Designing Fischer-Tropsch synthesis(FTS)catalysts to selectively produce liquid hydrocarbon fuels is a crucial challenge.Herein,we selectively introduced Co nanoparticles(NPs)into the micropores and mesopores of an or...Designing Fischer-Tropsch synthesis(FTS)catalysts to selectively produce liquid hydrocarbon fuels is a crucial challenge.Herein,we selectively introduced Co nanoparticles(NPs)into the micropores and mesopores of an ordered mesoporous MFI zeolite(OMMZ)through impregnation,which controlled the carbon number distribution in the FTS products by tuning the position of catalytic active sites in differently sized pores.The Co precursors coordinated by acetate with a size of 9.4×4.2×2.5Åand by 2,2'-bipyridine with a size of 9.5×8.7×7.9Å,smaller and larger than the micropores(ca.5.5Å)of MFI,made the Co species incorporated in OMMZ's micropores and mesopores,respectively.The carbon number products synthesized with the Co NPs confined in mesopores were larger than that in micropores.The high jet and diesel selectivities of 66.5%and 65.3%were achieved with Co NPs confined in micropores and mesopores of less acidic Na-type OMMZ,respectively.Gasoline and jet selectivities of 76.7%and 70.8%were achieved with Co NPs confined in micropores and mesopores of H-type OMMZ with Brönsted acid sites,respectively.A series of characterizations revealed that the selective production of diesel and jet fuels was due to the C-C cleavage suppressing of heavier hydrocarbons by the Co NPs located in mesopores.展开更多
In the continuous development of electrochemical CO_(2) reduction (ECR), Cu-based electrocatalysts have received great attention, due to their unique ability to produce high value-added multicarbon products. Of partic...In the continuous development of electrochemical CO_(2) reduction (ECR), Cu-based electrocatalysts have received great attention, due to their unique ability to produce high value-added multicarbon products. Of particular interest are various Cu-comprising nanocrystals, not only because they usually show better catalytic properties than bulk materials, but also because their well-defined structures and highly tunable compositions facilitate in-depth mechanistic studies. This review aims to summarize the latest developments of electrocatalysts for ECR, with a focus on systems using Cu-comprising nanocrystals. We first give a general introduction to the field of ECR, covering the significance of this process, reaction mechanisms, catalyst evaluation criteria, and electrolytic cell configurations. Next, we discuss Cu-comprising nanocrystals developed for ECR by categorizing them into four groups: monometallic copper, copper-containing bimetals/multimetals, copper compounds, and copper–metal oxide hybrids;among these groups, we choose representative examples for detailed discussion on the synthetic methods, structural and compositional reaction sensitivities, and catalyst evolution during ECR. In the last section, we outline the challenges in this field from the fundamental and applicative aspects, and give perspectives on the expansion of catalyst varieties, the identification and preservation of active sites, and the exploration of industrially relevant operations for these nanocrystals. We hope the insights provided in this review will inspire the design and development of next-generation catalysts for ECR.展开更多
As one of the most widely used characterization tools in materials science,(scanning)transmission electron microscopy((S)TEM)has the unique ability to directly image specimens with atomic resolution.Compared to diffra...As one of the most widely used characterization tools in materials science,(scanning)transmission electron microscopy((S)TEM)has the unique ability to directly image specimens with atomic resolution.Compared to diffraction-based techniques,the main advantage of(S)TEM imaging is that in addition to the periodic average structures of crystalline materials,it can be used to probe nonperiodic local structures such as surfaces,interfaces,dopants,and defects,which have crucial impacts on material properties.However,many crystalline materials are extremely sensitive to electron beam irradiation,which can only withstand dozens(or even fewer)of electrons per square angstrom before they undergo structural damage.Although using electron doses lower than the thresholds can in principle preserve their structures,the thus acquired images are too noisy to be useful.Consequently,high-resolution imaging of the inherent structures of such electron beam-sensitive materials using(S)TEM is a longstanding challenge.In recent years,the advances in electron detectors and image-acquisition methods have enabled high-resolution(S)TEM with ultralow electron doses,largely overcoming this challenge.A series of highly electron beam-sensitive materials that are traditionally considered impossible to be imaged with(S)TEM,including metal organic frameworks(MOFs),covalent organic frameworks(COFs),organic−inorganic hybrid halide perovskites,and supramolecular crystals,have been successfully imaged at atomic resolutions.This technological advance has greatly expanded the application range of electron microscopy.This Account focuses on our recent works pertaining to the high-resolution imaging of electron beam-sensitive materials using very low electron doses.We first explain that the use of direct-detection electron-counting(DDEC)cameras provides the hardware basis for successful low-dose high-resolution TEM(HRTEM).Subsequently,we introduce a suite of methods to address the challenges peculiar to low-dose HRTEM,including rapid search for crystal zone axes,precise alignment of the image stack,and accurate determination of the defocus value.These methods,combined with the use of a DDEC camera,ensure efficient imaging of electron beam-sensitive crystalline materials in the TEM mode.Moreover,we demonstrate that integrated differential phase contrast STEM(iDPC-STEM)is an effective method for acquiring directly interpretable atomic-resolution images under low-dose conditions.In addition,we share our views on the great potential of four-dimensional STEM(4D-STEM)in imaging highly electron beamsensitive materials and provide preliminary simulation results to demonstrate its feasibility.Finally,we discuss the significance of developing(S)TEM specimen preparation techniques applicable for sensitive materials and the advantages of using the cryogenic focused ion beam(cryo-FIB)technique for this purpose.展开更多
The complex-architectured NiFe-LDH@FeOOH negative material was first prepared by simple two-step hydrothermal method.In this study,the porous nanostructure of FeOOH nanosheets features a large number of accessible cha...The complex-architectured NiFe-LDH@FeOOH negative material was first prepared by simple two-step hydrothermal method.In this study,the porous nanostructure of FeOOH nanosheets features a large number of accessible channels to electroactive sites and the two-dimensional layered structure of NiFe-LDH nanosheets have an open spatial structure with high specific surface area,which enhance the diffusion of ions in the active material.Benefited from above advantages,the excellent electrochemical properties were demonstrated.NiFe-LDH@FeOOH nanocomposites present high specific capacitance(1195 F/g at a current density of 1 A/g),lower resistance and well cycling performance(90.36% retention after 1000 cycles).Furthermore,the NiFe-LDH@MnO2//NiFe-LDH@FeOOH supercapacitor exhibits22.68 Wh/kg energy density at 750 W/kg power density,demonstrating potential application in energy storage devices.展开更多
Aluminosilicate small pore zeolites belonging to ABC-6 family play crucially important roles in the high methanol conversion with the high selectivity of light olefins,gas separation and storage,and selective catalyti...Aluminosilicate small pore zeolites belonging to ABC-6 family play crucially important roles in the high methanol conversion with the high selectivity of light olefins,gas separation and storage,and selective catalytic reduction of NO_(x).In this work,we report a general method,called the epitaxial growth approach,for designing ABC-6 family small pore zeolites.It is mainly realized through the epitaxial growth on the nonporous SOD-type zeolite in the presence of inorganic cations(Na^(+)and K^(+))combined with a variety of organic structure directing agents(OSDAs).In this case,a series of ABC-6 family small pore zeolites such as ERI-,SWY-,LEV-,AFX-,and PTT-type zeolites have been successfully synthesized within a few hours.More importantly,the advanced focused ion beam(FIB)and the low-dose high-resolution transmission electron microscopy(HRTEM)imaging technique have been utilized for unraveling the zeolite heterojunction at the atomic level during the epitaxial growth process.It turns out(222)crystallographic planes of the SOD-type zeolite substrate provide unique pre-building units,which facilitate the growth of targeted ABC-6 family small pore zeolites along its c-axis.Moreover,the morphologies of ERI-type zeolite can also be tuned through the epitaxial growth approach,achieving a longer lifetime in the methanol conversion.展开更多
Selective conversion of fructose to 1,2-propanediol(1,2-PDO)is considered as a sustainable and cost-effective alternative to petroleum-based processes,however,this approach still faces challenges associated with low e...Selective conversion of fructose to 1,2-propanediol(1,2-PDO)is considered as a sustainable and cost-effective alternative to petroleum-based processes,however,this approach still faces challenges associated with low efficiency and harsh reaction conditions.Here,we have successfully synthesized a novel bifunctional Ru-WO_(x)-MgO_(y) catalyst through a facile'one-pot'solvothermal method.Remarkably,this catalyst exhibits exceptional catalytic performances in the conversion of fructose to 1,2-PDO under mild reaction conditions.The yield of 1,2-PDO is up to 56.2%at 140°C for 4 h under an ultra-low hydrogen pressure of only 0.2 MPa,surpassing the reported results in recent literature(below 51%).Comprehensive characterizations and density functional theory(DFT)calculations reveal that the presence of oxygen vacancies in the Ru-WO_(x)-MgO_(y) catalyst,serving as active acidic sites,facilitates the chemoselective cleavage of C-C bonds in fructose,which leads to the generation of active intermediates and ultimately resulted in the high yield of 1,2-PDO.展开更多
Water is considered to be an inhibitor of CO oxidation.The mechanism of retarding the reaction is thought to contribute to the practical application of CO oxidation,which is investigated by constructing the coupling o...Water is considered to be an inhibitor of CO oxidation.The mechanism of retarding the reaction is thought to contribute to the practical application of CO oxidation,which is investigated by constructing the coupling of Au nanoparticles and defective CuO to form metal-support interactions(MSI)and oxygen vacancies(OVs).The introduction of Au forms a new CO adsorption site,which successfully solves the competitive adsorption problem of CO with H2O and O_(2).Due to the coupling of MSI and OVs,the reduced ability of catalyst and the activation and migration ability of oxygen are enhanced simultaneously.Au-CuO has the ability to oxidize CO at room temperature with high stability under a humid environment.Theoretical calculation confirmed the competitive adsorption and the influence of MSI and OVs coupling on the catalyst performance.The mechanism of water resistance in CO catalytic oxidation was also explained.展开更多
Electrocatalytic co-reduction of CO_(2)and nitrate offers an attractive and sustainable pathway for urea synthesis,as it enables the simultaneous valorization of nitrogenous waste and CO_(2)into value-added chemicals....Electrocatalytic co-reduction of CO_(2)and nitrate offers an attractive and sustainable pathway for urea synthesis,as it enables the simultaneous valorization of nitrogenous waste and CO_(2)into value-added chemicals.However,achieving ambient and high-performance urea electrosynthesis remains a persistent challenge,as it requires the simultaneous activation of CO_(2)and efficient H_(2)O dissociation to supply active^(*)H for^(*)NO x hydrogenation—ultimately forming key Cand N-containing intermediates necessary for effective C-N coupling.The stringent,sequential nature of the reaction requirements continues to present substantial challenges for the rational design of advanced multifunctional catalysts.Herein,we report a creative two-in-one catalyst,bifunctional Pd-single-atom-modified Cu(Pd_(1)Cu)nanorods,to synergistically promote the adsorption and stepwise activation of dual species,that is,CO_(2)and H_(2)O,thereby effectively steering the reaction pathway toward the highly selective synthesis of urea.By integrating experimental evidence,in situ spectroscopy,and computational analyses,we clearly disclose that the atomically dispersed Pd sites kinetically favor the co-generation of^(*)CO and^(*)NH_(2)(via H_(2)O dissociation-driven proton transfer),thereby forming an optimal intermediate balance that facilitates urea synthesis.More importantly,the rationally designed Pd_(1)Cu leverages dual metal active sites to enhance C-N coupling via combined electronic and geometric effects,substantially lowering the reaction energy barrier and improving selectivity toward urea.展开更多
It is challenging and desirable to construct Pt-based nanocomposites with oxygen storage function as efficient oxygen reduction reaction(ORR)catalysts for practical proton exchange membrane fuel cells(PEMFCs).Herein,w...It is challenging and desirable to construct Pt-based nanocomposites with oxygen storage function as efficient oxygen reduction reaction(ORR)catalysts for practical proton exchange membrane fuel cells(PEMFCs).Herein,we achieve novel porous nanocomposites of PtCu_(3) nanoalloys-embedded in the PWO_(x) matrix(PtCu_(3)@PWO_(x)),which has an oxygen container feature.The PtCu_(3)@PWO_(x)/C exhibits an ultrahigh mass activity(MA)of 3.94 A·mgPt−1 for ORR,which is 26.3 times as high as the commercial Pt/C and the highest value ever reported for PtCu-based binary system.Theoretical calculations reveal that the compressive strain and d-band center downshift of Pt intrinsically contribute to the excellent ORR performance.In H_(2)-air PEMFCs at room temperature,furthermore,the PtCu_(3)@PWO_(x)/C delivers a high power density(218.6 mW·cm^(−2)),much superior to commercial Pt/C(131.6 mW·cm^(−2)).In H_(2)-O_(2) PEMFCs,PtCu_(3)@PWO_(x)/C outputs a maximum power density of 420.1 mW·cm^(−2).This work provides an effective idea for designing oxygen-storing ORR catalysts used for practical room-temperature H_(2)-air fuel cells.展开更多
The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydroph...The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydrophilic nanocomposites of Ru clusters(~1.30 nm)anchored on Na^(+),K^(+)-decorated porous carbon(Ru/Na^(+),K^(+)-PC)through hydrothermal method and subsequent annealing treatment at 500℃.The Ru/Na^(+),K^(+)-PC exhibits ultralow overpotential of 7 mV at 10 mA·cm^(-2),mass activity of 15.7 A·mgRu^(-1)at 100 mV,and long-term durability of 20,000 cycles potential cycling and 200 h chronopotentiometric measurement with a negligible decrease in activity,much superior to benchmarked commercial Pt/C.Density functional theory based calculations show that the energy barrier of H-OH bond breaking is efficiently reduced due to the presence of Na and K ions,thus favoring the Volmer step.Furthermore,the Ru/Na^(+),K^(+)-PC effectively employs solar energy for obtaining H_(2)in both alkaline water and seawater electrolyzer.This finding provides a new strategy to construct high-performance and cost-effective alkaline HER electrocatalyst.展开更多
Aqueous zinc-ion batteries(AZIBs)have attracted increasing interest due to their intrinsic safety and low cost,yet their energy density remains limited by the lack of suitable cathode materials.Covalent organic framew...Aqueous zinc-ion batteries(AZIBs)have attracted increasing interest due to their intrinsic safety and low cost,yet their energy density remains limited by the lack of suitable cathode materials.Covalent organic frameworks(COFs),with tunable porosity,structural diversity,and redox-site designability,have emerged as promising AZIBs cathodes.The integration of multiple redox-active sites,such as carbonyl(C=O)and imine(C=N)groups,enables stepwise multi-electron transfer,offering a pathway to higher capacity and voltage output.This review systematically categorizes COFs into n-type,p-type,and bipolar systems based on redox-active moieties and analyzes their charge storage behaviors through cyclic voltammetry(CV).We focus on how the spatial arrangement and electronic nature of C=O/C=N sites influence one-,two-,or three-step electron transfer,as well as Zn2+and H+co-insertion mechanisms.Electrochemical performances,redox kinetics,molecular structure,and electrolyte adaptability are also discussed in detail.By elucidating the structure-mechanism relationships of redox-active COFs,this review highlights molecular design principles that enhance redox-site utilization and energy density.The insights provided herein aim to guide the development of next-generation,high-performance organic cathodes for multi-electron AZIBs.展开更多
Efficient production of butanediols from biomass-derived feedstocks under mild reaction conditions is still of challenge.Here,we reported a highly efficient Pd-WO_(x) catalyst which was facilely synthesized by a simpl...Efficient production of butanediols from biomass-derived feedstocks under mild reaction conditions is still of challenge.Here,we reported a highly efficient Pd-WO_(x) catalyst which was facilely synthesized by a simple‘one pot’solvothermal method for the selective conversion of glucose and lignocellulosic biomass to butanediols with remarkable activity.The optimized process achieved an impressive 56.5%yield of butanediols at 180◦C within 8 h under a low hydrogen pressure of 0.6 MPa,surpassing most reported catalysts.Comprehensive characterization(H_(2)-TPR,XPS,NH3-TPD,etc.)revealed that Pd-WO_(x) not only enhanced H_(2) adsorption and activation but also possessed a higher density of acidic sites to promote selective cleavage of C-C bond in glucose structure,thereby significantly improving the efficiency of sustainable butanediols production.Furthermore,the catalyst demonstrated excellent stability over five reaction cycles.This work provides a viable and efficient strategy for sustainable biomass valorization to produce valuable butanediols.展开更多
Head and neck squamous cell carcinoma(HNSCC)is the sixth most common malignant tumor worldwide.Considering its special anatomical site and the progressive resistance to chemotherapy drugs,the development of more effec...Head and neck squamous cell carcinoma(HNSCC)is the sixth most common malignant tumor worldwide.Considering its special anatomical site and the progressive resistance to chemotherapy drugs,the development of more effective,minimally invasive and precise treatment methods is urgently needed.Nanomaterials,given their special properties,can be used as drug carrier systems to improve the therapeutic effect and reduce the adverse effects.The drug carrier systems with photothermal effect can promote the killing of cancer cells and help overcome drug resistance through heat stress.We selected dopamine,a simple raw material,and designed and synthesized three different configurations of nanopolydopamine(nPDA)nanomaterials,including nPDA balls,nPDA plates and porous nPDA balls.In addition to the self-polymerization and self-assembly,nPDA has high photothermal conversion efficiency and can be easily modified.Moreover,we loaded cisplatin into three different configurations of nPDA,creating nPDA-cis(the nano-drug carrier system with cisplatin),and comparatively studied the properties and antitumor effects of all the nPDA and nPDA-cis materials in vitro and nPDA-cis in vivo.We found that the photothermal effect of the nPDA-cis balls drug carrier system had synergistic effect with cisplatin,resulting in excellent antitumor effect and good clinical application prospects.The comparison of the three different configurations of drug carrier systems suggested the importance of optimizing the spatial configuration design and examining the physical and chemical properties in the future development of nano-drug carrier systems.In this study,we also noted the duality and complexity of the influences of heat stress on tumors in vitro and in vivo.The specific mechanisms and the synergy with chemotherapy and immunotherapy will be an important research direction in the future.展开更多
Developing highly stable and active non-Pt oxygen reduction reaction(ORR)electrocatalysts for power generation device raises great concerns and remains a challenge.Here,we report novel truncated Pd tetrahedrons(T-Pd-T...Developing highly stable and active non-Pt oxygen reduction reaction(ORR)electrocatalysts for power generation device raises great concerns and remains a challenge.Here,we report novel truncated Pd tetrahedrons(T-Pd-Ths)enclosed by{111}facets with excellent uniformity,which have both low-coordinated surface sites and distinct lattice distortions that would induce“local strain”.In alkaline electrolyte,the T-Pd-Ths/C achieves remarkable ORR specific/mass activity(SA/MA)of 2.46 mA·cm^(−2)/1.69 A·mgPd^(−1),which is 12.3/16.9 and 10.7/14.1 times higher than commercial Pd/C and Pt/C,respectively.The T-Pd-Ths/C also exhibits high in-situ carbon monoxide(CO)tolerance and 50,000 cycles durability with an activity loss of 7.69%and morphological stability.The rotating ring-disk electrode(RRDE)measurements show that a 4-electron process occurs on T-PdThs/C.Theoretical calculations demonstrate that the low-coordinated surface sites contribute largely to the enhancement of ORR activity.In actual direct methanol fuel cell(DMFC)device,the T-Pd-Ths/C delivers superior open-circuit voltage(OCV)and peak power density(PPD)to commercial Pt/C from 25 to 80℃,and the maximum PPD can reach up to 163.7 mW·cm−2.This study demonstrates that the T-Pd-Ths/C holds promise as alternatives to Pt for ORR in DMFC device.展开更多
Halide perovskite light emitting diodes(LEDs)have gained great progress in recent years.However,mixed-halide perovskites for blue LEDs usually suffer from electroluminescence(EL)spectra shift at a high applied voltage...Halide perovskite light emitting diodes(LEDs)have gained great progress in recent years.However,mixed-halide perovskites for blue LEDs usually suffer from electroluminescence(EL)spectra shift at a high applied voltage or current density,limiting their efficiency.In this work,we report a strategy of using single-layer perovskite quantum dots(QDs)film to tackle the electroluminescence spectra shift in pure-blue perovskite LEDs and improve the LED efficiency by co-doping copper and potassium in the mixed-halide perovskite QDs.As a result,we obtained pure-blue halide perovskite QD-LEDs with stable EL spectra centred at 469 nm even at a current density of 1,617 mA·cm^(−2).The optimal device presents a maximum external quantum efficiency(EQE)of 2.0%.The average maximum EQE and luminance of the LEDs are 1.49%and 393 cd·m^(−2),increasing 62%and 66%compared with the control LEDs.Our study provides an effective strategy for achieving spectra-stable and highly efficient pure-blue perovskite LEDs.展开更多
The large-scale preparation ofmonolayer two-dimensional(2D)material remains a great challenge,which hinders its real-world applications.Herein,we report a novel layered metal–organic framework(MOF),IPM-1,whichwas syn...The large-scale preparation ofmonolayer two-dimensional(2D)material remains a great challenge,which hinders its real-world applications.Herein,we report a novel layered metal–organic framework(MOF),IPM-1,whichwas synthesized froma cage-like organic linker,with extremely weak interlaminar interaction.When subjected to external disturbance,IPM-1 degenerated into an intermediate state between the crystalline and amorphous phase,in which the layers retain the inplane two-dimensional periodic structure but aremisaligned in the third dimension,leading to the loss of apparent porosity and crystallinity.This amorphous IPM-1 is readily exfoliated at gramscale into crystalline 2D nanosheets with a thickness of 1.15 nm,excellent thickness homogeneity,lateral size up to 10μm,and restored microporosity.IPM-1 nanosheets exhibit high chemical stability and catalytic activity in the oxidation of alcohol,combining the advantages of both homogeneous and heterogeneous catalyst.This work underscores that MOFs without apparent crystallinity can be ideal precursors for the successful preparation of 2D crystalline monolayer nanosheets.展开更多
The development of cathode oxygen reduction reaction(ORR)catalysts with high characteristics for practical,direct methanol fuel cells(DMFCs)has continuously increased the attention of researchers.In this work,interfac...The development of cathode oxygen reduction reaction(ORR)catalysts with high characteristics for practical,direct methanol fuel cells(DMFCs)has continuously increased the attention of researchers.In this work,interface-rich Au-doped PdBi(PdBiAu)branched one-dimensional(1D)alloyed nanochains assembled by sub-6.5 nm particles have been prepared,exhibiting an ORR mass activity(MA)of 6.40 A·mgPd^(−1) and long-term durability of 5,000 cycles in an alkaline medium.The MA of PdBiAu nanochains is 46 times and 80 times higher than that of commercial Pt/C(0.14 A·mgPt^(−1))and Pd/C(0.08 A·mgPd^(−1)).The MA of binary PdBi nanochains also reaches 5.71 A·mgPd^(−1).Notably,the PdBiAu nanochains exhibit high in-situ carbon monoxide poisoning resistance and high methanol tolerance.In actual DMFC device tests,the PdBiAu nanochains enhance power density of 140.1 mW·cm^(−2)(in O_(2))/112.4 mW·cm^(−2)(in air)and durability compared with PdBi nanochains and Pt/C.The analysis of the structure–function relationship indicates that the enhanced performance of PdBiAu nanochains is attributed to integrated functions of surficial defect-rich 1D chain structure,improved charge transfer capability,downshift of the d-band center of Pd,as well as the synergistic effect derived from“Pd-Bi”and/or“Pd-Au”dual active sites.展开更多
A challenge facing scientists is the rational synthesis of highly crystalline covalent organic frameworks(COFs),consisting of both n-type and p-type redox-active units,as cathodes for high-performance lithium-ion batt...A challenge facing scientists is the rational synthesis of highly crystalline covalent organic frameworks(COFs),consisting of both n-type and p-type redox-active units,as cathodes for high-performance lithium-ion batteries(LIBs).Herein,we apply reticular chemistry to regulate a COF platform with the kgm topology via an in-situ postsynthetic oxidation strategy.We integrate both n-type and p-type redox-active units into a resulting COF skeleton—TPDA-DQTA-COF,and this COF-based cathode shows an enhanced performance for LIBs compared to the parent TPDA-DMTA-COF.On account of dual redox-active units for PF6−/Li+costorage,the TPDADQTA-COF cathode presents the highly reversible capacity of 308 mAh g−1 at 0.2 A g^(−1) and the high energy density of 800 Wh kg^(−1).The long-term cycling experiment reveals a capacity retention of 91%after 200 cycles at a low current density of 0.5 A g^(−1).The combined Fourier transform infrared and X-ray photoelectron spectroscopy experiments suggest that the in-situ electrochemical oxidation from the C-OH to the C=O group of COFs occurs during the charging process.We believe our study demonstrates that the atomic-level modification of functional groups in COF-based cathode materials has a significant impact on the macroscopic performance of lithium-ion storage,clearly illustrating the structure-property relationship.展开更多
文摘Designing Fischer-Tropsch synthesis(FTS)catalysts to selectively produce liquid hydrocarbon fuels is a crucial challenge.Herein,we selectively introduced Co nanoparticles(NPs)into the micropores and mesopores of an ordered mesoporous MFI zeolite(OMMZ)through impregnation,which controlled the carbon number distribution in the FTS products by tuning the position of catalytic active sites in differently sized pores.The Co precursors coordinated by acetate with a size of 9.4×4.2×2.5Åand by 2,2'-bipyridine with a size of 9.5×8.7×7.9Å,smaller and larger than the micropores(ca.5.5Å)of MFI,made the Co species incorporated in OMMZ's micropores and mesopores,respectively.The carbon number products synthesized with the Co NPs confined in mesopores were larger than that in micropores.The high jet and diesel selectivities of 66.5%and 65.3%were achieved with Co NPs confined in micropores and mesopores of less acidic Na-type OMMZ,respectively.Gasoline and jet selectivities of 76.7%and 70.8%were achieved with Co NPs confined in micropores and mesopores of H-type OMMZ with Brönsted acid sites,respectively.A series of characterizations revealed that the selective production of diesel and jet fuels was due to the C-C cleavage suppressing of heavier hydrocarbons by the Co NPs located in mesopores.
基金This work was supported by the Thousand Talents Program for Distinguished Young Scholars,the Fundamental Research Funds for the Central Universities(2020CDJQY-A072)the Venture and Innovation Support Program for Chongqing Overseas Returnees(cx2020107).
文摘In the continuous development of electrochemical CO_(2) reduction (ECR), Cu-based electrocatalysts have received great attention, due to their unique ability to produce high value-added multicarbon products. Of particular interest are various Cu-comprising nanocrystals, not only because they usually show better catalytic properties than bulk materials, but also because their well-defined structures and highly tunable compositions facilitate in-depth mechanistic studies. This review aims to summarize the latest developments of electrocatalysts for ECR, with a focus on systems using Cu-comprising nanocrystals. We first give a general introduction to the field of ECR, covering the significance of this process, reaction mechanisms, catalyst evaluation criteria, and electrolytic cell configurations. Next, we discuss Cu-comprising nanocrystals developed for ECR by categorizing them into four groups: monometallic copper, copper-containing bimetals/multimetals, copper compounds, and copper–metal oxide hybrids;among these groups, we choose representative examples for detailed discussion on the synthetic methods, structural and compositional reaction sensitivities, and catalyst evolution during ECR. In the last section, we outline the challenges in this field from the fundamental and applicative aspects, and give perspectives on the expansion of catalyst varieties, the identification and preservation of active sites, and the exploration of industrially relevant operations for these nanocrystals. We hope the insights provided in this review will inspire the design and development of next-generation catalysts for ECR.
文摘As one of the most widely used characterization tools in materials science,(scanning)transmission electron microscopy((S)TEM)has the unique ability to directly image specimens with atomic resolution.Compared to diffraction-based techniques,the main advantage of(S)TEM imaging is that in addition to the periodic average structures of crystalline materials,it can be used to probe nonperiodic local structures such as surfaces,interfaces,dopants,and defects,which have crucial impacts on material properties.However,many crystalline materials are extremely sensitive to electron beam irradiation,which can only withstand dozens(or even fewer)of electrons per square angstrom before they undergo structural damage.Although using electron doses lower than the thresholds can in principle preserve their structures,the thus acquired images are too noisy to be useful.Consequently,high-resolution imaging of the inherent structures of such electron beam-sensitive materials using(S)TEM is a longstanding challenge.In recent years,the advances in electron detectors and image-acquisition methods have enabled high-resolution(S)TEM with ultralow electron doses,largely overcoming this challenge.A series of highly electron beam-sensitive materials that are traditionally considered impossible to be imaged with(S)TEM,including metal organic frameworks(MOFs),covalent organic frameworks(COFs),organic−inorganic hybrid halide perovskites,and supramolecular crystals,have been successfully imaged at atomic resolutions.This technological advance has greatly expanded the application range of electron microscopy.This Account focuses on our recent works pertaining to the high-resolution imaging of electron beam-sensitive materials using very low electron doses.We first explain that the use of direct-detection electron-counting(DDEC)cameras provides the hardware basis for successful low-dose high-resolution TEM(HRTEM).Subsequently,we introduce a suite of methods to address the challenges peculiar to low-dose HRTEM,including rapid search for crystal zone axes,precise alignment of the image stack,and accurate determination of the defocus value.These methods,combined with the use of a DDEC camera,ensure efficient imaging of electron beam-sensitive crystalline materials in the TEM mode.Moreover,we demonstrate that integrated differential phase contrast STEM(iDPC-STEM)is an effective method for acquiring directly interpretable atomic-resolution images under low-dose conditions.In addition,we share our views on the great potential of four-dimensional STEM(4D-STEM)in imaging highly electron beamsensitive materials and provide preliminary simulation results to demonstrate its feasibility.Finally,we discuss the significance of developing(S)TEM specimen preparation techniques applicable for sensitive materials and the advantages of using the cryogenic focused ion beam(cryo-FIB)technique for this purpose.
基金financial support from the National Natural Science Foundation of China(Nos.21576034 and 51908092)the State Education Ministry and Fundamental Research Funds for the Central Universities(Nos.2019CDQYCL042,2019CDXYCL0031,2018CDYJSY0055,106112017CDJQJ138802,106112017CDJSK04XK11 and 106112017CDJXSYY0001)the Joint Funds of the National Natural Science Foundation of China-Guangdong(No.U1801254)。
文摘The complex-architectured NiFe-LDH@FeOOH negative material was first prepared by simple two-step hydrothermal method.In this study,the porous nanostructure of FeOOH nanosheets features a large number of accessible channels to electroactive sites and the two-dimensional layered structure of NiFe-LDH nanosheets have an open spatial structure with high specific surface area,which enhance the diffusion of ions in the active material.Benefited from above advantages,the excellent electrochemical properties were demonstrated.NiFe-LDH@FeOOH nanocomposites present high specific capacitance(1195 F/g at a current density of 1 A/g),lower resistance and well cycling performance(90.36% retention after 1000 cycles).Furthermore,the NiFe-LDH@MnO2//NiFe-LDH@FeOOH supercapacitor exhibits22.68 Wh/kg energy density at 750 W/kg power density,demonstrating potential application in energy storage devices.
基金supported by National Key Research and Development Project of China(No.2022YFE0113800)National Natural Science Foundation of China(Nos.22288101,21972136,21991090 and 21991091)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(No.QYZDB-SSW-JSC040)。
文摘Aluminosilicate small pore zeolites belonging to ABC-6 family play crucially important roles in the high methanol conversion with the high selectivity of light olefins,gas separation and storage,and selective catalytic reduction of NO_(x).In this work,we report a general method,called the epitaxial growth approach,for designing ABC-6 family small pore zeolites.It is mainly realized through the epitaxial growth on the nonporous SOD-type zeolite in the presence of inorganic cations(Na^(+)and K^(+))combined with a variety of organic structure directing agents(OSDAs).In this case,a series of ABC-6 family small pore zeolites such as ERI-,SWY-,LEV-,AFX-,and PTT-type zeolites have been successfully synthesized within a few hours.More importantly,the advanced focused ion beam(FIB)and the low-dose high-resolution transmission electron microscopy(HRTEM)imaging technique have been utilized for unraveling the zeolite heterojunction at the atomic level during the epitaxial growth process.It turns out(222)crystallographic planes of the SOD-type zeolite substrate provide unique pre-building units,which facilitate the growth of targeted ABC-6 family small pore zeolites along its c-axis.Moreover,the morphologies of ERI-type zeolite can also be tuned through the epitaxial growth approach,achieving a longer lifetime in the methanol conversion.
基金the financial support from the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0458)the State Key Laboratory of Coal Mine Disaster Dynamics and Control(2011DA105287-MS202203)+4 种基金the Joint Fund for Innovation and Development of Chongqing(CSTB2022NSCQ-LZX0030)the financial support from the National Natural Science Foundation of China(22168027 and 22308169)the financial support from the Natural Science Foundation of Chongqing(cstc2021jcyj-msxmX0741)the financial support from the National Natural Science Foundation of China(22105028)the Natural Science Foundation of Chongqing(cstc2021jcyj-msxmX0572)。
文摘Selective conversion of fructose to 1,2-propanediol(1,2-PDO)is considered as a sustainable and cost-effective alternative to petroleum-based processes,however,this approach still faces challenges associated with low efficiency and harsh reaction conditions.Here,we have successfully synthesized a novel bifunctional Ru-WO_(x)-MgO_(y) catalyst through a facile'one-pot'solvothermal method.Remarkably,this catalyst exhibits exceptional catalytic performances in the conversion of fructose to 1,2-PDO under mild reaction conditions.The yield of 1,2-PDO is up to 56.2%at 140°C for 4 h under an ultra-low hydrogen pressure of only 0.2 MPa,surpassing the reported results in recent literature(below 51%).Comprehensive characterizations and density functional theory(DFT)calculations reveal that the presence of oxygen vacancies in the Ru-WO_(x)-MgO_(y) catalyst,serving as active acidic sites,facilitates the chemoselective cleavage of C-C bonds in fructose,which leads to the generation of active intermediates and ultimately resulted in the high yield of 1,2-PDO.
基金supported by the National Natural Science Foundation of China(Grant nos.51772183 and 52072230).
文摘Water is considered to be an inhibitor of CO oxidation.The mechanism of retarding the reaction is thought to contribute to the practical application of CO oxidation,which is investigated by constructing the coupling of Au nanoparticles and defective CuO to form metal-support interactions(MSI)and oxygen vacancies(OVs).The introduction of Au forms a new CO adsorption site,which successfully solves the competitive adsorption problem of CO with H2O and O_(2).Due to the coupling of MSI and OVs,the reduced ability of catalyst and the activation and migration ability of oxygen are enhanced simultaneously.Au-CuO has the ability to oxidize CO at room temperature with high stability under a humid environment.Theoretical calculation confirmed the competitive adsorption and the influence of MSI and OVs coupling on the catalyst performance.The mechanism of water resistance in CO catalytic oxidation was also explained.
基金the funding support from the National Natural Science Foundation of China(22373080)Fujian Pro-vincial Natural Science Foundation of China(2024J08008)+6 种基金the funding support from the National Natural Science Foundation of China(22402163)Fujian Provincial Science and Technology Program for International Cooperation(2025I0002)Natural Science Foundation of Xiamen,China(3502Z202472001)the funding support from the National Natural Science Foundation of China(22078274)the funding support from the Funda-mental Research Funds for the Central Universities(20720240054)Nan-Qiang Youth Scholar Program of Xiamen UniversityXiaomi Young Talents Program/Xiaomi Foundation。
文摘Electrocatalytic co-reduction of CO_(2)and nitrate offers an attractive and sustainable pathway for urea synthesis,as it enables the simultaneous valorization of nitrogenous waste and CO_(2)into value-added chemicals.However,achieving ambient and high-performance urea electrosynthesis remains a persistent challenge,as it requires the simultaneous activation of CO_(2)and efficient H_(2)O dissociation to supply active^(*)H for^(*)NO x hydrogenation—ultimately forming key Cand N-containing intermediates necessary for effective C-N coupling.The stringent,sequential nature of the reaction requirements continues to present substantial challenges for the rational design of advanced multifunctional catalysts.Herein,we report a creative two-in-one catalyst,bifunctional Pd-single-atom-modified Cu(Pd_(1)Cu)nanorods,to synergistically promote the adsorption and stepwise activation of dual species,that is,CO_(2)and H_(2)O,thereby effectively steering the reaction pathway toward the highly selective synthesis of urea.By integrating experimental evidence,in situ spectroscopy,and computational analyses,we clearly disclose that the atomically dispersed Pd sites kinetically favor the co-generation of^(*)CO and^(*)NH_(2)(via H_(2)O dissociation-driven proton transfer),thereby forming an optimal intermediate balance that facilitates urea synthesis.More importantly,the rationally designed Pd_(1)Cu leverages dual metal active sites to enhance C-N coupling via combined electronic and geometric effects,substantially lowering the reaction energy barrier and improving selectivity toward urea.
基金supported by the National Natural Science Foundation of China(No.21571038)Foundation of Guizhou Province(No.2019-5666)+3 种基金Education Department of Guizhou Province(No.2021312)State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University,No.2011DA105287-ZR202101)State Key Laboratory of Physica Chemistry of Solid Surfaces(Xiamen University,No.202009)the Open Fund of the Key Lab of Organic Optoelectronics&Molecular Engineering(Tsinghua University).
文摘It is challenging and desirable to construct Pt-based nanocomposites with oxygen storage function as efficient oxygen reduction reaction(ORR)catalysts for practical proton exchange membrane fuel cells(PEMFCs).Herein,we achieve novel porous nanocomposites of PtCu_(3) nanoalloys-embedded in the PWO_(x) matrix(PtCu_(3)@PWO_(x)),which has an oxygen container feature.The PtCu_(3)@PWO_(x)/C exhibits an ultrahigh mass activity(MA)of 3.94 A·mgPt−1 for ORR,which is 26.3 times as high as the commercial Pt/C and the highest value ever reported for PtCu-based binary system.Theoretical calculations reveal that the compressive strain and d-band center downshift of Pt intrinsically contribute to the excellent ORR performance.In H_(2)-air PEMFCs at room temperature,furthermore,the PtCu_(3)@PWO_(x)/C delivers a high power density(218.6 mW·cm^(−2)),much superior to commercial Pt/C(131.6 mW·cm^(−2)).In H_(2)-O_(2) PEMFCs,PtCu_(3)@PWO_(x)/C outputs a maximum power density of 420.1 mW·cm^(−2).This work provides an effective idea for designing oxygen-storing ORR catalysts used for practical room-temperature H_(2)-air fuel cells.
基金This work was supported by the National Natural Science Foundation of China(No.21571038)Education Department of Guizhou Province(No.2021312)+4 种基金Foundation of Guizhou Province(No.2019-5666)State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University,No.2011DA105287-ZR202101)Science Foundation for After graduated Students of Guizhou Province(No.YJSKYJJ2021023)State Key Laboratory of Physical Chemistry of Solid Surfaces(Xiamen University,No.202009)the Open Fund of the Key Lab of Organic Optoelectronics and Molecular Engineering(Tsinghua University).
文摘The construction of efficient and durable electrocatalysts with highly dispersed metal clusters and hydrophilic surface for alkaline hydrogen evolution reaction(HER)remains a great challenge.Herein,we prepared hydrophilic nanocomposites of Ru clusters(~1.30 nm)anchored on Na^(+),K^(+)-decorated porous carbon(Ru/Na^(+),K^(+)-PC)through hydrothermal method and subsequent annealing treatment at 500℃.The Ru/Na^(+),K^(+)-PC exhibits ultralow overpotential of 7 mV at 10 mA·cm^(-2),mass activity of 15.7 A·mgRu^(-1)at 100 mV,and long-term durability of 20,000 cycles potential cycling and 200 h chronopotentiometric measurement with a negligible decrease in activity,much superior to benchmarked commercial Pt/C.Density functional theory based calculations show that the energy barrier of H-OH bond breaking is efficiently reduced due to the presence of Na and K ions,thus favoring the Volmer step.Furthermore,the Ru/Na^(+),K^(+)-PC effectively employs solar energy for obtaining H_(2)in both alkaline water and seawater electrolyzer.This finding provides a new strategy to construct high-performance and cost-effective alkaline HER electrocatalyst.
基金supported by the National Natural Science Foundation of China(No.52403221).
文摘Aqueous zinc-ion batteries(AZIBs)have attracted increasing interest due to their intrinsic safety and low cost,yet their energy density remains limited by the lack of suitable cathode materials.Covalent organic frameworks(COFs),with tunable porosity,structural diversity,and redox-site designability,have emerged as promising AZIBs cathodes.The integration of multiple redox-active sites,such as carbonyl(C=O)and imine(C=N)groups,enables stepwise multi-electron transfer,offering a pathway to higher capacity and voltage output.This review systematically categorizes COFs into n-type,p-type,and bipolar systems based on redox-active moieties and analyzes their charge storage behaviors through cyclic voltammetry(CV).We focus on how the spatial arrangement and electronic nature of C=O/C=N sites influence one-,two-,or three-step electron transfer,as well as Zn2+and H+co-insertion mechanisms.Electrochemical performances,redox kinetics,molecular structure,and electrolyte adaptability are also discussed in detail.By elucidating the structure-mechanism relationships of redox-active COFs,this review highlights molecular design principles that enhance redox-site utilization and energy density.The insights provided herein aim to guide the development of next-generation,high-performance organic cathodes for multi-electron AZIBs.
基金financial support from State Key Laboratory of Coal Mine Disaster Dynamics and Control(2011DA105287-MS202203)Chongqing Human Resources and Social Security Bureau Project(cx2024049)Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0458).
文摘Efficient production of butanediols from biomass-derived feedstocks under mild reaction conditions is still of challenge.Here,we reported a highly efficient Pd-WO_(x) catalyst which was facilely synthesized by a simple‘one pot’solvothermal method for the selective conversion of glucose and lignocellulosic biomass to butanediols with remarkable activity.The optimized process achieved an impressive 56.5%yield of butanediols at 180◦C within 8 h under a low hydrogen pressure of 0.6 MPa,surpassing most reported catalysts.Comprehensive characterization(H_(2)-TPR,XPS,NH3-TPD,etc.)revealed that Pd-WO_(x) not only enhanced H_(2) adsorption and activation but also possessed a higher density of acidic sites to promote selective cleavage of C-C bond in glucose structure,thereby significantly improving the efficiency of sustainable butanediols production.Furthermore,the catalyst demonstrated excellent stability over five reaction cycles.This work provides a viable and efficient strategy for sustainable biomass valorization to produce valuable butanediols.
基金supported by research funding from the National Natural Science Foundation of China(82141130,82372735)the Sichuan Province Science and Technology Support Program(2019YJ0724,2023NSFSC1519)+1 种基金the China Postdoctoral Science Foundation(2022M712240)West China School/Hospital of Stomatology,Sichuan University(RCDWJS2022-10).
文摘Head and neck squamous cell carcinoma(HNSCC)is the sixth most common malignant tumor worldwide.Considering its special anatomical site and the progressive resistance to chemotherapy drugs,the development of more effective,minimally invasive and precise treatment methods is urgently needed.Nanomaterials,given their special properties,can be used as drug carrier systems to improve the therapeutic effect and reduce the adverse effects.The drug carrier systems with photothermal effect can promote the killing of cancer cells and help overcome drug resistance through heat stress.We selected dopamine,a simple raw material,and designed and synthesized three different configurations of nanopolydopamine(nPDA)nanomaterials,including nPDA balls,nPDA plates and porous nPDA balls.In addition to the self-polymerization and self-assembly,nPDA has high photothermal conversion efficiency and can be easily modified.Moreover,we loaded cisplatin into three different configurations of nPDA,creating nPDA-cis(the nano-drug carrier system with cisplatin),and comparatively studied the properties and antitumor effects of all the nPDA and nPDA-cis materials in vitro and nPDA-cis in vivo.We found that the photothermal effect of the nPDA-cis balls drug carrier system had synergistic effect with cisplatin,resulting in excellent antitumor effect and good clinical application prospects.The comparison of the three different configurations of drug carrier systems suggested the importance of optimizing the spatial configuration design and examining the physical and chemical properties in the future development of nano-drug carrier systems.In this study,we also noted the duality and complexity of the influences of heat stress on tumors in vitro and in vivo.The specific mechanisms and the synergy with chemotherapy and immunotherapy will be an important research direction in the future.
基金the National Natural Science Foundation of China(No.21571038)Education Department of Guizhou Province(No.2021312)+4 种基金Foundation of Guizhou Province(No.2019-5666)Science Foundation for Aftergraduated Students of Guizhou Province(No.YJSCXJH2020045)State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University,No.2011DA105287-ZR202101)State Key Laboratory of Physical Chemistry of Solid Surfaces(Xiamen University,No.202009)the Open Fund of the Key Lab of Organic Optoelectronics&Molecular Engineering(Tsinghua University)。
文摘Developing highly stable and active non-Pt oxygen reduction reaction(ORR)electrocatalysts for power generation device raises great concerns and remains a challenge.Here,we report novel truncated Pd tetrahedrons(T-Pd-Ths)enclosed by{111}facets with excellent uniformity,which have both low-coordinated surface sites and distinct lattice distortions that would induce“local strain”.In alkaline electrolyte,the T-Pd-Ths/C achieves remarkable ORR specific/mass activity(SA/MA)of 2.46 mA·cm^(−2)/1.69 A·mgPd^(−1),which is 12.3/16.9 and 10.7/14.1 times higher than commercial Pd/C and Pt/C,respectively.The T-Pd-Ths/C also exhibits high in-situ carbon monoxide(CO)tolerance and 50,000 cycles durability with an activity loss of 7.69%and morphological stability.The rotating ring-disk electrode(RRDE)measurements show that a 4-electron process occurs on T-PdThs/C.Theoretical calculations demonstrate that the low-coordinated surface sites contribute largely to the enhancement of ORR activity.In actual direct methanol fuel cell(DMFC)device,the T-Pd-Ths/C delivers superior open-circuit voltage(OCV)and peak power density(PPD)to commercial Pt/C from 25 to 80℃,and the maximum PPD can reach up to 163.7 mW·cm−2.This study demonstrates that the T-Pd-Ths/C holds promise as alternatives to Pt for ORR in DMFC device.
基金the National Natural Science Foundation of China(Nos.52102188 and 52072337)the Key Research and Development Program of Zhejiang Province(No.2021C01030)+4 种基金the Natural Science Foundation of Zhejiang Province(No.LQ21F040005)the Postdoctoral Science Foundation of Zhejiang Province(No.ZJ2022132)the Science and Technology Project of Wenzhou(No.2022G0253)the Leading Talent Entrepreneurship Project of Ouhai District,Wenzhou City,the Young Elite Scientists Sponsorship Program by CAST(No.YESS20210444)the Shanxi‐Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SZ‐TD004).
文摘Halide perovskite light emitting diodes(LEDs)have gained great progress in recent years.However,mixed-halide perovskites for blue LEDs usually suffer from electroluminescence(EL)spectra shift at a high applied voltage or current density,limiting their efficiency.In this work,we report a strategy of using single-layer perovskite quantum dots(QDs)film to tackle the electroluminescence spectra shift in pure-blue perovskite LEDs and improve the LED efficiency by co-doping copper and potassium in the mixed-halide perovskite QDs.As a result,we obtained pure-blue halide perovskite QD-LEDs with stable EL spectra centred at 469 nm even at a current density of 1,617 mA·cm^(−2).The optimal device presents a maximum external quantum efficiency(EQE)of 2.0%.The average maximum EQE and luminance of the LEDs are 1.49%and 393 cd·m^(−2),increasing 62%and 66%compared with the control LEDs.Our study provides an effective strategy for achieving spectra-stable and highly efficient pure-blue perovskite LEDs.
文摘The large-scale preparation ofmonolayer two-dimensional(2D)material remains a great challenge,which hinders its real-world applications.Herein,we report a novel layered metal–organic framework(MOF),IPM-1,whichwas synthesized froma cage-like organic linker,with extremely weak interlaminar interaction.When subjected to external disturbance,IPM-1 degenerated into an intermediate state between the crystalline and amorphous phase,in which the layers retain the inplane two-dimensional periodic structure but aremisaligned in the third dimension,leading to the loss of apparent porosity and crystallinity.This amorphous IPM-1 is readily exfoliated at gramscale into crystalline 2D nanosheets with a thickness of 1.15 nm,excellent thickness homogeneity,lateral size up to 10μm,and restored microporosity.IPM-1 nanosheets exhibit high chemical stability and catalytic activity in the oxidation of alcohol,combining the advantages of both homogeneous and heterogeneous catalyst.This work underscores that MOFs without apparent crystallinity can be ideal precursors for the successful preparation of 2D crystalline monolayer nanosheets.
基金supported by the National Natural Science Foundation of China(No.21571038)Foundation of Guizhou Province(No.2019-5666)+3 种基金Education Department of Guizhou Province(No.2021312)State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University,No.2011DA105287-ZR202101)the Open Fund of the Key Lab of Organic Optoelectronics&Molecular Engineering(Tsinghua University)State Key Laboratory of Physical Chemistry of Solid Surfaces(No.202009).
文摘The development of cathode oxygen reduction reaction(ORR)catalysts with high characteristics for practical,direct methanol fuel cells(DMFCs)has continuously increased the attention of researchers.In this work,interface-rich Au-doped PdBi(PdBiAu)branched one-dimensional(1D)alloyed nanochains assembled by sub-6.5 nm particles have been prepared,exhibiting an ORR mass activity(MA)of 6.40 A·mgPd^(−1) and long-term durability of 5,000 cycles in an alkaline medium.The MA of PdBiAu nanochains is 46 times and 80 times higher than that of commercial Pt/C(0.14 A·mgPt^(−1))and Pd/C(0.08 A·mgPd^(−1)).The MA of binary PdBi nanochains also reaches 5.71 A·mgPd^(−1).Notably,the PdBiAu nanochains exhibit high in-situ carbon monoxide poisoning resistance and high methanol tolerance.In actual DMFC device tests,the PdBiAu nanochains enhance power density of 140.1 mW·cm^(−2)(in O_(2))/112.4 mW·cm^(−2)(in air)and durability compared with PdBi nanochains and Pt/C.The analysis of the structure–function relationship indicates that the enhanced performance of PdBiAu nanochains is attributed to integrated functions of surficial defect-rich 1D chain structure,improved charge transfer capability,downshift of the d-band center of Pd,as well as the synergistic effect derived from“Pd-Bi”and/or“Pd-Au”dual active sites.
基金financial support by the National Natural Science Foundation of China(grant nos.22201247 and 22105028)startup funding from Zhejiang University and Natural Science Foundation of Chongqing(cstc2021jcyj-msxmX0572)+1 种基金the National Facility for Protein Science in Shanghai(NFPS),Shanghai Advanced Research Institute,Chinese Academy of Sciences,for providing technical support in X-ray diffraction data collection and analysis(grant no.2023-NFPS-PT-500479)We thank the Chemistry Instrumentation Center Zhejiang University for the technical support.
文摘A challenge facing scientists is the rational synthesis of highly crystalline covalent organic frameworks(COFs),consisting of both n-type and p-type redox-active units,as cathodes for high-performance lithium-ion batteries(LIBs).Herein,we apply reticular chemistry to regulate a COF platform with the kgm topology via an in-situ postsynthetic oxidation strategy.We integrate both n-type and p-type redox-active units into a resulting COF skeleton—TPDA-DQTA-COF,and this COF-based cathode shows an enhanced performance for LIBs compared to the parent TPDA-DMTA-COF.On account of dual redox-active units for PF6−/Li+costorage,the TPDADQTA-COF cathode presents the highly reversible capacity of 308 mAh g−1 at 0.2 A g^(−1) and the high energy density of 800 Wh kg^(−1).The long-term cycling experiment reveals a capacity retention of 91%after 200 cycles at a low current density of 0.5 A g^(−1).The combined Fourier transform infrared and X-ray photoelectron spectroscopy experiments suggest that the in-situ electrochemical oxidation from the C-OH to the C=O group of COFs occurs during the charging process.We believe our study demonstrates that the atomic-level modification of functional groups in COF-based cathode materials has a significant impact on the macroscopic performance of lithium-ion storage,clearly illustrating the structure-property relationship.
