A multi-stimuli-responsive hydrogel,P(VI-co-MAAC-NE),was successfully constructed by covalently integrating the aggregation-induced emission(AIE)moiety(Z)-N-(4-(1-cyano-2-(4-(diethylamino)phenyl)vinyl)-phenyl)methacry...A multi-stimuli-responsive hydrogel,P(VI-co-MAAC-NE),was successfully constructed by covalently integrating the aggregation-induced emission(AIE)moiety(Z)-N-(4-(1-cyano-2-(4-(diethylamino)phenyl)vinyl)-phenyl)methacrylamide(NE)into a dynamic hydrogen-bonding network composed of 1-vinylimidazole(VI)and methacrylic acid(MAAC)groups.The dense hydrogen-bonding network not only provides enhanced mechanical robustness,but also significantly enhances the AIE effect of NE by restricting its molecular motion.Under various external stimuli,the hydrogen bonds within the hydrogel network undergo reversible dissociation and reformation,thus enabling synergistic modulation of the hydrogel’s mechanical properties and luminescence behavior.Specifically,organic solvents disrupt the hydrogen-bonding network and the aggregation of the AIE moiety NE,resulting in macroscopic swelling and fluorescence quenching of the hydrogel.In strongly acidic conditions,protonation of NE molecules suppresses the intramolecular charge transfer(ICT)process,yielding a blue-shifted emission band accompanied by intense blue fluorescence;in highly alkaline environments,deprotonation of carboxyl groups induces hydrogel swelling and disperses NE aggregates,leading to pronounced fluorescence quenching.Moreover,the system exhibits thermally activated shape-memory behavior:heating above the glass transition temperature(T_(g):ca.62℃)softens the hydrogel to allow programmable reshaping,and subsequent hydrogen bond reformation at ambient conditions locks in the resultant geometries without sacrificing the hydrogel’s fluorescence performance.By capitalizing on these multi-stimuli-responsive characteristics and shape-memory behavior,the potential of hydrogel P(VI-co-MAAC-NE)for advanced information encryption and anti-counterfeiting applications is demonstrated.This work not only provides a versatile material platform for sensing and information storage,but also offers new insights into the design of intelligent soft materials integrating AIE features with dynamically regulated supramolecular network structures.展开更多
Aqueous Zn-metal batteries(AZMBs)performance is hampered by freezing water at low temperatures,which hampers their multi-scenario application.Hydrogen bonds(HBs)play a pivotal role in water freezing,and proton transpo...Aqueous Zn-metal batteries(AZMBs)performance is hampered by freezing water at low temperatures,which hampers their multi-scenario application.Hydrogen bonds(HBs)play a pivotal role in water freezing,and proton transport is indispensable for the establishment of HBs.Here,the accelerated proton transport modulates the dynamic hydrogen bonding network of a Zn(BF4)2/EMIMBF4impregnated polyacrylamide/poly(vinyl alcohol)/xanthan gum dual network eutectic gel electrolyte(PPX-ILZSE)for lowtemperature AZMBs.The PPX-ILZSE forms more HBs,shorter HBs lifetimes,higher tetrahedral entropy,and faster desolvation processes,as demonstrated by experimental and theoretical calculations.This enhanced dynamic proton transport promotes rapid cycling of HBs formation-failure,and for polyaniline cathode(PANI)abundant redox sites of proton,confers excellent low temperature electrochemical performance to the Zn//PANI full cell.Specific capacities for 1000 and 5000 cycles at 1 and 5 A g^(-1)were149.8 and 128.4 m A h g^(-1)at room temperature,respectively.Furthermore,specific capacities of 131.1 mA hg^(-1)(92.4%capacity retention)and 0.0066%capacity decay per lap were achieved for 3000and 3500 laps at-30 and 40℃,respectively,at 0.5 A g^(-1).Furthermore,in-situ protective layer of ZnOHF nano-arrays on the Zn anode surface to eliminate dendrite growth and accelerate Zn-ions adsorption and charge transfer.展开更多
In this paper, the hydrogen bonding network models of konjac glucomannan （KGM） are predicted in the approach of molecular dynamics （MD）. These models have been proved by experiments whose results are consistent wi...In this paper, the hydrogen bonding network models of konjac glucomannan （KGM） are predicted in the approach of molecular dynamics （MD）. These models have been proved by experiments whose results are consistent with those from simulation. The results show that the hydrogen bonding network structures of KGM are stable and the key linking points of hydrogen bonding network are at the O（6） and O（2） positions on KGM ring. Moreover, acety has significant influence on hydrogen bonding network and hydrogen bonding network structures are more stable after deacetylation.展开更多
Hydrothermal reaction of MgCl2 and ethyl tetrazolate-5-carboxylate at 160 ℃unexpectedly yielded compound {（H3O）[Mg（H2O）6]Cl3} （1）. The result of X-ray diffraction analysis indicates that 1 crystallizes in the m...Hydrothermal reaction of MgCl2 and ethyl tetrazolate-5-carboxylate at 160 ℃unexpectedly yielded compound {（H3O）[Mg（H2O）6]Cl3} （1）. The result of X-ray diffraction analysis indicates that 1 crystallizes in the monoclinic system, space group C2/c with a = 9.2896（3）, b = 9.5570（4）, c = 13.3169（5） A, β = 90.1221（12）°, V= 1182.28（8） A3, Z = 4, Mr = 257.78, Dc = 1.448 g/cm3, μ = 0.824 mm^-1, F（000） = 536, R = 0.0265 and wR - 0.0706. 1 is composed of one hexa-aqua-magnesium（Ⅱ） ion, one hydroxonium ion, and three chlorine anions. These three components weave a perfect three-dimensional （3D） （4,4,6,12）-connected hydrogen bonding network within 1.展开更多
A series of inorganic acids were introduced into the self-assembly with the bent 2,5-bis(4-pyridyl)-1,3,4-oxadiazole(4-bpo),yielding seven anion-assisted supramolecular salts,i.e.[(4-H_(2)bpo^(2+))·(NO_(3)^(−))_(...A series of inorganic acids were introduced into the self-assembly with the bent 2,5-bis(4-pyridyl)-1,3,4-oxadiazole(4-bpo),yielding seven anion-assisted supramolecular salts,i.e.[(4-H_(2)bpo^(2+))·(NO_(3)^(−))_(2)]·2H_(2)O(1),(4-H_(2)bpo^(2+))·(HPO_(4)^(2−))(2),[(4-H_(2)bpo^(2+))_(2)·(4-Hbpo^(+))·(I_(3)^(−))_(3)·(I^(−))_(2)]·2H_(2)O(3),[(4-Hbpo^(+))_(2)·(PF_(6)^(−))_(2)]·H_(2)O(4),[(4-H_(2)bpo^(2+))·(BF_(4)^(−))_(2)]·H_(2)O(5),[(4-Hbpo^(+))·(BF_(4)^(−))](6)and(4-H_(2)bph^(2+))·(SO_(4)^(2−))(7).Structural analyses indicate that different inorganic anions(e.g.spherical,linear,trigonal planar,tetrahedral and octahedral)can induce the formation of diverse supramolecular architectures,influencing the crystallization ratio,the protonated number and the final structure.The anions are hydrogen bonded to the angular dipyridine,which offers a sufficient driving force for the directed assembly of supramolecular hydrogen-bonding frameworks.Thereto,various hydrogen-bonding motifs are observed in all these cases(1–7)and the nitrogen atoms of pyridines are protonated apart from salt 6.Among them,salts 1,3,4 and 5 crystallize with water molecules but the others do not.Interestingly,appealing substructures have been generated by anions and water molecules in 1,3 and 5 but not in 4.HPO_(4)^(2−)dimers form in 2 despite there being no assistance from solvent water.BF_(4)^(−)anions facilitate the formation of the helical chain in 6.Unexpectedly,the oxadiazole ring opened via the in situ hydrolysis under hydrothermal conditions during crystallization with H_(2)SO_(4),producing salt 7.展开更多
Expanded polytetrafluoroethylene(e-PTFE)reinforced perfluorosulfonic acid(PFSA)is the predominant proton exchange membrane(PEM)for hydrogen fuel cells.However,the difference in interfacial properties between PFSA and ...Expanded polytetrafluoroethylene(e-PTFE)reinforced perfluorosulfonic acid(PFSA)is the predominant proton exchange membrane(PEM)for hydrogen fuel cells.However,the difference in interfacial properties between PFSA and e-PTFE significantly decreases the proton conduction efficiency and durability of the PEM.In this study,the polyphenolamine treatment method(TA)is employed to effectively enhance the hydrophilicity and interfacial compatibility of e-PTFE,as well as to functionalize the surface of the free radical scavenger ZrO_(2) filler.The surface of the modified e-PTFE and ZrO_(2) is rich in polar phenolic hydroxyl groups and amino groups,which effectively enhance the three-dimensional interface compatibility of the e-PTFE/PFSA reinforced composite membrane(RCM),and improve the proton conductivity by establishing a three-dimensionally-reinforced hydrogen bonding network.The proton conductivity of the RCM is 0.203 S cm^(-1) at 80℃,and the tensile strength is 50.7 MPa.The peak power density of the hydrogen fuel cell based on the composite membrane is 1.46 W cm^(-2) at 80℃ and 50%RH.Moreover,the durability of the composite membrane is considerably improved by the redox properties of the surface functional groups of e-PTFE and the valence-changing properties of ZrO_(2).Following a 72-hour Fenton reaction,the mass loss of the TA@ZrO_(2)/e-PTFE RCM was found to be only 13.5%.The accelerated durability test indicates that the TA@ZrO_(2)/e-PTFE RCM can still provide a current density of 1.3 A cm^(-2) after 5500 dry/wet cycles at 0.55 V.展开更多
As an earth-abundant and natural biopolymer,cellulose has received significant attention in aqueous zinc-ion batteries(AZIBs)due to its inherent sustainability and non-toxicity,aligning perfectly with the core advanta...As an earth-abundant and natural biopolymer,cellulose has received significant attention in aqueous zinc-ion batteries(AZIBs)due to its inherent sustainability and non-toxicity,aligning perfectly with the core advantages of AZIBs.Nevertheless,the practical implementation of cellulose-based materials is limited by their intrinsically low ionic conductivity.Herein,we introduce a novel zincophilic artificial protective layer by strategically hybridizing hydroxypropyl cellulose(HPC)with zinc trifluoromethanesulfonate on a zinc metal anode(HZ@Zn).Characterization and calculations demonstrate that the multihydroxyl architecture of HPC constructs hydrogen bond networks,whereas the Zn^(2+)-coordinated HPC domains function as preferential nucleation sites for zinc deposition.These interactions collectively enhance ion transport and accelerate desolvation kinetics.Additionally,the hybrid layer's mechanical flexibility and interfacial adhesion ensure the integrity of the artificial protective layer during long cycling.Thanks to this synergistic effect,HZ@Zn shows exceptional electrochemical performance,including a low desolvation activation energy of 14.38 kJ mol^(-1)and ultra-long cycling stability.Symmetric cells demonstrate exceptional longevity,exceeding 9,500 h at 0.5 mA cm^(-2)/0.25 mAh cm^(-2),whereas HZ@Zn‖PANI full cells maintain 89.8%capacity retention after 4000 cycles at 5 A g^(-1).This study establishes biopolymers as versatile platforms for effectively stabilizing the zinc metal anode.展开更多
The development of membranes featuring carbon nanotubes(CNTs)have provided possibilities of next-generation solar desalination technologies.For solar desalination,the microstructures and interactions between the filte...The development of membranes featuring carbon nanotubes(CNTs)have provided possibilities of next-generation solar desalination technologies.For solar desalination,the microstructures and interactions between the filter membrane and seawater play a crucial role in desalination performance.Understanding the mechanisms of water evaporation and ion rejection in confined pores or channels is necessary to optimize the desalting process.Here,using non-equilibrium molecular dynamics simulations,we found that continuous water-water hydrogen bonding network across the rims of CNTs is the key factor in facilitating water transport through CNTs.With the continuous hydrogen bonding network,the water flux is two times of that without the continuous hydrogen bonding network.In CNT arrays,each CNT transports water molecules and rejects salt ions independently.Based on these observations,using CNT arrays consisted with densely packed thin CNTs is the most advisable strategy for evaporation desalination,possessing high transport flux as well as maintaining high salt rejection.展开更多
Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further developme...Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further development.Herein,potassium acetate(KAc) additive with cation/anion synergy effect is added into the ZnSO_(4) electrolyte to effectively promote the oriented uniform Zn deposition and suppress side reactions.According to density functional theory calculation and experimental results,CH_(3)COO^(-)(Ac^(-))anions are capable of forming stronger hydrogen bonds with H_(2)O molecules,leading to an expanded electrochemical stability window,reduced the reactivity of H_(2)O,and hence suppressing HER.Meanwhile,Ac-anions can also preferentially adsorb onto the Zn anode,promoting dense deposition towards the(100) crystal plane.Besides,dissociated K^(+) ions serve as electrostatic shielding cations,which significantly promote uniform Zn deposition and prevent dendrite formation.Thus,the Zn||Zn symmetric cell demonstrates an impressive cycle lifespan of 3000 h at 1.0 m A/cm^(2).Furthermore,the Zn||MnO_(2) full battery exhibits superior stability with a capacity retention of 86.95 % at 2.0 A/g after 4000 cycles.Therefore,the cation/anion synergy effect in KAc additive offers a viable solution to address HER and hinder dendrite growth at the interface of Zn anodes.展开更多
Aqueous alkali metal-ion batteries(AAMIBs)have been recognized as emerging electrochemical energy storage technologies for grid-scale applications owning to their intrinsic safety,cost-effectiveness,and environmental ...Aqueous alkali metal-ion batteries(AAMIBs)have been recognized as emerging electrochemical energy storage technologies for grid-scale applications owning to their intrinsic safety,cost-effectiveness,and environmental sustainability.However,the practical application of AAMIBs is still severely constrained by the tendency of aqueous electrolytes to freeze at low temperatures and decompose at high temperatures,limiting their operational temperature range.Considering the urgent need for energy systems with higher adaptability and resilience at various application scenarios,designing novel electrolytes via structure modulation has increasingly emerged as a feasible and economical strategy for the performance optimization of wide-temperature AAMIBs.In this review,the latest advancement of wide-temperature electrolytes for AAMIBs is systematically and comprehensively summarized.Specifically,the key challenges,failure mechanisms,correlations between hydrogen bond behaviors and physicochemical properties,and thermodynamic and kinetic interpretations in aqueous electrolytes are discussed firstly.Additionally,we offer forward-looking insights and innovative design principles for developing aqueous electrolytes capable of operating across a broad temperature range.This review is expected to provide some guidance and reference for the rational design and regulation of widetemperature electrolytes for AAMIBs and promote their future development.展开更多
Based on the knot theory and researching of network structures of glucomannan molecules, the polysaccharides were analyzed. The link prediction analysis is to further reveal the interactions between polysaccharides, t...Based on the knot theory and researching of network structures of glucomannan molecules, the polysaccharides were analyzed. The link prediction analysis is to further reveal the interactions between polysaccharides, to elaborate QSAR of polysaccharides, and to analyze the network conformation relationships among polysaccharides. We made a classification for glucomannan molecules based on the related domestic and international theories, and investigated their network structures and application prospects. The knot theory and the link predictions not only simplify the glucomannan microscopic descriptions but also play a guiding role in predicting and regulating the structures.展开更多
The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of society.Since the existence of dynamic chemical bonds in vitrimers often reduces both the ther...The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of society.Since the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine solution.This study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.展开更多
Two crystals of receptor 1, C（42）H（52）N（10）O4S2（anthracene-9,10-dicarbaldehyde bis-（phenyl-semithiocarbazone）） and-1-H2PO4, C（68）H（114）N（10）O（10）P2S2 were obtained at room temperature successfully, a...Two crystals of receptor 1, C（42）H（52）N（10）O4S2（anthracene-9,10-dicarbaldehyde bis-（phenyl-semithiocarbazone）） and-1-H2PO4, C（68）H（114）N（10）O（10）P2S2 were obtained at room temperature successfully, and their structures were characterized by X-ray crystallography diffraction. X-ray diffraction reveals that, receptor 1 crystallizes in monoclinic, space group P21/c, with a = 9.487（3）,b = 20.674（6）, c = 11.821（4）A, β = 113.416（8）o, Mr = 825.06, V = 2127.5（12） A^3, Z = 2, Dc = 1.288g/cm^3, μ = 0.18 mm^-1, F（000） = 876, MoK α radiation（λ = 0.71073 A）, the final R = 0.0472 and wR = 0.0930. A total of 3758 unique reflections were collected, of which 3313 with I 〉 2σ（I） were observed. Compound 1-H2PO4^-crystallizes in triclinic, space group P21/n, with a = 8.767（1）, b =13.6190（15）, c = 16.615（2） ？, α = 98.727（14）, β = 103.061（14）, γ = 91.382（16）°, Mr = 1357.75, V =1906.6（4） A^3, Z = 1, Dc = 1.183 g/cm^3, μ = 0.17 mm-（-1）, F（000） = 734, MoK α radiation（λ = 0.71073？）, the final R = 0.0769 and wR = 0.1884. A total of 6699 unique reflections were collected, of which 2989 with I 〉 2σ（I） were observed. As it was observed in the crystal structure of 1-H2PO4^-, 1bound H2PO4^-at a 1：2 ratio by intermolecular interaction of N-H···O hydrogen bond obviously.Another interesting feature was that H2PO4--groups assembled chains themselves via intramolecular hydrogen bond O-H···O and connected the 1 molecules together through the interaction of H-bonds,which improved the planarity of 1 and increased the stability of the entire structure.展开更多
A“water”accelerated metal-free catalytic system has been discovered for the Mukaiyama-aldol reaction.The system involves the use of B(C_(6)F_(5))_(3) as a catalyst,which is water-tolerant and able to activate the ca...A“water”accelerated metal-free catalytic system has been discovered for the Mukaiyama-aldol reaction.The system involves the use of B(C_(6)F_(5))_(3) as a catalyst,which is water-tolerant and able to activate the carbonyl group through a hydrogen bonding network generated by the catalyst.This activation method allows the reactions to be performed with very low catalyst loading,as low as 0.5 mol%.The scope of substrates is broad and a wide variety of functional groups are well tolerated.Diverse aliphatic aldehydes,aromatic aldehydes,unsaturated aldehydes and aromatic ketones coupled with silyl enol ethers/silyl ketone acetals to generate their correspondingβ-hydroxy carbonyl compounds in moderate to good yields.This discovery represents a significant advancement in the field of organic synthesis,as it provides a new,practical and sustainable solution for carbon-carbon bond formation in water.展开更多
The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry.However,the state of nanobubbles on mineral solid surfaces is still elusive.In this stu...The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry.However,the state of nanobubbles on mineral solid surfaces is still elusive.In this study,molecular dynamics(MD)simulations are employed to examine mineral-like model surfaces with varying degrees of hydrophobicity,modulated by surface charges,to elucidate the adsorption behavior of nanobubbles at the interface.Our findings not only contribute to the fundamental understanding of nanobubbles but also have potential applications in the mining industry.We observed that as the surface charge increases,the contact angle of the nanobubbles increases accordingly with shape transformation from a pancake-like gas film to a cap-like shape,and ultimately forming a stable nanobubble upon an ordered water monolayer.When the solid–water interactions are weak with a small partial charge,the hydrophobic gas(N_(2))molecules accumulate near the solid surfaces.However,we have found,for the first time,that gas molecules assemble a nanobubble on the water monolayer adjacent to the solid surfaces with large partial charges.Such phenomena are attributed to the formation of a hydrophobic water monolayer with a hydrogen bond network structure near the surface.展开更多
Platinum-ruthenium alloys(PtRu)represent state-of-the-art alkaline hydrogen oxidation reaction(HOR)catalysts,yet the atomic-scale origin of their superiority over pure Pt remains incompletely understood.Here,we employ...Platinum-ruthenium alloys(PtRu)represent state-of-the-art alkaline hydrogen oxidation reaction(HOR)catalysts,yet the atomic-scale origin of their superiority over pure Pt remains incompletely understood.Here,we employ density functional theory calculations,ab initio molecular dynamics simulations,and microkinetic modeling on Pt(111)and PtRu(111)surfaces to systematically investigate the key factors,including active sites distribution,species adsorption,and solvent reorganization,that affect the HOR activity and decouple their contributions.The results reveal that while the moderate hydrogen binding energy and improved hydroxyl(OH)species adsorption both contribute to the enhanced activity,the dominant factor is the substantial reduction in solvent reorganization energy on the PtRu(111).This is facilitated by the spatial separation of active sites:Pt atoms preferentially stabilize adsorbed hydrogen,while Ru atoms strongly bind OH and interfacial water molecules.This configuration increases the probability of hydrogen interacting with OH/water and enhances the fraction of"H-up"water molecules,forming a well-organized hydrogen bond network within the electric double layer.The dynamically compatible interfacial water structure and HOR coordination promote H desorption and proton transfer in the Volmer step,thereby accelerating the HOR kinetics.展开更多
Aqueous zinc-ion batteries(AZIBs)are promising due to the advantages of metallic zinc,including the high specific capacity(820 mAh g^(-1)),low redox potential(−0.76 V vs.SHE),inherent safety,low cost,and environmental...Aqueous zinc-ion batteries(AZIBs)are promising due to the advantages of metallic zinc,including the high specific capacity(820 mAh g^(-1)),low redox potential(−0.76 V vs.SHE),inherent safety,low cost,and environmental sustainability.Despite these benefits,AZIBs face challenges such as uneven Zn deposition and excessive hydrogen evolution reaction(HER)at the Zn anode,which reduce the battery's coulombic efficiency and cycling life.This study introduces an ammonium formate(AF)additive into a 2.0 M ZnSO_(4) electrolyte to address these issues.The AF additive promotes the three-dimensional rapid diffusion of Zn^(2+)on the anode surface and induces the preferential Zn(002)plane deposition,thus inhibiting dendrite growth and enhancing cycling stability.It also disrupts the hydrogen bond network of electrolyte,reducing the number of active H2O molecules and suppressing H_(2)O-induced side reactions.Consequently,the Zn||Zn symmetric cell with the AF additive shows stable cycling over 2100 h at 5.0 mA cm^(−2) with an areal capacity of 1.0 mAh cm^(−2),and maintains stability over 9700 cycles at 30 mA cm^(−2).When applied in a Zn||VO_(2) full cell,it achieves capacity retention of 68.9%after 2000 cycles,which demonstrates significant performance improvements in AZIBs.展开更多
We report a new DUV transparent(<200 nm)noncentrosymmetric Na_(1.5)Rb_(0.5)PO_(3)F·H_(2)O compound crystallizing in the Pmn2_(1)space group.This compound exhibits the second largest birefringence in the monofl...We report a new DUV transparent(<200 nm)noncentrosymmetric Na_(1.5)Rb_(0.5)PO_(3)F·H_(2)O compound crystallizing in the Pmn2_(1)space group.This compound exhibits the second largest birefringence in the monofluorophosphate family,Δn_(obv).=0.04 at 546 nm,which is attributed to the nearly uniform alignment of the P-F bonds.The SHG response is observed to be 0.55×KDP at 1064 nm.More interestingly,the precise substitution of NH_(4)^(+)with Na^(+)/Rb^(+)cations in the well-known structure(NH_(4))_(2)PO_(3)F·H_(2)O leads to a stepwise reconstruction of the hydrogen bond networks,which eventually alters the crystal symmetry and the optical properties.展开更多
The production of g-C_(3)N_(4) nanostructures with remarkable charge separation efficiency using a one-step, green, and economic approach is of great challenge. Herein, one-dimensional oxidized porous carbon nitride r...The production of g-C_(3)N_(4) nanostructures with remarkable charge separation efficiency using a one-step, green, and economic approach is of great challenge. Herein, one-dimensional oxidized porous carbon nitride rods are successfully fabricated via re-polymerization of de-aromatized melem-containing oligomers that resulted from the hydrothermal treatment of bulk carbon nitride in pure water and resemble the structures of supramolecular complexes networked with hydrogen bonds. The enlarged surface area and increased porosity have been evidenced by transmission electron microscopy and nitrogen sorption, while the enhanced optical properties and suppressed electron–hole recombination process have been confirmed by diffuse reflectance spectrophotometry and steady-state photoluminescence. Exemplification in photocatalytic rhodamine B degradation reveals significantly improved photoactivity, exhibiting 9.2 and 6.4 times higher kinetic rate constants than that of the bulk carbon nitride under white and blue light irradiation, respectively. The proposed nanocasting strategy via de-aromatization of the heptazine network in bulk g-C_(3)N_(4) overcomes the long-standing serious agglomeration for g-C_(3)N_(4) synthesis and improved photocatalytic activity due to the enhanced light capture capacity and promoted electron–hole separation process.展开更多
The title compound [Ag(CH3CONHC(S)NH2)2](NO3) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. It crystallizes in mo-noclinic, space group P21/c with Mr = 406.20 (C6H1...The title compound [Ag(CH3CONHC(S)NH2)2](NO3) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. It crystallizes in mo-noclinic, space group P21/c with Mr = 406.20 (C6H12Ag N5O5S2), a = 12.0680(6), b = 6.8056(5), c = 18.0173(1) ? b = 111.383(4), V = 1377.9(2) 3, Z = 4, Dc = 1.958 g/cm3 , F(000) = 808, = 1.789 mm-1, R = 0.0361 and wR = 0.1015. Of 4185 reflections ((2)max = 55.00?, 3147 were unique (Rint = 0.0174) and 2820 with I > 2(I) were used to solve the structure. The silver(I) atom adopts V-shape geometry with the AgS bond distance of 2.4271(7) and 2.7229(9) , respectively. Seven atoms of one acetylthiocarbamide ligand are coplanar, while only four atoms of another acetylthio-carbamide ligand are fairly planar. The [Ag(CH3CONHC(S)NH2)2]+ cation and nitrate anion NO3- are connected by hydrogen bonds to form a three dimensional hydrogen bonding network..展开更多
文摘A multi-stimuli-responsive hydrogel,P(VI-co-MAAC-NE),was successfully constructed by covalently integrating the aggregation-induced emission(AIE)moiety(Z)-N-(4-(1-cyano-2-(4-(diethylamino)phenyl)vinyl)-phenyl)methacrylamide(NE)into a dynamic hydrogen-bonding network composed of 1-vinylimidazole(VI)and methacrylic acid(MAAC)groups.The dense hydrogen-bonding network not only provides enhanced mechanical robustness,but also significantly enhances the AIE effect of NE by restricting its molecular motion.Under various external stimuli,the hydrogen bonds within the hydrogel network undergo reversible dissociation and reformation,thus enabling synergistic modulation of the hydrogel’s mechanical properties and luminescence behavior.Specifically,organic solvents disrupt the hydrogen-bonding network and the aggregation of the AIE moiety NE,resulting in macroscopic swelling and fluorescence quenching of the hydrogel.In strongly acidic conditions,protonation of NE molecules suppresses the intramolecular charge transfer(ICT)process,yielding a blue-shifted emission band accompanied by intense blue fluorescence;in highly alkaline environments,deprotonation of carboxyl groups induces hydrogel swelling and disperses NE aggregates,leading to pronounced fluorescence quenching.Moreover,the system exhibits thermally activated shape-memory behavior:heating above the glass transition temperature(T_(g):ca.62℃)softens the hydrogel to allow programmable reshaping,and subsequent hydrogen bond reformation at ambient conditions locks in the resultant geometries without sacrificing the hydrogel’s fluorescence performance.By capitalizing on these multi-stimuli-responsive characteristics and shape-memory behavior,the potential of hydrogel P(VI-co-MAAC-NE)for advanced information encryption and anti-counterfeiting applications is demonstrated.This work not only provides a versatile material platform for sensing and information storage,but also offers new insights into the design of intelligent soft materials integrating AIE features with dynamically regulated supramolecular network structures.
基金supported by the National Natural Science Foundation of China(NSFC 52432002,52372041,and 52302087)China Postdoctoral Science Foundation(Grant No.2023 M740895)+1 种基金Heilongjiang Touyan Team Programthe Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2021003 and HIT.DZJJ.2025002)。
文摘Aqueous Zn-metal batteries(AZMBs)performance is hampered by freezing water at low temperatures,which hampers their multi-scenario application.Hydrogen bonds(HBs)play a pivotal role in water freezing,and proton transport is indispensable for the establishment of HBs.Here,the accelerated proton transport modulates the dynamic hydrogen bonding network of a Zn(BF4)2/EMIMBF4impregnated polyacrylamide/poly(vinyl alcohol)/xanthan gum dual network eutectic gel electrolyte(PPX-ILZSE)for lowtemperature AZMBs.The PPX-ILZSE forms more HBs,shorter HBs lifetimes,higher tetrahedral entropy,and faster desolvation processes,as demonstrated by experimental and theoretical calculations.This enhanced dynamic proton transport promotes rapid cycling of HBs formation-failure,and for polyaniline cathode(PANI)abundant redox sites of proton,confers excellent low temperature electrochemical performance to the Zn//PANI full cell.Specific capacities for 1000 and 5000 cycles at 1 and 5 A g^(-1)were149.8 and 128.4 m A h g^(-1)at room temperature,respectively.Furthermore,specific capacities of 131.1 mA hg^(-1)(92.4%capacity retention)and 0.0066%capacity decay per lap were achieved for 3000and 3500 laps at-30 and 40℃,respectively,at 0.5 A g^(-1).Furthermore,in-situ protective layer of ZnOHF nano-arrays on the Zn anode surface to eliminate dendrite growth and accelerate Zn-ions adsorption and charge transfer.
基金supported by the National Natural Science Foundation of China(30371009, 30471218) Science Foundation of Fujian Department of Education (JA03059)
文摘In this paper, the hydrogen bonding network models of konjac glucomannan （KGM） are predicted in the approach of molecular dynamics （MD）. These models have been proved by experiments whose results are consistent with those from simulation. The results show that the hydrogen bonding network structures of KGM are stable and the key linking points of hydrogen bonding network are at the O（6） and O（2） positions on KGM ring. Moreover, acety has significant influence on hydrogen bonding network and hydrogen bonding network structures are more stable after deacetylation.
基金Supported by the Youth Foundation of Jiangxi Provincial Office of Education (GJJ09605)the Science Foundation of Jiangxi Provincial Office of Education (GJJ09637)
文摘Hydrothermal reaction of MgCl2 and ethyl tetrazolate-5-carboxylate at 160 ℃unexpectedly yielded compound {（H3O）[Mg（H2O）6]Cl3} （1）. The result of X-ray diffraction analysis indicates that 1 crystallizes in the monoclinic system, space group C2/c with a = 9.2896（3）, b = 9.5570（4）, c = 13.3169（5） A, β = 90.1221（12）°, V= 1182.28（8） A3, Z = 4, Mr = 257.78, Dc = 1.448 g/cm3, μ = 0.824 mm^-1, F（000） = 536, R = 0.0265 and wR - 0.0706. 1 is composed of one hexa-aqua-magnesium（Ⅱ） ion, one hydroxonium ion, and three chlorine anions. These three components weave a perfect three-dimensional （3D） （4,4,6,12）-connected hydrogen bonding network within 1.
基金financial support from the Natural Science Foundations of China(51173082)from Jiangsu Province and PAPD(13KJB150028,BM2012010,BK20141425 and YX03001)the Program for Postgraduates Research Innovation in University of Jiangsu Province(CXZZ12-0456).
文摘A series of inorganic acids were introduced into the self-assembly with the bent 2,5-bis(4-pyridyl)-1,3,4-oxadiazole(4-bpo),yielding seven anion-assisted supramolecular salts,i.e.[(4-H_(2)bpo^(2+))·(NO_(3)^(−))_(2)]·2H_(2)O(1),(4-H_(2)bpo^(2+))·(HPO_(4)^(2−))(2),[(4-H_(2)bpo^(2+))_(2)·(4-Hbpo^(+))·(I_(3)^(−))_(3)·(I^(−))_(2)]·2H_(2)O(3),[(4-Hbpo^(+))_(2)·(PF_(6)^(−))_(2)]·H_(2)O(4),[(4-H_(2)bpo^(2+))·(BF_(4)^(−))_(2)]·H_(2)O(5),[(4-Hbpo^(+))·(BF_(4)^(−))](6)and(4-H_(2)bph^(2+))·(SO_(4)^(2−))(7).Structural analyses indicate that different inorganic anions(e.g.spherical,linear,trigonal planar,tetrahedral and octahedral)can induce the formation of diverse supramolecular architectures,influencing the crystallization ratio,the protonated number and the final structure.The anions are hydrogen bonded to the angular dipyridine,which offers a sufficient driving force for the directed assembly of supramolecular hydrogen-bonding frameworks.Thereto,various hydrogen-bonding motifs are observed in all these cases(1–7)and the nitrogen atoms of pyridines are protonated apart from salt 6.Among them,salts 1,3,4 and 5 crystallize with water molecules but the others do not.Interestingly,appealing substructures have been generated by anions and water molecules in 1,3 and 5 but not in 4.HPO_(4)^(2−)dimers form in 2 despite there being no assistance from solvent water.BF_(4)^(−)anions facilitate the formation of the helical chain in 6.Unexpectedly,the oxadiazole ring opened via the in situ hydrolysis under hydrothermal conditions during crystallization with H_(2)SO_(4),producing salt 7.
基金supported by Chongqing Technology Innovation and Application Development Special Key Project,CSTB2023TIAD-KPX0010 and Chongqing Technology Innovation and Application Development Special Major Project,CSTB2023TIAD-STX0033,and the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsNatural Science Foundation of Chongqing,China(Nos.CSTC2021jcyj-msxmX1035,CSTB2022NSCQ-MSX0246,CSTB2022NSCQ-MSX0242,CSTB2022NSCQ-MSX1244,CSTB2022NSCQ-MSX0441,CSTB2022NSCQ-MSX1356,CSTB2022NSCQ-MSX1572,CSTB2022NSCQ-MSX1583,CSTB2022NSCQ-MSX0487,CSTB2022TFII-OFX0034)Fundação para a Ciência e Tecnologia(FCT)for financial support under the framework of Strategic Funding UIDB/04650/2020,UID/FIS/04650/2020,UID/EEA/04436/2020,and under project,10.54499/2022.03931.
文摘Expanded polytetrafluoroethylene(e-PTFE)reinforced perfluorosulfonic acid(PFSA)is the predominant proton exchange membrane(PEM)for hydrogen fuel cells.However,the difference in interfacial properties between PFSA and e-PTFE significantly decreases the proton conduction efficiency and durability of the PEM.In this study,the polyphenolamine treatment method(TA)is employed to effectively enhance the hydrophilicity and interfacial compatibility of e-PTFE,as well as to functionalize the surface of the free radical scavenger ZrO_(2) filler.The surface of the modified e-PTFE and ZrO_(2) is rich in polar phenolic hydroxyl groups and amino groups,which effectively enhance the three-dimensional interface compatibility of the e-PTFE/PFSA reinforced composite membrane(RCM),and improve the proton conductivity by establishing a three-dimensionally-reinforced hydrogen bonding network.The proton conductivity of the RCM is 0.203 S cm^(-1) at 80℃,and the tensile strength is 50.7 MPa.The peak power density of the hydrogen fuel cell based on the composite membrane is 1.46 W cm^(-2) at 80℃ and 50%RH.Moreover,the durability of the composite membrane is considerably improved by the redox properties of the surface functional groups of e-PTFE and the valence-changing properties of ZrO_(2).Following a 72-hour Fenton reaction,the mass loss of the TA@ZrO_(2)/e-PTFE RCM was found to be only 13.5%.The accelerated durability test indicates that the TA@ZrO_(2)/e-PTFE RCM can still provide a current density of 1.3 A cm^(-2) after 5500 dry/wet cycles at 0.55 V.
基金supported by the National Natural Science Foundation of China(32071715)the National Science Foundation of Tianjin City(22JCZDJC00560)。
文摘As an earth-abundant and natural biopolymer,cellulose has received significant attention in aqueous zinc-ion batteries(AZIBs)due to its inherent sustainability and non-toxicity,aligning perfectly with the core advantages of AZIBs.Nevertheless,the practical implementation of cellulose-based materials is limited by their intrinsically low ionic conductivity.Herein,we introduce a novel zincophilic artificial protective layer by strategically hybridizing hydroxypropyl cellulose(HPC)with zinc trifluoromethanesulfonate on a zinc metal anode(HZ@Zn).Characterization and calculations demonstrate that the multihydroxyl architecture of HPC constructs hydrogen bond networks,whereas the Zn^(2+)-coordinated HPC domains function as preferential nucleation sites for zinc deposition.These interactions collectively enhance ion transport and accelerate desolvation kinetics.Additionally,the hybrid layer's mechanical flexibility and interfacial adhesion ensure the integrity of the artificial protective layer during long cycling.Thanks to this synergistic effect,HZ@Zn shows exceptional electrochemical performance,including a low desolvation activation energy of 14.38 kJ mol^(-1)and ultra-long cycling stability.Symmetric cells demonstrate exceptional longevity,exceeding 9,500 h at 0.5 mA cm^(-2)/0.25 mAh cm^(-2),whereas HZ@Zn‖PANI full cells maintain 89.8%capacity retention after 4000 cycles at 5 A g^(-1).This study establishes biopolymers as versatile platforms for effectively stabilizing the zinc metal anode.
基金The authors gratefully acknowledge supports from the National Natural Science Foundation of China(Grant Nos.21975209,21673197,51706191,and 21621091)the National Key R&D Program of China(Grant No.2018YFA0209500)+3 种基金the 111 Project(Grant No.B16029)the Fundamental Research Funds for the Central Universities(Grant No.20720190037)the Natural Science Foundation of Fujian Province of China(Grant No.2018J06003)CAS Key Laboratory of Bio-inspired Materials and Interfacial Science,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences.
文摘The development of membranes featuring carbon nanotubes(CNTs)have provided possibilities of next-generation solar desalination technologies.For solar desalination,the microstructures and interactions between the filter membrane and seawater play a crucial role in desalination performance.Understanding the mechanisms of water evaporation and ion rejection in confined pores or channels is necessary to optimize the desalting process.Here,using non-equilibrium molecular dynamics simulations,we found that continuous water-water hydrogen bonding network across the rims of CNTs is the key factor in facilitating water transport through CNTs.With the continuous hydrogen bonding network,the water flux is two times of that without the continuous hydrogen bonding network.In CNT arrays,each CNT transports water molecules and rejects salt ions independently.Based on these observations,using CNT arrays consisted with densely packed thin CNTs is the most advisable strategy for evaporation desalination,possessing high transport flux as well as maintaining high salt rejection.
基金financially supported by the National Natural Science Foundation of China (No.52372188)the 111 Project (No.D17007)2023 Introduction of studying abroad talent program。
文摘Aqueous zinc-ion batteries(AZIBs) have advantages including low economic cost and high safety.Nevertheless,the serious hydrogen evolution reactions(HER) and rampant growth of Zn dendrite hinder their further development.Herein,potassium acetate(KAc) additive with cation/anion synergy effect is added into the ZnSO_(4) electrolyte to effectively promote the oriented uniform Zn deposition and suppress side reactions.According to density functional theory calculation and experimental results,CH_(3)COO^(-)(Ac^(-))anions are capable of forming stronger hydrogen bonds with H_(2)O molecules,leading to an expanded electrochemical stability window,reduced the reactivity of H_(2)O,and hence suppressing HER.Meanwhile,Ac-anions can also preferentially adsorb onto the Zn anode,promoting dense deposition towards the(100) crystal plane.Besides,dissociated K^(+) ions serve as electrostatic shielding cations,which significantly promote uniform Zn deposition and prevent dendrite formation.Thus,the Zn||Zn symmetric cell demonstrates an impressive cycle lifespan of 3000 h at 1.0 m A/cm^(2).Furthermore,the Zn||MnO_(2) full battery exhibits superior stability with a capacity retention of 86.95 % at 2.0 A/g after 4000 cycles.Therefore,the cation/anion synergy effect in KAc additive offers a viable solution to address HER and hinder dendrite growth at the interface of Zn anodes.
基金supported by the National Natural Science Foundation of China(52002297)National Key R&D Program of China(2022VFB2404800)+1 种基金Wuhan Yellow Crane Talents Program,China Postdoctoral Science Foundation(No.2024M752495)the Postdoctoral Fellowship Program of CPSF(No.GZB20230552).
文摘Aqueous alkali metal-ion batteries(AAMIBs)have been recognized as emerging electrochemical energy storage technologies for grid-scale applications owning to their intrinsic safety,cost-effectiveness,and environmental sustainability.However,the practical application of AAMIBs is still severely constrained by the tendency of aqueous electrolytes to freeze at low temperatures and decompose at high temperatures,limiting their operational temperature range.Considering the urgent need for energy systems with higher adaptability and resilience at various application scenarios,designing novel electrolytes via structure modulation has increasingly emerged as a feasible and economical strategy for the performance optimization of wide-temperature AAMIBs.In this review,the latest advancement of wide-temperature electrolytes for AAMIBs is systematically and comprehensively summarized.Specifically,the key challenges,failure mechanisms,correlations between hydrogen bond behaviors and physicochemical properties,and thermodynamic and kinetic interpretations in aqueous electrolytes are discussed firstly.Additionally,we offer forward-looking insights and innovative design principles for developing aqueous electrolytes capable of operating across a broad temperature range.This review is expected to provide some guidance and reference for the rational design and regulation of widetemperature electrolytes for AAMIBs and promote their future development.
基金Supported by the National Natural Science Foundation of China(31271837 and 31071518)Specialized Research Fund for the Doctoral Program of Higher Education jointly funded by Ministry of Education(20113515110010)+2 种基金Special Research Funds from Ministry of Science and Technology(2012GA7200022)Major projects of industries,universities and research in Fujian Province(2013N5003)Natural Science Foundation of Fujian Province(2011J0101)
文摘Based on the knot theory and researching of network structures of glucomannan molecules, the polysaccharides were analyzed. The link prediction analysis is to further reveal the interactions between polysaccharides, to elaborate QSAR of polysaccharides, and to analyze the network conformation relationships among polysaccharides. We made a classification for glucomannan molecules based on the related domestic and international theories, and investigated their network structures and application prospects. The knot theory and the link predictions not only simplify the glucomannan microscopic descriptions but also play a guiding role in predicting and regulating the structures.
基金financially supported by the National Natural Science Foundation of China (Nos.51973118, 22175121,52003160 and 22001175)Key-Area Research and Development Program of Guangdong Province (Nos.2019B010941001 and2019B010929002)+7 种基金the Natural Science Foundation of Guangdong Province (No.2020A1515010644)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2019ZT08C642)Shenzhen Science and Technology Program (Nos.JCYJ20220818095810022, JSGGZD20220822095201003 and JCYJ20210324095412035)the start-up fund of Shenzhen University (No.000002110820)the Guangdong Natural Science Foundation (Nos.2022A1515011781 and2021A1515110086)Science and Technology Innovation Commission of Shenzhen,China (Nos.RCBS20200714114910141 and JCYJ20210324132816039)the Start-up Grant at Harbin Institute of Technology (Shenzhen),China (Nos.HA45001108 and HA11409049)Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive Application (No.ZDSYS20220527171407017)。
文摘The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of society.Since the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine solution.This study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.
基金supported by the China Postdoctoral Science Foundation(No.2014M551053)Natural Science Foundation of Hebei Province(No.B2015203124)Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University
文摘Two crystals of receptor 1, C（42）H（52）N（10）O4S2（anthracene-9,10-dicarbaldehyde bis-（phenyl-semithiocarbazone）） and-1-H2PO4, C（68）H（114）N（10）O（10）P2S2 were obtained at room temperature successfully, and their structures were characterized by X-ray crystallography diffraction. X-ray diffraction reveals that, receptor 1 crystallizes in monoclinic, space group P21/c, with a = 9.487（3）,b = 20.674（6）, c = 11.821（4）A, β = 113.416（8）o, Mr = 825.06, V = 2127.5（12） A^3, Z = 2, Dc = 1.288g/cm^3, μ = 0.18 mm^-1, F（000） = 876, MoK α radiation（λ = 0.71073 A）, the final R = 0.0472 and wR = 0.0930. A total of 3758 unique reflections were collected, of which 3313 with I 〉 2σ（I） were observed. Compound 1-H2PO4^-crystallizes in triclinic, space group P21/n, with a = 8.767（1）, b =13.6190（15）, c = 16.615（2） ？, α = 98.727（14）, β = 103.061（14）, γ = 91.382（16）°, Mr = 1357.75, V =1906.6（4） A^3, Z = 1, Dc = 1.183 g/cm^3, μ = 0.17 mm-（-1）, F（000） = 734, MoK α radiation（λ = 0.71073？）, the final R = 0.0769 and wR = 0.1884. A total of 6699 unique reflections were collected, of which 2989 with I 〉 2σ（I） were observed. As it was observed in the crystal structure of 1-H2PO4^-, 1bound H2PO4^-at a 1：2 ratio by intermolecular interaction of N-H···O hydrogen bond obviously.Another interesting feature was that H2PO4--groups assembled chains themselves via intramolecular hydrogen bond O-H···O and connected the 1 molecules together through the interaction of H-bonds,which improved the planarity of 1 and increased the stability of the entire structure.
基金financial support from the Start-up Grant of Nanjing Tech University(Nos.38274017103,38037037)financial support from Distinguished University Professor grant(Nanyang Technological University)+1 种基金the Agency for Science,Technology and Research(A∗STAR)under its MTC Individual Research Grants(No.M21K2c0114)RIE2025 MTC Programmatic Fund(No.M22K9b0049).
文摘A“water”accelerated metal-free catalytic system has been discovered for the Mukaiyama-aldol reaction.The system involves the use of B(C_(6)F_(5))_(3) as a catalyst,which is water-tolerant and able to activate the carbonyl group through a hydrogen bonding network generated by the catalyst.This activation method allows the reactions to be performed with very low catalyst loading,as low as 0.5 mol%.The scope of substrates is broad and a wide variety of functional groups are well tolerated.Diverse aliphatic aldehydes,aromatic aldehydes,unsaturated aldehydes and aromatic ketones coupled with silyl enol ethers/silyl ketone acetals to generate their correspondingβ-hydroxy carbonyl compounds in moderate to good yields.This discovery represents a significant advancement in the field of organic synthesis,as it provides a new,practical and sustainable solution for carbon-carbon bond formation in water.
基金supported by the National Natural Science Foundation of China(Grant Nos.12022508,12074394,and 22125604)Shanghai Supercomputer Center of ChinaShanghai Snowlake Technology Co.Ltd.
文摘The stable nanobubbles adhered to mineral surfaces may facilitate their efficient separation via flotation in the mining industry.However,the state of nanobubbles on mineral solid surfaces is still elusive.In this study,molecular dynamics(MD)simulations are employed to examine mineral-like model surfaces with varying degrees of hydrophobicity,modulated by surface charges,to elucidate the adsorption behavior of nanobubbles at the interface.Our findings not only contribute to the fundamental understanding of nanobubbles but also have potential applications in the mining industry.We observed that as the surface charge increases,the contact angle of the nanobubbles increases accordingly with shape transformation from a pancake-like gas film to a cap-like shape,and ultimately forming a stable nanobubble upon an ordered water monolayer.When the solid–water interactions are weak with a small partial charge,the hydrophobic gas(N_(2))molecules accumulate near the solid surfaces.However,we have found,for the first time,that gas molecules assemble a nanobubble on the water monolayer adjacent to the solid surfaces with large partial charges.Such phenomena are attributed to the formation of a hydrophobic water monolayer with a hydrogen bond network structure near the surface.
文摘Platinum-ruthenium alloys(PtRu)represent state-of-the-art alkaline hydrogen oxidation reaction(HOR)catalysts,yet the atomic-scale origin of their superiority over pure Pt remains incompletely understood.Here,we employ density functional theory calculations,ab initio molecular dynamics simulations,and microkinetic modeling on Pt(111)and PtRu(111)surfaces to systematically investigate the key factors,including active sites distribution,species adsorption,and solvent reorganization,that affect the HOR activity and decouple their contributions.The results reveal that while the moderate hydrogen binding energy and improved hydroxyl(OH)species adsorption both contribute to the enhanced activity,the dominant factor is the substantial reduction in solvent reorganization energy on the PtRu(111).This is facilitated by the spatial separation of active sites:Pt atoms preferentially stabilize adsorbed hydrogen,while Ru atoms strongly bind OH and interfacial water molecules.This configuration increases the probability of hydrogen interacting with OH/water and enhances the fraction of"H-up"water molecules,forming a well-organized hydrogen bond network within the electric double layer.The dynamically compatible interfacial water structure and HOR coordination promote H desorption and proton transfer in the Volmer step,thereby accelerating the HOR kinetics.
基金supported by the Natural Science Foundation of Guangxi(2022JJD120011)the National Natural Science Foundation of China(22479031,22162004).
文摘Aqueous zinc-ion batteries(AZIBs)are promising due to the advantages of metallic zinc,including the high specific capacity(820 mAh g^(-1)),low redox potential(−0.76 V vs.SHE),inherent safety,low cost,and environmental sustainability.Despite these benefits,AZIBs face challenges such as uneven Zn deposition and excessive hydrogen evolution reaction(HER)at the Zn anode,which reduce the battery's coulombic efficiency and cycling life.This study introduces an ammonium formate(AF)additive into a 2.0 M ZnSO_(4) electrolyte to address these issues.The AF additive promotes the three-dimensional rapid diffusion of Zn^(2+)on the anode surface and induces the preferential Zn(002)plane deposition,thus inhibiting dendrite growth and enhancing cycling stability.It also disrupts the hydrogen bond network of electrolyte,reducing the number of active H2O molecules and suppressing H_(2)O-induced side reactions.Consequently,the Zn||Zn symmetric cell with the AF additive shows stable cycling over 2100 h at 5.0 mA cm^(−2) with an areal capacity of 1.0 mAh cm^(−2),and maintains stability over 9700 cycles at 30 mA cm^(−2).When applied in a Zn||VO_(2) full cell,it achieves capacity retention of 68.9%after 2000 cycles,which demonstrates significant performance improvements in AZIBs.
基金supported by the National Natural Science Foundation of China(21975032)Beijing Natural Science Foundation(2202022).
文摘We report a new DUV transparent(<200 nm)noncentrosymmetric Na_(1.5)Rb_(0.5)PO_(3)F·H_(2)O compound crystallizing in the Pmn2_(1)space group.This compound exhibits the second largest birefringence in the monofluorophosphate family,Δn_(obv).=0.04 at 546 nm,which is attributed to the nearly uniform alignment of the P-F bonds.The SHG response is observed to be 0.55×KDP at 1064 nm.More interestingly,the precise substitution of NH_(4)^(+)with Na^(+)/Rb^(+)cations in the well-known structure(NH_(4))_(2)PO_(3)F·H_(2)O leads to a stepwise reconstruction of the hydrogen bond networks,which eventually alters the crystal symmetry and the optical properties.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20210608)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(21KJA150003)。
文摘The production of g-C_(3)N_(4) nanostructures with remarkable charge separation efficiency using a one-step, green, and economic approach is of great challenge. Herein, one-dimensional oxidized porous carbon nitride rods are successfully fabricated via re-polymerization of de-aromatized melem-containing oligomers that resulted from the hydrothermal treatment of bulk carbon nitride in pure water and resemble the structures of supramolecular complexes networked with hydrogen bonds. The enlarged surface area and increased porosity have been evidenced by transmission electron microscopy and nitrogen sorption, while the enhanced optical properties and suppressed electron–hole recombination process have been confirmed by diffuse reflectance spectrophotometry and steady-state photoluminescence. Exemplification in photocatalytic rhodamine B degradation reveals significantly improved photoactivity, exhibiting 9.2 and 6.4 times higher kinetic rate constants than that of the bulk carbon nitride under white and blue light irradiation, respectively. The proposed nanocasting strategy via de-aromatization of the heptazine network in bulk g-C_(3)N_(4) overcomes the long-standing serious agglomeration for g-C_(3)N_(4) synthesis and improved photocatalytic activity due to the enhanced light capture capacity and promoted electron–hole separation process.
基金This work was supported by the Natural Science Foundation of Shandong province (No.Y2002B06) and Science Research Foundation of Qingdao University of Science and Technology (No. 03Z08)
文摘The title compound [Ag(CH3CONHC(S)NH2)2](NO3) has been prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. It crystallizes in mo-noclinic, space group P21/c with Mr = 406.20 (C6H12Ag N5O5S2), a = 12.0680(6), b = 6.8056(5), c = 18.0173(1) ? b = 111.383(4), V = 1377.9(2) 3, Z = 4, Dc = 1.958 g/cm3 , F(000) = 808, = 1.789 mm-1, R = 0.0361 and wR = 0.1015. Of 4185 reflections ((2)max = 55.00?, 3147 were unique (Rint = 0.0174) and 2820 with I > 2(I) were used to solve the structure. The silver(I) atom adopts V-shape geometry with the AgS bond distance of 2.4271(7) and 2.7229(9) , respectively. Seven atoms of one acetylthiocarbamide ligand are coplanar, while only four atoms of another acetylthio-carbamide ligand are fairly planar. The [Ag(CH3CONHC(S)NH2)2]+ cation and nitrate anion NO3- are connected by hydrogen bonds to form a three dimensional hydrogen bonding network..
