. On the other hand, it was found that the driving force for Mo species to move into the HSZM-5 zeolite channels and the interaction between the Mo species and the Bronsted acid sites are closely and proportionably related with the amount of Bronsted acid sites per unit cell.
基金the funding support from the National Natural Science Foundation of China(No.21861035)the University Scientific Research Project of Xinjiang Uyghur Autonomous Region(No.XJEDU2017I001)。
文摘The photocatalytic performances of water oxidation were usually carried out in two different systems,photosensitizer and non-photosensitizer systems.There is few report about the same catalyst used in two systems and therefore it is of great significant to compare its role of the same catalyst in two systems and explore its different reaction mechanisms.In this work,first 4 kinds of metallic Co microparticles were obtained by different reduction methods through hydrothermal processes,and Co@Co_(3)O_(4) coreshell microparticles(1-4)were obtained from these metallic Co microparticles oxidized in air or in the reacting solution in situ.The core-shell structure of 1 was characterized by a series of analytical techniques.1-4 exhibited excellent activities and stabilities in the[Ru(bpy)3]^(2+)/S_(2) O_(8)^(2-)/light system when they were used as catalysts for the photocata lytic water oxidation.The maximum O2 evolution of 1 after 20 min’s illumination was 98.2 pmol,the O_(2) yield was 65.5%,the initial turnover frequency was 6.6×10^(-3),the initial quantum efficiency(ΦQYinitial)was 15.0%higher than Co(8.3%),CoO(11.7%),Co_(2)O_(3)(1.2%),Co_(3)O_(4)(2.8%)and 5(2.2%).Even after the sixth run,the catalytic activity of recovered 1 still remained 85.1%of initial activity.In addition,the photocatalytic performances of 1 in the[Ru(bpy)_(3)]^(2+)/S_(2)O_(8)2-/light system and S_(2) O_(8)^(2-)/light system were compared for the first time.In the nonphotosensitizer system,1 shows bifunctional roles and acts as optical absorption center and active catalytic site,and oxygen evolution rate is lower and it takes longer time.In the photosensitizer system,1 only acts as a catalyst,the photosensitizer enhances the light absorption and promotes water oxidation reaction with higher O_(2) yield and QE,meanwhile the photosensitizer brings the defect of high cost and instability into the system.Based on the results the two different reaction mechanisms were deeply discussed.
基金National Natural Science Foundation of China(Grant No.81573333,81503060)
文摘We hypothesized that neuroprotective agents targeting various pathways involved in cerebral ischemia/reperfusion(I/R)injury might be superior to that targeting single pathway.Here,we prepared a fusion protein(B-I)by combining anti-apoptotic Bcl-x L(B)and anti-inflammatory IL-10(I).B-I could cross blood brain barrier by its N-terminal TAT domain,and be cleaved into separate B and I by Caspase-1.B-I treatment significantly reduced the cerebral infarct volume,better than B or I treatment alone,and equivalent to B and I treatment(B+I).Treatment with B or B-I significantly attenuated I/R-induced neuronal apoptosis as shown by the decrease in apoptotic rate and the inhibition of caspase-3 activity.Moreover,all recombinant proteins,especially B-I,remarkably attenuated I/R-induced up-regulation of TNF-α.These results suggested that fusion protein B-I inhibiting both inflammation and apoptosis provided better neuroprotective effects than inhibiting either one alone.Our study suggested that multiple pathways targeting brain I-R injury could enhance the neuroprotective effect,and it provided a new idea for the study of neuroprotective drugs for ischemic stroke.
文摘The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a challenge.In this study,Ru_(2)P/AC effectively promoted reversible transformations between unsaturated and saturated N‐heterocycles affording yields of 98%and 99%,respectively.Moreover,a remarkable enhancement in the reusability of Ru_(2)P/AC was observed compared with other Ru‐based catalysts.According to density functional theory calculations,the superior performance of Ru_(2)P/AC was ascribed to specific synergistic factors,namely geometric and electronic effects induced by P.P greatly reduced the large Ru‐Ru ensembles and finely modified the electronic structures,leading to a low reaction barrier and high desorption ability of the catalyst,further boosting the hydrogenation and acceptorless dehydrogenation processes.
基金supported by C1 Gas Refinery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science,ICT & Future Planning (2015M3D3A1A01064908)
文摘Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.
基金financial support from the National Key Research and Development Project (2017YFB0308200)the CAS Key Laboratory of Carbon Materials (KLCMKFJJ2011)。
文摘The development of advanced bifunctional oxygen electrocatalysts for oxygen reduction and evolution reactions(ORR and OER) is critical to the practical application of zinc-air batteries(ZABs). Herein, a silica-assisted method is reported to integrate numerous accessible edge Fe-Nx sites into porous graphitic carbon(named Fe-N-G) for achieving highly active and robust oxygen electrocatalysis. Silica facilitates the formation of edge Fe-Nx sites and dense graphitic domains in carbon by inhibiting iron aggregation.The purification process creates a well-developed mass transfer channel for Fe-N-G. Consequently,Fe-N-G delivers a half-wave potential of 0.859 V in ORR and an overpotential of 344 m V at10 m A cm^(-2)in OER. During long-term operation, the graphitic layers protect edge Fe-Nx sites from demetallation in ORR and synergize with Fe OOH species endowing Fe-N-G with enhanced OER activity.Density functional theory calculations reveal that the edge Fe-Nx site is superior to the in-plane Fe-Nx site in terms of OH* dissociation in ORR and OOH* formation in OER. The constructed ZAB based on Fe-N-G cathode shows a higher peak power density of 133 m W cm^(-2)and more stable cycling performance than Pt/C + RuO2counterparts. This work provides a novel strategy to obtain high-efficiency bifunctional oxygen electrocatalysts through space mediation.
基金supported by the Fundamental Research Funds for the Central Universities(2042025kf0032)the National Natural Science Foundation of China(22271226,22171134,22071186,22071187)+1 种基金the National Key R&D Program of China(2023YFA1506700)the National Youth Talent Support Program。
文摘The functionalization of alkenes is a practical and important approach to access high value-added compounds.We herein realized the combination of energy transfer(EnT)and hydrogen atom transfer(HAT)process for the in situ giving acyl azolium ions from the acyl electrophiles and N-heterocyclic carbenes(NHCs)catalysts under light irradiation,and developed three-component radical relay-type alkylacylation of readily available alkenes promoted by the cooperative NHC-photo cocatalysis to access structurally diversified alkylacylation products.The unique strategy for the NHC catalyst-bound acyl azoliums working as the intermolecular HAT reagent with the En T process was revealed.This protocol was also utilized to enable the late-stage functionalization of some important drugs and bioactive molecules.It featured readily bifunctionalization of alkenes,a wide range of alkenes and acyl imidazoles,mild reaction conditions,excellent selectivity,as well as broad functional group compatibility.Scale-up synthesis and a list of derivatization reactions displayed the potential synthetic application.Control experimental investigations and computational studies support that it involved the photoexcitation of in situ forming acyl azolium ions via En T process to access triplet diradical species with facile intersystem crossing,and acted as HAT reagents to undergo intermolecular HAT process,and then engaged in the following radical addition/radical-radical cross-coupling reaction with NHCs-linked radicals,resulting in alkylacylation products promoted by cooperative NHC and photocatalysis.
文摘Several results on iterative methods for equilibrium problems have been proposed and studied in the literature.Most of these results are obtained when the associated bifunction of the equilibrium problem is either a monotone or pseudomonotone operator.Results on iterative methods for equilibrium problems without monotonicity conditions on the bifunction are still few in the literature.In this paper,we study equilibrium problems for which the underlined bifunction is not assumed any form of monotonicity.We propose two weakly convergent iterative algorithms and one strongly convergent algorithm.We obtain our convergence results without assuming either monotonicity or pseudomonotonicity condition on the bifunction.Our proposed algorithms are tested numerically to be more efficient and faster than some few available algorithms for equilibrium problems without monotonicity in the literature.
基金financially supported by the National Natural Science Foundation of China(21701101)the National Key Research and Development Project,Key Projects of Intergovernmental International Innovation Cooperation(2018YFE0118200 and 2016YFF0204402)+4 种基金the Fundamental Research Funds for the Central Universities(18CX06063A)the Key Research and Development Project of Shandong Province(2019JZZY010506)the Scientific Research Awards Foundation for Outstanding Young Scientists of Shandong Province(ZR2018JL010)the Joint Fund of Outstanding Young Talents of Shandong Province(ZR2017BB018)the Program of Qingdao Scientific and Technological Innovation High-level Talents Project(172-1-1-zhc)。
文摘An atomically dispersed FeCo-NC material with the 3D flower-like morphology was used as a unique substrate for the controllable deposition of ultrasmall NiFe layered double hydroxide nanodots(termed as NiFe-NDs)to simultaneously promote the sluggish kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).The size-limiting growth of NiFe-NDs(~4.0 nm in diameter)was realized via the confinement of the 3D flower-like mesoporous structure and the rich N/O functionality of FeCo-NC.Benefiting from the distinctive structure with the simultaneously maximum exposure of both OER and ORR active sites,the NiFe-ND/FeCo-NC composite showed an ORR halfwave potential of 0.85 V and an OER potential of 1.66 V in0.1 mol L-1KOH at 10.0 mA cm-2.In-situ Raman analysis suggested the activity of OER was derived from the Ni sites on NiFe-ND/FeCo-NC.Moreover,the NiFe-ND/FeCo-NC-assembled Zn-air battery(ZAB)exhibited a very small discharge-charge voltage gap of 0.87 V at 20 mA cm-2and robust cycling stability.Furthermore,the NiFe-ND/FeCo-NC composite was also applicable for fabricating all-solid-state ZAB to power wearable electronics with superior cycling stability under deformation.Our work could enlighten a new applicable branch of atomically dispersed metal-nitrogen-carbon materials as unique substrates for fabricating multifunctional electrocatalysts.
文摘Recent developments in nanochemistry offer precise morphology control of nanomaterials, which has significant impacts in the field of heterogeneous catalysis. Rational design of bifunctional catalysts can influence various aspects of catalytic properties. In this review, a new class of bifunctional catalysts with a metal@silica yolk-shell nanostructure is introduced. This structure has many advantages as a heterogeneous catalyst since it ensures a homogeneous environment around each metal core, and particle sintering is effectively eliminated during high temperature reactions. The catalysts exhibit high activity and recyclability in gas- and solution-phase reactions. It is anticipated that appropriate selection of bifunctional components and optimal structural control will significantly further enhance the catalytic properties, and enable target reaction-oriented development of new catalysts.
基金supported by the National Natural Science Foundation of China (91026007)the "Strategic Priority Research program" of the Chinese Academy of Sciences (XDA03010401,XDA03010403)
文摘Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino hifunctionalized mesoporous silica SBA-15 （PA-SBA-15） as U（VI） sorbent was fabricated through post-grafting method. The obtained mesoporous silica was character- ized by SEM, XRD, NMR and nitrogen sorption/desorption experiments, which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area. The adsorptivity of PA-SBA-15 for U（VI） from aqueous solution was investigated using batch sorption technique under different experimental conditions. The preliminary results show that the U（VI） sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h, and the U（VI） uptake is as large as 373 mg/g at pH 5.5 under 95℃. The sorption isotherm has been successfully modeled by the Langmuir isotherm, suggesting a monolayer homogeneous sorption of U（VI） in PA-SBA-15. The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution. The thermodynamics research shows that the sorption is a feasible and endothermic process. Based on these results, PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U（VI） ions from waste water and enrichment of U（VI） from a solution at a very low level.
基金We thank the Beijing Municipal Commission of Education(No.JC015001200902)the Beijing Municipal Natural Science Foundation(Nos.710201,2122008)+1 种基金the Basic Research Foundation of Beijing University of Technology(No.X4015001201101)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality(No.PHR201008025)and the Doctoral Scientific Research Start-up Foundation of Beijing University of Technology(No.52015001200701)for financial supports.
文摘In this work,six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were de-signed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives via aldol reactions in water.Organocatalyzed by 5a,the direct aldol reactions of isatins with enolisable ketones under-went readily in water,furnishing the structurally diverse 3-alkyl-3-hydroxy-2-oxindoles in various stereoselectivi-ties(up to>99%dr and>99%ee).Moreover,a plausible transition state of the conducted aldol reactions was hy-pothesized to shed light on the observed stereoselectivities of the obtained 3-alkyl-3-hydroxy-2-oxindoles.
