Ring-opening copolymerization of CO_(2) and epoxides is a promising way to manufacture high value-added materials.Despite a variety of catalyst systems have been reported,the reaction is still limited by low activity ...Ring-opening copolymerization of CO_(2) and epoxides is a promising way to manufacture high value-added materials.Despite a variety of catalyst systems have been reported,the reaction is still limited by low activity and polymer selectivity.Herein,a strategy of polymerization-enhanced Lewis acidity is reported to construct a series of highly efficient polymeric aluminum porphyrin catalysts(PAPCs).The characterization of the coordination equilibrium constant(K_(eq))showed significantly enhanced Lewis acidity of PAPC(K_(eg)=18.2 L/mol)compared to the monomeric counterpart(K_(eq)=6.4 L/mol),accompanied with increased turnover frequency(TOF)from 136 h^(-1) to 5500 h^(-1).Through detailed regulation of Lewis acidity,the highly Lewis acidic PAPC-OTs displayed a record high TOF of 30,200 h^(-1) with polymer selectivity of up to 99%.展开更多
The Jellium closed-shell model,a cornerstone of cluster science,has long guided the design of superatoms by dictating electron-counting rules.However,its reliance on precise control of cluster composition and electron...The Jellium closed-shell model,a cornerstone of cluster science,has long guided the design of superatoms by dictating electron-counting rules.However,its reliance on precise control of cluster composition and electron shell occupancy presents significant experimental challenges.Here,we introduce a ligation strategy that circumvents these limitations by demonstrating that the adiabatic electron affinity(AEA) of aluminum-based clusters,whether with filled or partially filled electron shells,can be dramatically enhanced through the attachment of organic Lewis acid ligands.It was evidenced that the AEA of PAl12can be significantly increased by 2.17 e V after the ligation of two ligands,indicating a remarkable improvement in its electron-accepting ability.This approach yields superhalogen species,offering a versatile and practical means to tune the electronic properties of clusters while preserving their superatomic states,independent of shell occupancy.Remarkably,this ligand-induced modulation is not confined to naked clusters but also extends to nano-confined systems,hinting at its broader applicability.Given the indispensable role of ligands in cluster synthesis,this strategy holds promise for advancing the field of condensed-phase superatom synthesis,potentially complementing traditional electron-counting rules in a broader range of applications.展开更多
It is urgent to develop a new deep desulfurization process of fuels as the environmental pollution increases seriously. In this work, a series of Lewis acidic ionic liquids （ILs） [C43MPy]Cl/nZnCl2 （n=1, 1.5, 2, 3）...It is urgent to develop a new deep desulfurization process of fuels as the environmental pollution increases seriously. In this work, a series of Lewis acidic ionic liquids （ILs） [C43MPy]Cl/nZnCl2 （n=1, 1.5, 2, 3） were synthesized and used in extraction and catalytic oxidative desulfurization （ECOD） of the fuels. The effects of the Lewis acidity of ILs, the molar ratio of H2O2/sulfur, temperatures, and different substrates including dibenzothiophene （DBT）, benzothiophene （BT） and thiophene （TS）, on sulfur removal were investigated. The results indicated that [C43MPy]Cl/3ZnCl2 presented near 100% DBT removal of model oil under conditions of 323 K, H2O2/DBT molar ratio 6：1. Kinetics for the removal of DBT, BT and TS by the [C43MPy]Cl/3ZnCl2-H2O2 system at 323 K is first-order with the apparent rate constants of 1.1348, 0.2226 and 0.0609 h-1, and the calculated apparent activation energies for DBT, BT and TS were 61.13, 60.66, and 68.14 kJ/mol from 298 to 308 K, re- spectively. After six cycles of the regenerated [C43MPy]Cl/3ZnCl2, the sulfur removal had a slight decrease. [C43MPy]Cl/ 3ZnCl2 showed a good desulfurization performance under optimal conditions.展开更多
The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material structure.In this study,we prepared a novel Sn S_(2)...The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material structure.In this study,we prepared a novel Sn S_(2)/black phosphorus(BP)two-dimensional(2D)-2D heterostructure via the in situ hydrothermal growth of Sn S_(2)nanosheets on exfoliated BP lamellae for NO_(2)sensing applications.In the Sn S_(2)/BP composite,the holes with high oxidizability in p-type BP could oxidize Sn^(2+)into Sn^(4+),thus inhibiting the formation of Lewis acidic S vacancies.This Sn^(2+)/Lewis acidity suppression of the composite was further confirmed by X-ray photoelectron spectroscopy and acidic double-layer capacitance analyses,and promoted the adsorption and detection of acidic NO_(2).Owing to its valence and Lewis acidity engineering,the Sn S_(2)/BP heterostructure sensor could detect trace levels of NO_(2)as low as 100 ppb(parts per billion)with high response,fast response/recovery,good stability,and selectivity at room temperature.The high absorption energy of NO_(2)(à0.74 e V),as indicated by the density functional theory calculations,suggests that NO_(2)was chemically adsorbed on the Sn S_(2)/BP surface,which was also evidenced by the in situ Raman spectroscopy results.This work opens up interesting opportunities for the rational design of highly efficient NO_(2)gas sensors through Lewis acidity modification and interface engineering.展开更多
The Lewis acidity scale of boron trihalides BX3 (X=F, Cl, Br, I) and character of the boron-halogen bonds have been studied by means of DV-Xa approach. Present results show that the acid strength of boron trihalides i...The Lewis acidity scale of boron trihalides BX3 (X=F, Cl, Br, I) and character of the boron-halogen bonds have been studied by means of DV-Xa approach. Present results show that the acid strength of boron trihalides increases in the order BF3<BCl3<BBr3<BI3, in excellent agreement with experiments. Based on boron-halogen bonding character, the valence of boron atom in boron compounds can be considered as equal to five instead of three which seems to be more reasonable.展开更多
Direct electrolysis of seawater offers a transformative technology for sustainable hydrogen production,circumventing the constraint of freshwater scarcity.However,the serious electrode corrosion and competitive chlori...Direct electrolysis of seawater offers a transformative technology for sustainable hydrogen production,circumventing the constraint of freshwater scarcity.However,the serious electrode corrosion and competitive chloride oxidation reactions make oxygen evolution reaction(OER)in seawater extremely challenging.Herein,the low-cost and scalable CoFe layered double hydroxides with Cl^(-)intercalation and decorated with Ce(OH)_(3)(named as CoFe-Cl^(-)/Ce(OH)_(3))catalyst is synthesized via rapid electrodeposition under ambient conditions,which is quickly reconstructed into a CeO_(2)decorated and Cl^(-)intercalated CoFeOOH(CoFeOOH-Cl^(-)/CeO_(2))during OER.Theoretical investigation reveals that Cl^(-)intercalation weakens the adsorption ability of Cl^(-)on Co/Fe atoms and hinders unfavorable coupling with chloride,thereby preventing the chlorine corrosion process and enhancing catalytic stability and activity.The CeO_(2)with hard Lewis acidity preferentially binds to OH-with harder Lewis base to ensure the OH-rich microenvironment around catalyst even under high current operating conditions,thus further enhancing stability and improving OER activity.The functionalized CoFe-Cl^(-)/Ce(OH)_(3)delivers 1000 mA cm^(-2)current density at only 329 mV overpotential with excellent stability for 1000 h under alkaline seawater.Electrochemical experiments elucidate the OER catalytic mechanism in which CeO_(2)serves as a co-catalyst for enriching OH-and CoFeOOH-Cl^(-)is the active species.Our work is a substantial step towards achieving massive and sustainable production of hydrogen fuel from immense seawater.展开更多
The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electroni...The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electronic structure. Here, a nickel-based transition metal carbide catalyst(Ni/TMC) with high Lewis acidity was prepared by self-assembly of transition metal carbide(TMC) and nickel, which exhibited excellent performance on synergistic hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural(HMF) into liquid biofuel 2,5-dimethylfuran(DMF).Notably, Ni/WC with the highest Lewis acidity(4728.3 μmol g^(-1)) can achieve 100% conversion of HMF to 97.6% yield of DMF, with a turnover frequency of up to 46.5 h^(-1). The characterization results demonstrate that the rich Lewis acid sites yielded by the synergistic effect between Ni species and TMC are beneficial for the C=O hydrogenation and C–O cleavage, thereby accelerating the process of hydrodeoxygenation(HDO). Besides, a kinetic model for the HDO of HMF to DMF process has been established based on the experimental results, which elucidated a significant correlation between the measured and the predicted data(R^(2)> 0.97). Corresponding to the adsorption configuration of Ni/WC and substrate determined by in-situ FTIR characterization, this study provides a novel insight into the selective conversion of HMF process for functional biofuel and bio-chemicals.展开更多
High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kin...High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kinetics.To solve the above problems,it is proposed to enhance the hydrogen storage properties of LiBH_(4)through the synergistic effect of Brønsted and Lewis acid in Hβzeolite.Composite hydrogen storage systems with different mass ratios were prepared by simple ball-milling.At a LiBH_(4)-to-Hβmass ratio of 6:4,the 6LiBH_(4)-4Hβsystem released hydrogen at 190℃and achieved a hydrogen release capacity of 7.0 wt%H_(2)upon heating to 400℃.More importantly,the hydrogen release capacity of the system reached 6.02 wt%at 350℃under isothermal conditions after 100 min and 7.2 wt%at 400℃under isothermal conditions after 80 min,whereas the pristine LiBH_(4)only achieved 2.2 wt%.The improvement in hydrogen storage performance of the system was mainly attributed to two factors:(i)Lewis acid sites with acceptable electrons in the Hβweaken the electron density of B-H bonds in LiBH_(4),and(ii)the H+proton from the Brønsted acid sites and H−of LiBH_(4)undergo a H^(+)+H^(−)=H_(2)reaction.Theoretical calculations revealed that the Lewis and Brønsted acid sites in the Hβzeolite are conducive to the weakening of B-H bonds and that storage charge transfer occurs near the Lewis acid sites.The present work provides new insights into improving the hydrogen storage performance of LiBH_(4)by weakening the B-H bonds in the LiBH_(4).展开更多
Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. ...Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. The ionic liquids were used as catalyst for Friedel-Crafts alkylation of benzene and 1-dodecene. The turnovers of l-dodecene were higher than 99%. Monoalkylbenzene selectivity was 98%, while the 2-substituent product selectivity was 45%.展开更多
Avery wide range of the C3^=/C2^= ratio from 0.72 to 7.56 with high C2^= ＋ C3^= selectivity of around 66%in the methanol-to-hydrocarbons process can be realized over ZSM-5 catalyst in a fixed-bed reactor.We firstly c...Avery wide range of the C3^=/C2^= ratio from 0.72 to 7.56 with high C2^= ＋ C3^= selectivity of around 66%in the methanol-to-hydrocarbons process can be realized over ZSM-5 catalyst in a fixed-bed reactor.We firstly conduct a single factor experiment of acidity,demonstrating that the acidity control of MTH catalyst is crucial to adjusting light olefins selectivity.Weak Bronsted acid sites favor to high C3^= selectivity（59.0%）due to the suppression of the conversion reactions from the alkene-based to arene-based cycle,while Lewis acid sites conduce to high C2^= selectivity（39.6%） due to the promotion of the conversion reactions for the aromatics formation and steric constraints of Lewis acid sites making the aromatics crack more efficiently to C2^=.展开更多
Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electro...Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.展开更多
Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional materials.Benefiting from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,r...Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional materials.Benefiting from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,rich surface chemistry,superior mechanical strength,MXenes exhibit great application prospects in energy storage and conversion,sensors,optoelectronics,electromagnetic interference shielding and biomedicine.Nevertheless,two issues seriously deteriorate the further development of MXenes.One is the high experimental risk of common preparation methods such as HF etching,and the other is the difficulty in obtaining MXenes with controllable surface groups.Recently,Lewis acidic etching,as a brand-new preparation strategy for MXenes,has attracted intensive attention due to its high safety and the ability to endow MXenes with uniform terminations.However,a comprehensive review of Lewis acidic etching method has not been reported yet.Herein,we first introduce the Lewis acidic etching from the following four aspects:etching mechanism,terminations regulation,in-situ formed metals and delamination of multi-layered MXenes.Further,the applications of MXenes and MXene-based hybrids obtained by Lewis acidic etching route in energy storage and conversion,sensors and microwave absorption are carefully summarized.Finally,some challenges and opportunities of Lewis acidic etching strategy are also presented.展开更多
Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxi...Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of carbon.Herein, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).展开更多
An experimental investigation was conducted to understand the roles of the Br？nsted acid H2SO4 and Lewis acid Al2（SO4）3 in methyl levulinate（ML） production from biomass carbohydrates, including glucose,fructose a...An experimental investigation was conducted to understand the roles of the Br？nsted acid H2SO4 and Lewis acid Al2（SO4）3 in methyl levulinate（ML） production from biomass carbohydrates, including glucose,fructose and cellulose. The product distributions with different catalysts revealed that the Lewis acid was responsible for the isomerization of methyl glucoside（MG）, producing a significant amount of the subsequent product 5-methoxymethylfurfural（MMF）, while the Br？nsted acid facilitated the production of ML from MMF. Al2（SO4）3 was efficient for monosaccharide conversion but not for cellulose. Using ball-milled cellulose with Al2（SO4）3 resulted in a desired ML yield within a reasonable reaction time. The significant catalysis performances of two types of acids will guide the design of efficient catalytic processes for the selective conversion of biomass into levulinate esters.展开更多
The self-aldol condensation of aldehydes was investigated with rare-earth cations stabilized by[Si]Beta zeolites in parallel with bulk rare-earth metal oxides.Good catalytic performance was achieved with all Lewis aci...The self-aldol condensation of aldehydes was investigated with rare-earth cations stabilized by[Si]Beta zeolites in parallel with bulk rare-earth metal oxides.Good catalytic performance was achieved with all Lewis acidic rare-earth cations stabilized by zeolites and yttrium appeared to be the best metal choice.According to the results of several complementary techniques,i.e.,temperature-programmed surface reactions,in situ diffuse reflectance infrared Fourier transform spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,the reaction pathway and mechanism of the aldehyde self-aldol condensation over Y/Beta catalyst were studied in more detail.Density functional theory calculations revealed that aldol dehydration was the rate-limiting step.The hydroxyl group at the open yttrium site played an important role in stabilizing the transition state of the aldol dimer reducing the energy barrier for its hydration.Lewis acidic Y(OSi)(OH)2 stabilized by zeolites in open configurations were identified as the preferred active sites for the self-aldol condensation of aldehydes.展开更多
CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ce...CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ceria catalysts for NRR remains a challenge due to the poor knowledge of the catalytic mechanism, particularly the nature of the active sites and how they catalyze NRR. Here, using first-principle calculations, we investigated the NRR catalysis process involving adjacent Ce Lewis acid clusters formed on(111),(110), and(100) facets of CeO_(2) as active sites. Our results revealed that the assembled structures of the Ce Lewis acid as active centers after the oxygen vacancies(Ovs) were opened. The exposed Ce sites on CeO_(2)(111), CeO_(2)(110), and CeO_(2)(100) can cause N_(2) to be adsorbed in a ‘‘lying-down" manner, which facilitates the N2 activation and thus leads to much higher NRR activity. Furthermore, from the perspective of electronic structure, we establish two useful descriptors for assessing the NRR activity on ceria with Ovs:The N–N bond strength of the adsorbed N_(2) and the adsorption energy of the *N_(2)H intermediate. This work thus provides direct guidance for the design of more-effective oxide catalysts without the use of scarce metals.展开更多
The azides were reduced to the corresponding amines by two new metal/Lewis acid systems in water or in aqueous EtOH in yields ranging from 80%-95%. The reaction rates were faster in water than in aqueous EtOH in most...The azides were reduced to the corresponding amines by two new metal/Lewis acid systems in water or in aqueous EtOH in yields ranging from 80%-95%. The reaction rates were faster in water than in aqueous EtOH in most cases. All 16 azides with different functional groups were well reduced to the corresponding amines in excellent yields and reaction rates.展开更多
The incorporation of boron into carbon material can significantly enhance its capacity performances.However,the origin of the promotion effect of boron doping on electrochemical performances is still unclear,in part d...The incorporation of boron into carbon material can significantly enhance its capacity performances.However,the origin of the promotion effect of boron doping on electrochemical performances is still unclear,in part due to the inadequate exposure of boron configurations resulting from the complexity of traditional carbon materials.To overcome this issue,herein,a series of boron-doped graphene with highly-exposed boron configurations are prepared by tuning annealing temperature.Then the correlation between boron configurations and the electrochemical performances is investigated.The combination of density-functional theory(DFT)computation and NH3-TPD/Py-FTIR indicates that the BCO_(2)configuration formed on the surface of graphene is easier to accept lone-pair electrons than BC_(2)O and BC_(3)configurations due to the stronger Lewis acidity.Such an electronic structure can effectively reduce the number of unstable electron donors and stabilize the electrochemical interface,which is proved by NMR,and critical for improving the electrochemical performances.Further experiments confirm that the optimized BG800 with the largest amount of BCO_(2)configuration presents ultralow leak current,improved cyclic stability,and better rate performance in SBPBF4/PC.This work would provide an insight into the design of high-performance boron-doped carbon materials towards energy storage.展开更多
Lewis acidic ionic liquids were used to catalyze the reaction of epoxypropane with POCl3. Considering the lower cost and catalytic activities, we concluded that [Et3NH]Cl/AlCl3 was the most attractive ionic liquid fro...Lewis acidic ionic liquids were used to catalyze the reaction of epoxypropane with POCl3. Considering the lower cost and catalytic activities, we concluded that [Et3NH]Cl/AlCl3 was the most attractive ionic liquid from an economical point of view. But it would be easily inactivated because of sensitive to water and air. Moreover, it could not be reused easily because of difficulty recovery in the reaction. However, supporting [Et3NH]Cl/AlCl3 catalyst could resolve above problems. Supporting [Et3NH]Cl/ AlCl3 catalyst could be separated by filter easily and reused 5 times in 98% yield. Furthermore, the catalyst was applicable to other epoxy ether cleaving reactions.展开更多
A substitution reaction of amines with alcohols for N-alkylated amines has been developed using inexpensive AlCl3without any ligand or additive.Either aromatic or aliphatic amines and primary or secondary alcohols per...A substitution reaction of amines with alcohols for N-alkylated amines has been developed using inexpensive AlCl3without any ligand or additive.Either aromatic or aliphatic amines and primary or secondary alcohols perform the AlCl3-mediated reaction smoothly to afford various N-alkylated amines in satisfactory yields.展开更多
基金supported by National Natural Science Foundation of China(Nos.51988102,22271275,22201280,22101277)Special Project of High-tech Industrialization of Cooperation between Jilin Province and Chinese Academy of Sciences(No.2022SYHz0004)Changchun Science and Technology Development Plan Funding Project(No.21ZY10).
文摘Ring-opening copolymerization of CO_(2) and epoxides is a promising way to manufacture high value-added materials.Despite a variety of catalyst systems have been reported,the reaction is still limited by low activity and polymer selectivity.Herein,a strategy of polymerization-enhanced Lewis acidity is reported to construct a series of highly efficient polymeric aluminum porphyrin catalysts(PAPCs).The characterization of the coordination equilibrium constant(K_(eq))showed significantly enhanced Lewis acidity of PAPC(K_(eg)=18.2 L/mol)compared to the monomeric counterpart(K_(eq)=6.4 L/mol),accompanied with increased turnover frequency(TOF)from 136 h^(-1) to 5500 h^(-1).Through detailed regulation of Lewis acidity,the highly Lewis acidic PAPC-OTs displayed a record high TOF of 30,200 h^(-1) with polymer selectivity of up to 99%.
基金supported by the National Natural Science Foundation of China (NSFC,Nos.12474274,92161101)the Innovation Project of Jinan Science and Technology Bureau (No.2021GXRC032)the Natural Science Foundation of Shandong Province (No.ZR2024MA091)。
文摘The Jellium closed-shell model,a cornerstone of cluster science,has long guided the design of superatoms by dictating electron-counting rules.However,its reliance on precise control of cluster composition and electron shell occupancy presents significant experimental challenges.Here,we introduce a ligation strategy that circumvents these limitations by demonstrating that the adiabatic electron affinity(AEA) of aluminum-based clusters,whether with filled or partially filled electron shells,can be dramatically enhanced through the attachment of organic Lewis acid ligands.It was evidenced that the AEA of PAl12can be significantly increased by 2.17 e V after the ligation of two ligands,indicating a remarkable improvement in its electron-accepting ability.This approach yields superhalogen species,offering a versatile and practical means to tune the electronic properties of clusters while preserving their superatomic states,independent of shell occupancy.Remarkably,this ligand-induced modulation is not confined to naked clusters but also extends to nano-confined systems,hinting at its broader applicability.Given the indispensable role of ligands in cluster synthesis,this strategy holds promise for advancing the field of condensed-phase superatom synthesis,potentially complementing traditional electron-counting rules in a broader range of applications.
基金supported by the National Natural Science Foundation of China (21576262, 21206169)International S&T Cooperation Program of China (2014DFA61670)the “Recruitment of Outstanding Technologist” of Chinese Academy of Sciences
文摘It is urgent to develop a new deep desulfurization process of fuels as the environmental pollution increases seriously. In this work, a series of Lewis acidic ionic liquids （ILs） [C43MPy]Cl/nZnCl2 （n=1, 1.5, 2, 3） were synthesized and used in extraction and catalytic oxidative desulfurization （ECOD） of the fuels. The effects of the Lewis acidity of ILs, the molar ratio of H2O2/sulfur, temperatures, and different substrates including dibenzothiophene （DBT）, benzothiophene （BT） and thiophene （TS）, on sulfur removal were investigated. The results indicated that [C43MPy]Cl/3ZnCl2 presented near 100% DBT removal of model oil under conditions of 323 K, H2O2/DBT molar ratio 6：1. Kinetics for the removal of DBT, BT and TS by the [C43MPy]Cl/3ZnCl2-H2O2 system at 323 K is first-order with the apparent rate constants of 1.1348, 0.2226 and 0.0609 h-1, and the calculated apparent activation energies for DBT, BT and TS were 61.13, 60.66, and 68.14 kJ/mol from 298 to 308 K, re- spectively. After six cycles of the regenerated [C43MPy]Cl/3ZnCl2, the sulfur removal had a slight decrease. [C43MPy]Cl/ 3ZnCl2 showed a good desulfurization performance under optimal conditions.
基金supported by the National Natural Science Foundation of China(51802252)Natural Science Foundation of Shaanxi Province(2020JM-032)+1 种基金Natural Science Foundation of Jiangsu Province(BK20180237)111 Project 2.0(BP0618008)。
文摘The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material structure.In this study,we prepared a novel Sn S_(2)/black phosphorus(BP)two-dimensional(2D)-2D heterostructure via the in situ hydrothermal growth of Sn S_(2)nanosheets on exfoliated BP lamellae for NO_(2)sensing applications.In the Sn S_(2)/BP composite,the holes with high oxidizability in p-type BP could oxidize Sn^(2+)into Sn^(4+),thus inhibiting the formation of Lewis acidic S vacancies.This Sn^(2+)/Lewis acidity suppression of the composite was further confirmed by X-ray photoelectron spectroscopy and acidic double-layer capacitance analyses,and promoted the adsorption and detection of acidic NO_(2).Owing to its valence and Lewis acidity engineering,the Sn S_(2)/BP heterostructure sensor could detect trace levels of NO_(2)as low as 100 ppb(parts per billion)with high response,fast response/recovery,good stability,and selectivity at room temperature.The high absorption energy of NO_(2)(à0.74 e V),as indicated by the density functional theory calculations,suggests that NO_(2)was chemically adsorbed on the Sn S_(2)/BP surface,which was also evidenced by the in situ Raman spectroscopy results.This work opens up interesting opportunities for the rational design of highly efficient NO_(2)gas sensors through Lewis acidity modification and interface engineering.
基金Project supported by the National Natural Science Foundation of China.
文摘The Lewis acidity scale of boron trihalides BX3 (X=F, Cl, Br, I) and character of the boron-halogen bonds have been studied by means of DV-Xa approach. Present results show that the acid strength of boron trihalides increases in the order BF3<BCl3<BBr3<BI3, in excellent agreement with experiments. Based on boron-halogen bonding character, the valence of boron atom in boron compounds can be considered as equal to five instead of three which seems to be more reasonable.
基金financial support from the National Natural Science Foundation of China(52372173,52072034)。
文摘Direct electrolysis of seawater offers a transformative technology for sustainable hydrogen production,circumventing the constraint of freshwater scarcity.However,the serious electrode corrosion and competitive chloride oxidation reactions make oxygen evolution reaction(OER)in seawater extremely challenging.Herein,the low-cost and scalable CoFe layered double hydroxides with Cl^(-)intercalation and decorated with Ce(OH)_(3)(named as CoFe-Cl^(-)/Ce(OH)_(3))catalyst is synthesized via rapid electrodeposition under ambient conditions,which is quickly reconstructed into a CeO_(2)decorated and Cl^(-)intercalated CoFeOOH(CoFeOOH-Cl^(-)/CeO_(2))during OER.Theoretical investigation reveals that Cl^(-)intercalation weakens the adsorption ability of Cl^(-)on Co/Fe atoms and hinders unfavorable coupling with chloride,thereby preventing the chlorine corrosion process and enhancing catalytic stability and activity.The CeO_(2)with hard Lewis acidity preferentially binds to OH-with harder Lewis base to ensure the OH-rich microenvironment around catalyst even under high current operating conditions,thus further enhancing stability and improving OER activity.The functionalized CoFe-Cl^(-)/Ce(OH)_(3)delivers 1000 mA cm^(-2)current density at only 329 mV overpotential with excellent stability for 1000 h under alkaline seawater.Electrochemical experiments elucidate the OER catalytic mechanism in which CeO_(2)serves as a co-catalyst for enriching OH-and CoFeOOH-Cl^(-)is the active species.Our work is a substantial step towards achieving massive and sustainable production of hydrogen fuel from immense seawater.
基金Fundamental Research Foundation of CAF (CAFYBB2022QB001)National Nature Science Foundation of China for Excellent Young Scientists Fund (32222058)。
文摘The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electronic structure. Here, a nickel-based transition metal carbide catalyst(Ni/TMC) with high Lewis acidity was prepared by self-assembly of transition metal carbide(TMC) and nickel, which exhibited excellent performance on synergistic hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural(HMF) into liquid biofuel 2,5-dimethylfuran(DMF).Notably, Ni/WC with the highest Lewis acidity(4728.3 μmol g^(-1)) can achieve 100% conversion of HMF to 97.6% yield of DMF, with a turnover frequency of up to 46.5 h^(-1). The characterization results demonstrate that the rich Lewis acid sites yielded by the synergistic effect between Ni species and TMC are beneficial for the C=O hydrogenation and C–O cleavage, thereby accelerating the process of hydrodeoxygenation(HDO). Besides, a kinetic model for the HDO of HMF to DMF process has been established based on the experimental results, which elucidated a significant correlation between the measured and the predicted data(R^(2)> 0.97). Corresponding to the adsorption configuration of Ni/WC and substrate determined by in-situ FTIR characterization, this study provides a novel insight into the selective conversion of HMF process for functional biofuel and bio-chemicals.
基金supported by the National Natural Science Foundation of China(No.52201274)the Project of Education Department of Shanxi Province(No.22JK0419).
文摘High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kinetics.To solve the above problems,it is proposed to enhance the hydrogen storage properties of LiBH_(4)through the synergistic effect of Brønsted and Lewis acid in Hβzeolite.Composite hydrogen storage systems with different mass ratios were prepared by simple ball-milling.At a LiBH_(4)-to-Hβmass ratio of 6:4,the 6LiBH_(4)-4Hβsystem released hydrogen at 190℃and achieved a hydrogen release capacity of 7.0 wt%H_(2)upon heating to 400℃.More importantly,the hydrogen release capacity of the system reached 6.02 wt%at 350℃under isothermal conditions after 100 min and 7.2 wt%at 400℃under isothermal conditions after 80 min,whereas the pristine LiBH_(4)only achieved 2.2 wt%.The improvement in hydrogen storage performance of the system was mainly attributed to two factors:(i)Lewis acid sites with acceptable electrons in the Hβweaken the electron density of B-H bonds in LiBH_(4),and(ii)the H+proton from the Brønsted acid sites and H−of LiBH_(4)undergo a H^(+)+H^(−)=H_(2)reaction.Theoretical calculations revealed that the Lewis and Brønsted acid sites in the Hβzeolite are conducive to the weakening of B-H bonds and that storage charge transfer occurs near the Lewis acid sites.The present work provides new insights into improving the hydrogen storage performance of LiBH_(4)by weakening the B-H bonds in the LiBH_(4).
基金the grant from the National Natural Science Foundation of China （Key Program 20533010）.
文摘Novel Lewis acidic ionic liquids containing thionyl cations and chloroaluminate anions were obtained by one-pot synthesis for the first time. Their acidities were determined by acetonitrile probe on IR spectrography. The ionic liquids were used as catalyst for Friedel-Crafts alkylation of benzene and 1-dodecene. The turnovers of l-dodecene were higher than 99%. Monoalkylbenzene selectivity was 98%, while the 2-substituent product selectivity was 45%.
基金the National Natural Science Foundation of China(Nos.U1462106 and 21673076)the National Key Research and Development Program of China(No.2016YFB0701100)
文摘Avery wide range of the C3^=/C2^= ratio from 0.72 to 7.56 with high C2^= ＋ C3^= selectivity of around 66%in the methanol-to-hydrocarbons process can be realized over ZSM-5 catalyst in a fixed-bed reactor.We firstly conduct a single factor experiment of acidity,demonstrating that the acidity control of MTH catalyst is crucial to adjusting light olefins selectivity.Weak Bronsted acid sites favor to high C3^= selectivity（59.0%）due to the suppression of the conversion reactions from the alkene-based to arene-based cycle,while Lewis acid sites conduce to high C2^= selectivity（39.6%） due to the promotion of the conversion reactions for the aromatics formation and steric constraints of Lewis acid sites making the aromatics crack more efficiently to C2^=.
基金the financial support from the National Natural Science Foundation of China(52172110,52472231,52311530113)Shanghai"Science and Technology Innovation Action Plan"intergovernmental international science and technology cooperation project(23520710600)+1 种基金Science and Technology Commission of Shanghai Municipality(22DZ1205600)the Central Guidance on Science and Technology Development Fund of Zhejiang Province(2024ZY01011)。
文摘Investigating structural and hydroxyl group effects in electrooxidation of alcohols to value-added products by solid-acid electrocatalysts is essential for upgrading biomass alcohols.Herein,we report efficient electrocatalytic oxidations of saturated alcohols(C_(1)-C_(6))to selectively form formate using Ni Co hydroxide(Ni Co-OH)derived Ni Co_(2)O_(4)solid-acid electrocatalysts with balanced Lewis acid(LASs)and Brønsted acid sites(BASs).Thermal treatment transforms BASs-rich(89.6%)Ni Co-OH into Ni Co_(2)O_(4)with nearly equal distribution of LASs(53.1%)and BASs(46.9%)which synergistically promote adsorption and activation of OH-and alcohol molecules for enhanced oxidation activity.In contrast,BASs-enriched Ni Co-OH facilitates formation of higher valence metal sites,beneficial for water oxidation.The combined experimental studies and theoretical calculation imply the oxidation ability of C1-C6alcohols increases as increased number of hydroxyl groups and decreased HOMO-LUMO gaps:methanol(C_(1))<ethylene glycol(C_(2))<glycerol(C3)<meso-erythritol(C4)<xylitol(C5)<sorbitol(C6),while the formate selectivity shows the opposite trend from 100 to 80%.This study unveils synergistic roles of LASs and BASs,as well as hydroxyl group effect in electro-upgrading of alcohols using solid-acid electrocatalysts.
基金supported by the Highstar Corporation HSD20210118Taihu Electric Corporation 0001。
文摘Since the discovery in 2011,MXenes have become the rising star in the field of two-dimensional materials.Benefiting from the metallic-level conductivity,large and adjustable gallery spacing,low ion diffusion barrier,rich surface chemistry,superior mechanical strength,MXenes exhibit great application prospects in energy storage and conversion,sensors,optoelectronics,electromagnetic interference shielding and biomedicine.Nevertheless,two issues seriously deteriorate the further development of MXenes.One is the high experimental risk of common preparation methods such as HF etching,and the other is the difficulty in obtaining MXenes with controllable surface groups.Recently,Lewis acidic etching,as a brand-new preparation strategy for MXenes,has attracted intensive attention due to its high safety and the ability to endow MXenes with uniform terminations.However,a comprehensive review of Lewis acidic etching method has not been reported yet.Herein,we first introduce the Lewis acidic etching from the following four aspects:etching mechanism,terminations regulation,in-situ formed metals and delamination of multi-layered MXenes.Further,the applications of MXenes and MXene-based hybrids obtained by Lewis acidic etching route in energy storage and conversion,sensors and microwave absorption are carefully summarized.Finally,some challenges and opportunities of Lewis acidic etching strategy are also presented.
基金financial support of the National Natural Science Foundation of China (Grant No. 21263016, 21363015, 51662029, 21863006)the Youth Science Foundation of Jiangxi Province (Grant No. 20192BAB216001)the Key Laboratory of Jiangxi Province for Environment and Energy Catalysis (20181BCD40004)。
文摘Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of carbon.Herein, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).
基金supported by the National Key R&D Program of China (No. 2016YFE0112800)the European Union’s Horizon 2020 research and innovation programme (No. 690142)+1 种基金the project Agro Cycle (Sustainable techno-economic solutions for the agricultural value chain)the National Natural Science Foundation of China (No. 31671572)
文摘An experimental investigation was conducted to understand the roles of the Br？nsted acid H2SO4 and Lewis acid Al2（SO4）3 in methyl levulinate（ML） production from biomass carbohydrates, including glucose,fructose and cellulose. The product distributions with different catalysts revealed that the Lewis acid was responsible for the isomerization of methyl glucoside（MG）, producing a significant amount of the subsequent product 5-methoxymethylfurfural（MMF）, while the Br？nsted acid facilitated the production of ML from MMF. Al2（SO4）3 was efficient for monosaccharide conversion but not for cellulose. Using ball-milled cellulose with Al2（SO4）3 resulted in a desired ML yield within a reasonable reaction time. The significant catalysis performances of two types of acids will guide the design of efficient catalytic processes for the selective conversion of biomass into levulinate esters.
文摘The self-aldol condensation of aldehydes was investigated with rare-earth cations stabilized by[Si]Beta zeolites in parallel with bulk rare-earth metal oxides.Good catalytic performance was achieved with all Lewis acidic rare-earth cations stabilized by zeolites and yttrium appeared to be the best metal choice.According to the results of several complementary techniques,i.e.,temperature-programmed surface reactions,in situ diffuse reflectance infrared Fourier transform spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,the reaction pathway and mechanism of the aldehyde self-aldol condensation over Y/Beta catalyst were studied in more detail.Density functional theory calculations revealed that aldol dehydration was the rate-limiting step.The hydroxyl group at the open yttrium site played an important role in stabilizing the transition state of the aldol dimer reducing the energy barrier for its hydration.Lewis acidic Y(OSi)(OH)2 stabilized by zeolites in open configurations were identified as the preferred active sites for the self-aldol condensation of aldehydes.
基金supported by the National Natural Science Foundation of China (21973013 and 21673040 to S.L, and 21962007 to S.Z)the Natural Science Foundation of Fujian Province of China (2020J02025 to S.L)+2 种基金the Natural Science Foundation of Jiangxi Province (2020BABL203009 to S.Z)the Foundation of Jiangxi Educational Committee (GJJ190697 to S.Z)the Qishan Scholarship Program of Fuzhou University (XRC-17055 to S.L)。
文摘CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ceria catalysts for NRR remains a challenge due to the poor knowledge of the catalytic mechanism, particularly the nature of the active sites and how they catalyze NRR. Here, using first-principle calculations, we investigated the NRR catalysis process involving adjacent Ce Lewis acid clusters formed on(111),(110), and(100) facets of CeO_(2) as active sites. Our results revealed that the assembled structures of the Ce Lewis acid as active centers after the oxygen vacancies(Ovs) were opened. The exposed Ce sites on CeO_(2)(111), CeO_(2)(110), and CeO_(2)(100) can cause N_(2) to be adsorbed in a ‘‘lying-down" manner, which facilitates the N2 activation and thus leads to much higher NRR activity. Furthermore, from the perspective of electronic structure, we establish two useful descriptors for assessing the NRR activity on ceria with Ovs:The N–N bond strength of the adsorbed N_(2) and the adsorption energy of the *N_(2)H intermediate. This work thus provides direct guidance for the design of more-effective oxide catalysts without the use of scarce metals.
文摘The azides were reduced to the corresponding amines by two new metal/Lewis acid systems in water or in aqueous EtOH in yields ranging from 80%-95%. The reaction rates were faster in water than in aqueous EtOH in most cases. All 16 azides with different functional groups were well reduced to the corresponding amines in excellent yields and reaction rates.
基金the National Science Foundation for Excellent Young Scholars of China(21922815)the Key Research and Development(R&D)Projects of Shanxi Province(201903D121007)+3 种基金the Natural Science Foundations of Shanxi Province(201801D221156)the DNL Cooperation Fund of CAS(DNL180308)the Science and Technology Service Network Initiative of CAS(KFJ-STS-ZDTP-068)the Youth Innovation Promotion Association of CAS。
文摘The incorporation of boron into carbon material can significantly enhance its capacity performances.However,the origin of the promotion effect of boron doping on electrochemical performances is still unclear,in part due to the inadequate exposure of boron configurations resulting from the complexity of traditional carbon materials.To overcome this issue,herein,a series of boron-doped graphene with highly-exposed boron configurations are prepared by tuning annealing temperature.Then the correlation between boron configurations and the electrochemical performances is investigated.The combination of density-functional theory(DFT)computation and NH3-TPD/Py-FTIR indicates that the BCO_(2)configuration formed on the surface of graphene is easier to accept lone-pair electrons than BC_(2)O and BC_(3)configurations due to the stronger Lewis acidity.Such an electronic structure can effectively reduce the number of unstable electron donors and stabilize the electrochemical interface,which is proved by NMR,and critical for improving the electrochemical performances.Further experiments confirm that the optimized BG800 with the largest amount of BCO_(2)configuration presents ultralow leak current,improved cyclic stability,and better rate performance in SBPBF4/PC.This work would provide an insight into the design of high-performance boron-doped carbon materials towards energy storage.
基金A Project Funded by Jiangsu Natural Science Foundation of China(No.BK2011369)
文摘Lewis acidic ionic liquids were used to catalyze the reaction of epoxypropane with POCl3. Considering the lower cost and catalytic activities, we concluded that [Et3NH]Cl/AlCl3 was the most attractive ionic liquid from an economical point of view. But it would be easily inactivated because of sensitive to water and air. Moreover, it could not be reused easily because of difficulty recovery in the reaction. However, supporting [Et3NH]Cl/AlCl3 catalyst could resolve above problems. Supporting [Et3NH]Cl/ AlCl3 catalyst could be separated by filter easily and reused 5 times in 98% yield. Furthermore, the catalyst was applicable to other epoxy ether cleaving reactions.
基金Financial supports from MOST of China(973 program,No. 2011CB808600)National Natural Science Foundation of China(Nos.21072091 and 21372195)the Low Carbon Fatty Amine Engineering Research Center of Zhejiang Province(No. 2012E10033)
文摘A substitution reaction of amines with alcohols for N-alkylated amines has been developed using inexpensive AlCl3without any ligand or additive.Either aromatic or aliphatic amines and primary or secondary alcohols perform the AlCl3-mediated reaction smoothly to afford various N-alkylated amines in satisfactory yields.
