Synergism of preintercalated manganese ions and lattice water in vanadium oxide cathodes for high-capacity and long-life Zn-ion batteries

Aqueous Zn-ion batteries(AZIBs)are recognized as a promising energy storage system with intrinsic safety and low cost,but its applications still rely on the design of high-capacity and stable-cycling cathode materials.In this work,we present an intercalation mechanism-based cathode materials for AZIB,i.e.the vanadium oxide with pre-intercalated manganese ions and lattice water(noted as MVOH).The synergistic effect between Mn^(2+)and lattice H_(2)O not only expands the interlayer spacing,but also significantly enhances the structural stability.Systematic in-situ and ex-situ characterizations clarify the Zn^(2+)/H^(+)co–(de)intercalation mechanism of MVOH in aqueous electrolyte.The demonstrated remarkable structure stability,excellent kinetic behaviors and ion-storage mechanism together enable the MVOH to demonstrate satisfactory specific capacity of 450 mA h g^(−1)at 0.2 A g^(−1),excellent rate performance of 288.8 mA h g^(−1)at 10 A g^(−1)and long cycle life over 20,000 cycles at 5 A g^(−1).This work provides a practical cathode material,and contributes to the understanding of the ion-intercalation mechanism and structural evolution of the vanadium-based cathode for AZIBs.

Facile preparation of Ag_(2)S/KTa_(0.5)Nb_(0.5)O_(3) heterojunction for enhanced performance in catalytic nitrogen fixation via photocatalysis and piezo-photocatalysis

In this work, a novel heterojunction composite Ag_(2)S/KTa_(x)Nb_(1-x)O_(3)was designed and synthesized through a combination of hydrothermal and precipitation procedures. The Ta/Nb ratio of the KTa_(x)Nb_(1-x)O_(3)and the Ag_(2)S content were optimized. The best 0.5% Ag_(2)S/KTa_(0.5)Nb_(0.5)O_(3)(KTN) sample presents an enhanced photocatalytic performance in ammonia synthesis than KTN and Ag_(2)S. Under simulated sunlight, the NH_(3)generation rate of 0.5% Ag_(2)S/KTN reaches 2.0 times that of pure KTN. Under visible light, the reaction rate ratio of the two catalysts is 6.0.XRD, XPS, and TEM analysis revealed that Ag2S was intimately decorated on the KTN nanocubes surface, which promoted the electron transfer between the two semiconductors. The band structure investigation indicated that the Ag_(2)S/KTN heterojunction established a type-Ⅱ band alignment with intimate contact, thus realizing the effective transfer and separation of photogenerated carriers. The change in charge separation was considered as the main reason for the enhanced photocatalytic performance. Interestingly, the Ag_(2)S/KTN composite exhibited higher NH3generation performance under the combined action of ultrasonic vibration and simulated sunlight. The enhanced piezo-photocatalytic performance can be ascribed that the piezoelectric effect of KTN improved the bulk separation of charge carriers in KTN. This study not only provides a potential catalyst for photocatalytic nitrogen fixation but also shows new ideas for the design of highly efficient catalysts via semiconductor modification and external field coupling.

High piezo/photocatalytic efficiency of Ag/Bi_(5)O_(7)I nanocomposite using mechanical and solar energy for N2 fixation and methyl orange degradation

In this work,Ag/Bi_(5)O_(7)I nanocomposite was prepared and firstly applied in piezo/photocatalytic reduction of N2 to NH3 and methyl orange(MO)degradation.Bi_(5)O_(7)I was synthesized via a hydrothermal-calcination method and shows nanorods morphology.Ag nanoparticles(NPs)were photo deposited on the Bi_(5)O_(7)I nanorods as electron trappers to improve the spatial separation of charge carriers,which was confirmed via XPS,TEM,and electronic chemical analyses.The catalytic test indicates that Bi_(5)O_(7)I presents the piezoelectric-like behavior,while the loading of Ag NPs can strengthen the character.Under ultrasonic vibration,the optimal Ag/Bi_(5)O_(7)I presents high efficiency in MO degradation.The degradation rate is determined to be 0.033 min
1,which is 4.7 folds faster than that of Bi_(5)O_(7)I.The Ag/Bi_(5)O_(7)I also presents a high performance in piezocatalytic N2 fixation.The piezocatalytic NH3 generation rate reaches 65.4 μmol L^(-1)g^(-1)h^(-1)with water as a hole scavenger.The addition of methanol can hasten the piezoelectric catalytic reaction.Interestingly,when ultrasonic vibration and light irradiation simultaneously act on the Ag/Bi_(5)O_(7)I catalyst,higher performance in NH3 generation and MO degradation is observed.However,due to the weak adhesion of Ag NPs,some Ag NPs would fall off from the Bi_(5)O_(7)I surface under long-term ultrasonic vibration,which would greatly reduce the piezoelectric catalytic performance.This result indicates that a strong binding force is required when preparing the piezoelectric composite catalyst.The current work provides new insights for the development of highly efficient catalysts that can use multiple energies.

Precise regulation of pyrrole-type single-atom Mn-N4 sites for superior pH-universal oxygen reduction

The study of atomically dispersed metal-nitrogen electrocatalysts is still limited in terms of understanding their catalytic mechanism because of the inability to precisely regulate the coordination number and type of N in combination with the metal elements.Inspired by the high catalytic activity and selectivity of natural enzymes,herein,we have designed and fabricated ultrathin carbon nanosheet-supported Mn single-atom catalysts(SACs)with a precise pyrrole-type Mn-N4(PT-MnN4)configuration using a bio-mimicking strategy.The PT-MnN4 SACs display outstanding oxygen reduction reaction(ORR)activity,with a half-wave potential(E_(1/2))of 0.88 V(vs.revisible hydrogen electrode[RHE])and extremely high stability in alkaline media.Moreover,superior ORR activities are also obtained,E_(1/2) of 0.73 V and 0.63 V in acid and neutral electrolytes,respectively,indicating the efficient pH-universal ORR performances.The assembled zinc-air battery using the PT-MnN4 SACs as air cathodes exhibits a high peak power density(175 mW cm^(−2))and long-term stability up to 150 h,implying its promising application in metal-air batteries.This study has paved the way toward the rational design and precise regulation of single-atom electrocatalysts.

New types of hybrid electrolytes for supercapacitors

Supercapacitors(SCs)are emerging as efficient energy storage devices but still suffering from limited energy density compared with batteries.Electrolytes have been regarded as the key to determine the energy storage performance of SCs.However,none of the conventional electrolytes can fully meet the increasing requirements of SCs in terms of high ion conductivity,excellent stability,wide voltage window and operating temperature range,as well as environmentally friend concerns.To this end,hybrid electrolytes have sprung up in recent years,which are believed to be the candidate to solve these shortcomings.Herein,the state-of-the-art types of hybrid electrolytes for SCs,including the combination of aqueous and organic,aqueous and gel polymer,ionic liquids(ILs)and organic,and ILs and gel polymer hybrid electrolytes,are reviewed.The effects of different hybrid systems on the performance of SCs and the underlying mechanisms are among the focal points of the review,and prospects and possible directions are discussed as well to provide further insight into the future development of this field.

Structural Modulation of Two Luminescent Bismuth-organic Frameworks by the Mixed-ligand Synthetic Strategy

Hydrothermal reactions of Bi2O3 with pyridine-2,6-dicarboxylic acid （2,6-H2pdc） and trimesic acid （H3btc）/pyromellitic acid （H4pyr） lead to two bismuth-organic frameworks, namely, [Bi（2,6-pdc）（H2btc）（H2O）2]n （1） and [Bi2（2,6-pdc）2（H2pyr）（H2O）2]n （2）. Compound 1 crystallizes in the space group P21/c. The dimeric {Bi2} units are linked by 2,6-pdc2？ ligands to form 1D chains; Compound 2 exhibits a 2D layered structure with 44 network topology by using dimeric {Bi2} as secondary building units （SBUs）. The chains and layers in 1 and 2 are further arranged into 3D supramolecular structures via hydrogen bonding interactions. The compounds emit blue luminescence. Furthermore, the PXRD, TGA, UV-visible and IR spectra were also studied. Compounds 1, 2 represent good examples of using mixed-ligand approach to construct diversity of luminescent bismuth-organic frameworks.

Photocatalytic Site-Selective Cascade Radical Addition of Biaryl Ynones for the Construction of Spiro-and Fused Carbon Rings

Functionalized free radical addition/cyclization reactions represent an efficient way for introducing new functionality or coupling fragments to molecules.Ynones are good regional selectivity radical acceptors in organic synthesis,and many of bio-relevant cyclic compounds could be easily obtained by direct radical cyclization reaction.Here,we report a photocatalytic cascade radical addition of biaryl ynones,for the divergent synthesis of privileged carbon cycles.Additionally,further transformation of the multi-functional group product into a variety of other derivatives demonstrates the synthetic value of this developed method.

Enhanced photocatalytic nitrogen fixation performance via in situ constructing BiO_(2-x)/NaNbO_(3) heterojunction

The fabrication of heterojunction catalysts is an effective strategy to enhance charge separation efficiency,thereby boosting the performance of photocatalysts.In this study,BiO_(2-x)nanosheets were synthesized through a hydrothermal process and loaded onto NaNbO_(3) microcube to construct a series of BiO_(2-x)/NaNbO_(3) heterojunctions for photocatalytic N_(2) fixation.Results indicated that 2.5%BiO_(2-x)/NaNbO_(3) had the highest photocatalytic performance.The NH_(3) production rate under simulated solar light reached 406.4μmol·L^(-1)·g^(-1)·h^(-1),which reaches 2.6 and 3.8 times that of NaNbO_(3) and BiO_(2-x),respectively.BiO_(2-x)nanosheets primarily act as electron trappers to enhance the separation efficiency of charge carriers.The strong interaction between BiO_(2-x)and NaNbO_(3) facilitates the electron migration between them.Meanwhile,the abundant oxygen vacancies in BiO_(2-x)nanosheets may facilitate the adsorption and activation of N_(2),which may be another possible reason of the high photocatalytic activity of the BiO_(2-x)/NaNbO_(3).This study may offer new insights for the development of semiconductor materials in photocatalytic nitrogen fixation.

Strain‑Induced Surface Interface Dual Polarization Constructs PML‑Cu/Bi_(12)O_(17)Br_(2) High‑Density Active Sites for CO_(2) Photoreduction

The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.Herein,strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer(PML-Cu)and Bi_(12)O_(17)Br_(2)(BOB),which triggers the surface interface dual polarization of PML-Cu/BOB(PBOB).In this multi-step polarization,the built-in electric field formed between the interfaces induces the electron transfer from con-duction band(CB)of BOB to CB of PML-Cu and suppresses its reverse migration.Moreover,the surface polarization of PML-Cu further promotes the electron converge in Cu atoms.The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB,significantly promoting the adsorption and activation of CO_(2) and CO desorption.The conversion rate of CO_(2) photoreduction to CO for PBOB can reach 584.3μmol g-1,which is 7.83 times higher than BOB and 20.01 times than PML-Cu.This work offers valuable insights into multi-step polarization regulation and active site design for catalysts.

Amorphous 3D pomegranate-like NiCoFe nanoassemblies derived by bi-component cyanogel reduction for outstanding oxygen evolution reaction

As a representative type of self-supported templates, cyano-bridged cyanogels provide ideal plateaus for synthesis of three-dimensional(3 D) nanostructures. Herein, 3 D pomegranate-like Fe-doped NiCo nanoassemblies(3 D PG-NiCoFe NAs) were synthesized via facile one-step bi-component cyanogel reduction with NaBH_4 as the reducing agent. Specifically, the influence of the incorporated Fe amount was carefully investigated by finely adjusting the feeding molar ratios of the Ni/Co/Fe atoms in the precursors.By virtue of the unique structure and enriched oxygen vacancies originated from well-modulated electronic structures, the 3 D PG-NiCoFe-211 NAs exhibited outstanding electrocatalytic performances for oxygen evolution reaction(OER) in alkaline solution, outperforming commercial RuO_2 catalyst. The current incorporation of foreign metal atom into host material provides some valuable insights into design and synthesis of metal-based nanocatalysts for constructing practical water splitting devices.

Cobalt-nanoparticle catalysts derived from zeolitic imidazolate framework@MXene composites for efficient oxidative self-coupling of benzylamines

In this study,we synthesize a catalyst comprising cobalt nanoparticles supported on MXene by pyrolyzing a composite in a N2 environment.Specifically,the composite comprises a bimetallic Zn/Co zeolitic imidazole framework grown in situ on the outer surface of MXene.The catalytic efficiency of the catalyst is tested for the self-coupling of 4-methoxybenzylamine to produce value-added imine,where atmospheric oxygen(1 atm)is used as the oxidant.Based on the results,the catalyst displayed impressive catalytic activity,achieving 95.4%yield of the desired imine at 383 K for 8 h.Furthermore,the catalyst showed recyclability and tolerance toward benzylamine substrates with various functional groups.The outstanding performance of the catalyst is primarily attributed to the synergetic catalytic effect between the cobalt nanoparticles and MXene support,while also benefiting from the three-dimensional porous structure.Additionally,a preliminary investigation of potential reaction mechanisms is conducted.

Deciphering dynamic surface of PtRu alloy nanocatalysts to revisit their synergistic effects during the electrooxidation

Correlating dynamic structural transformation of catalysts with the surface intermediate species under operating conditions is critical for updating the understanding of structure–performance relationships.Here,we probe the electrochemical potentialdependent surface structures and adsorbed intermediates on PtRu binary alloy nanocatalysts to revisit its synergistic mechanisms for CO electrooxidation enhanced activity.In-situ spectral characteristics by using modified shell-isolated nanoparticle-enhanced Raman spectroscopy,show that in acidic solution,when the potential is positively scanned from 0.1 V to 1.5 V relative to reversible hydrogen electrode(RHE),the surface of the alloy catalyst evolves from metallic PtRu to adsorbed oxygen gradually covering and accumulating on Ru sites(denoted as PtRuO_(x),x≤2),forming segregated RuO_(2),and finally forming a threedimensional oxide layer(denoted as 3D PtRuO_(4)).Moreover,molecular evidence associated with periodic density functional theory calculations reveals that electronic effects promote ruthenium to become more oxidizable and oxophilic.In particular,we found here that ^(*)O and ^(*)OH at surface RuO_(x) sites are highly efficient CO oxidation active species in comparison to the same entities adsorbed on metallic Ru sites.This work sheds light on the complex surface dynamic process of practical Pt-based binary nanocatalysts and improves the understanding of synergistic mechanism for the development of fuel cell devices.

Recent progress and prospects of electrolytes for electrocatalytic nitrogen reduction toward ammonia

Electrochemical nitrogen reduction reaction(ENRR) provides a promising strategy to achieve sustainable synthesis of ammonia. However, despite great efforts devoted to this research field, the problems such as low energy efficiency and weak selectivity still impede its practical implementation. Most of the research to date has been concentrated on creating sophisticated electrocatalysts, and adequate knowledge of electrolytes is still lacking. Herein, the recent progress in electrolytes for ENRR, including alkaline, neutral,acidic, water-in-salt, organic, ionic liquid, and mixed water-organic electrolytes, is thoroughly reviewed to obtain an in-depth understanding of their effects on electrocatalytic performance. Recently developed representative electrocatalysts in various types of electrolytes are also introduced, and future research priorities of different electrolytes are proposed to develop new and efficient ENRR systems.

Well-construction of Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 core-shell hetero-structure with efficient photocatalytic activity towards tetracycline under restricted space

Nowadays,efficient removal of antibiotic(e.g.tetracycline,TC) from water bodies has been of great global concern.Hereby,a novel Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 photo-catalyst was first synthesized by a facile selfassembly in-situ growth method.Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 exhibits a remarkable photocatalytic activity towards TC under visible-light driven with a rapid rate constant of 1.5 × 10^(-2)min^(-1), and a removal efficiency of 81.2%,which is superior to some catalysts in the literature.Importantly,the photocatalytic activity of Zn_(2)SnO_(4)/SnO_(2)@ZIF-8 could still remain ~77% after the fifth cycle,indicating its good stability and reusability.The remarkable performances of adsorption and photocatalytic were attributed to associative effects of catalytic activity of Zn_(2)SnO_(4)/SnO_(2)and the unique porous nanostructure and stability of ZIF-8.This work could aid the future design and preparation of novel MOFs composite catalysts for efficient elimination of antibiotics from water.

A Series of Lanthanide-organic Frameworks Constructed by Ln_4(OH)_4 Clusters and Mixed Ligands

Three new lanthanide-organic compounds, namely, [Ln_2(OH)_2(oba)(2-pc)_2]n(Ln =Er(1), Ho(2), and Dy(3))(oba = 4,4?-oxybis(benzoate), 2-pc = 2-pyrazinecarboxylic acid) have been obtained under hydrothermal conditions. These compounds are isostructural and exhibit 2 D layered structures by incorporating [Ln_4(μ_3-OH)_4]^(8+) clusters and the mixed linkers of oba and 2-pc. It is interesting that decarboxylation occurred in the ortho position and 2,3-pyrazinedicarboxylic acid was partially transformed into 2-pc under hydrothermal conditions. Compound 3 emits a typical Dy^(3+) emission spectrum. Furthermore, the PXRD, TGA and IR spectra were also studied.

DNA-binding Studies of Two Silver(I)-sulfonate Complexes Constructed by In Situ Reaction

Two silver（I）-sulfonate complexes,[Ag（NO3）（4,4＇-bipy）][Ag（HL）（4,4＇-bipy）]·2H2O（1） and[Ag（H2O）（4,4＇-bipy）][AgL（4,4＇-bipy）]·2H2O（2）,have been synthesized by in situ reaction（H2L = 2-formylbenzenesulfonic acid,4,4-bipy = 4,4-bipyridine）.1 displays two parallel 1D chains expending to a 3D supramolecule by n—n interactions and O-H…O hydrogen bonds,in which the[Ag（NO3）]or[Ag（HL）]units are joined by bridging 4,4＇-bipy molecules,respectively.The interactions between the complexes and DNA were studied by means of fluorescence spectra and surface-enhanced Raman scattering（SERS） spectra.The special configuration and intercalation effects between 1 and DNA are stronger than that between 2 and DNA.

Recent Advances in Domino Synthesis of Fused Polycyclic N-Heterocycles Based on Intramolecular Alkyne Hydroamination under Copper Catalysis

Fused polycyclic N-heterocycles are very important scaffolds in biomedicinal chemistry and materials science.Intramolecular alkyne hydroamination is a powerful method for the construction of N-heterocycles.In the last two decades,copper-catalyzed domino reactions based on intramolecular alkyne hydroamination has emerged as a robust strategy for assembling various fused polycyclic N-heterocycles.Great progress has been achieved in this area.This short review covers the advances made in copper-catalyzed domino synthesis of fused polycyclic N-heterocycles based on the strategy from 2008 to 2023,and will hopefully serve as an inspiration towards the exploration of new copper-catalyzed versions of the transformation.The domino transformations are introduced and discussed from five aspects according to the different key processes involved in these reactions.

Strategies for improving the photocatalytic performance of metal-organic frameworks for CO_(2) reduction: A review

Photocatalytic CO_(2)reduction is an appealing strategy for mitigating the environmental effects of greenhouse gases while simultaneously producing valuable carbon-neutral fuels.Numerous attempts have been made to produce effective and efficient photocatalysts for CO_(2)reduction. In contrast, the selection of competitive catalysts continues to be a substantial hindrance and a considerable difficulty in the development of photocatalytic CO_(2)reduction. It is vital to emphasize different techniques for building effective photocatalysts to improve CO_(2)reduction performance in order to achieve a long-term sustainability. Metalorganic frameworks(MOFs) are recently emerging as a new type of photocatalysts for CO_(2)reduction due to their excellent CO_(2)adsorption capability and unique structural characteristics. This review examines the most recent breakthroughs in various techniques for modifying MOFs in order to improve their efficiency of photocatalytic CO_(2)reduction. The advantages of MOFs using as photocatalysts are summarized, followed by different methods for enhancing their effectiveness for photocatalytic CO_(2)reduction via partial ion exchange of metal clusters, design of bimetal clusters, the modification of organic linkers,and the embedding of metal complexes. For integrating MOFs with semiconductors, metallic nanoparticles(NPs), and other materials, a number of different approaches have been also reviewed. The final section of this review discusses the existing challenges and future prospects of MOFs as photocatalysts for CO_(2)reduction. Hopefully, this review can stimulate intensive research on the rational design and development of more effective MOF-based photocatalysts for visible-light driven CO_(2)conversion.

Decoration of CdMoO_(4) micron polyhedron with Pt nanoparticle and their enhanced photocatalytic performance in N_(2) fixation and water purification

This study aimed to prepare and apply a novel Pt/CdMoO_(4) composite photocatalyst for photocatalytic N2 fixation and tetracycline degradation. The Pt/CdMoO_(4) composite was subjected to comprehensive investigation on the morphology, structure, optical properties, and photoelectric chemical properties. The results demonstrate the dispersion of Pt nanoparticles on the CdMoO_(4) surface. Close contact between CdMoO_(4) and Pt was observed, resulting in the formation of a heterojunction structure at their contact region. Density functional theory calculation and Mott-Schottky analysis revealed that Pt possesses a higher work function value than CdMoO_(4), resulting in electron drift from CdMoO_(4) to Pt and the formation of a Schottky barrier. The presence of this barrier increases the separation efficiency of electron-hole pairs, thereby improving the performance of the Pt/CdMoO_(4) composite in photocatalysis. When exposed to simulated sunlight, the optimal Pt/CdMoO_(4) catalyst displayed a photocatalytic nitrogen fixation rate of 443.7 μmol·L‒^(1)·g‒^(1)·h‒^(1), which is 3.2 times higher than that of pure CdMoO_(4). In addition, the composite also exhibited excellent performance in tetracycline degradation, with hole and superoxide species identified as the primary reactive species. These findings offer practical insights into designing and synthesizing efficient photocatalysts for photocatalytic nitrogen fixation and antibiotics removal.

Synthesis and molecular recognition characteristics of a tetrapodal benzene cage

In this contribution,we describe the preparation and recognition characteristics of a novel tetrapodal benzene cage(1).The cage can express a wide recognition range without losing selectivity for the object of appropriate size and functional groups.The key to obtaining the desired structural isomer of 1 is the synthesis and isolation of the o-bis(bromomethyl)benzene precursor(5).Three distinct guests,F^(−)(ex-tremely small size),d-lactate(appropriate size)and l-Asp(branched shape),were selected as examples to demonstrate the recognition characteristics of 1.By NMR titration studies,they all expressed good binding affinity(K>10^(5) L/mol)in competitive medium(10%DMSO/THF),indicating that 1 has a wide recognition scope.The highest binding constant was observed for d-lactate,revealing that 1 has good selectivity for d-lactate versus F^(−)and L-Asp.Moreover,the NMR titration study of F^(−)in DMSO indicates 1 can achieve different binding modes(1:1 and 2:1 guest-host)for small-sized guests,which allows for the further development of binary binding properties and thereafter applications in the field of catalysis.