Taking the underground shale of the Silurian Longmaxi Formation in southern Sichuan Basin as the research object,stress-sensitive experiments on self-supporting fractures and micro-visualization experiments on gas-wat...Taking the underground shale of the Silurian Longmaxi Formation in southern Sichuan Basin as the research object,stress-sensitive experiments on self-supporting fractures and micro-visualization experiments on gas-water flow were conducted under simulated reservoir conditions to study the mechanism of microscopic gas-water flow during the fracture closure process and discuss its engineering applications.The results show that as the effective stress gradually increased from 5 MPa to 60 MPa with an increment of 5 MPa per step,the self-supporting fracture closure exhibited a two-stage characteristic of being fast in the early stage and slow in the later stage,with the inflection point stress ranging from 32 MPa to 35 MPa,and the closure degree of 47%-76%.The effective stress increase gradually rose from 5 MPa per step to 20 MPa per step,and the early fracture closure accelerated,with the maximum closure degree increasing by 8.6%.As the fracture width decreased from 500μm to 50μm,the gas-phase shifted from continuous to discontinuous flow,and the proportion of the critical gas-phase flow to maintain the continuous gas-phase flow increased.In the early stage of fracture closure(fracture width greater than 300μm),the continuous gas-phase flow is controlled by the fracture width-the larger the fracture width,the smaller the proportion of the critical gas-phase flow to maintain the continuous gas-phase flow.In the late stage of fracture closure(fracture width less than 300μm),as the fractures continue to close,the dominant role of the surface roughness of the fractures becomes stronger,and the proportion of the critical gas-phase flow to maintain the continuous gas-phase flow exceeds 70%.A reasonable pressure control during stable production and pressure reduction in the early stage(the peak pressure drop at the wellhead is less than 32 MPa)to delay the self-supporting fracture closure is conducive to the stable and increased production of gas wells.展开更多
Direct seawater electrolysis is a promising way for hydrogen energy production.However,developing efficient and cost-effective electrocatalysts remains a significant challenge for seawater electrolysis with industrial...Direct seawater electrolysis is a promising way for hydrogen energy production.However,developing efficient and cost-effective electrocatalysts remains a significant challenge for seawater electrolysis with industrial-level current density due to high concentration of salts and compete reaction of chlorine evolution.Herein,a 1D NiFe_(2)O_(4)/NiMoO_(4) heterostructure as a bifunctional electrocatalyst for overall seawater splitting is constructed by combining NiMoO_(4) nanowires with NiFe_(2)O_(4)nanoparticles on carbon felt(CF)by a simple hydrothermal,impregnation and calcination method.The electrocatalyst exhibits low overpotential of 237 and 292 mV for oxygen evolution reaction and hydrogen evolution reaction at 400 m A/cm^(2)in the alkaline seawater(1 mol/L KOH+0.5 mol/L NaCl)due to the plentiful interfaces of NiFe_(2)O_(4)/NiMoO_4 which exposes more active sites and expands the active surface area,thereby enhancing its intrinsic activity and promoting the reaction kinetics.Notably,it displays low voltages of 1.95 V to drive current density of 400 m A/cm^(2)in alkaline seawater with its excellent stability of 200 h at above 100 m A/cm^(2),exhibiting outstanding performance and good corrosion resistance.This work provides an effective strategy for constructing efficient and cost-effective electrocatalysts for industrial seawater electrolysis,underscoring its potential for sustainable energy applications.展开更多
High/medium entropy alloys(HEAs/MEAs)with high electrocatalytic activity have attracted great attention in water electrolysis applications.However,facile synthesis of self-supporting high/medium entropy alloys electro...High/medium entropy alloys(HEAs/MEAs)with high electrocatalytic activity have attracted great attention in water electrolysis applications.However,facile synthesis of self-supporting high/medium entropy alloys electrocatalysts with rich active sites through classical metallurgical methods is still a challenge.Here,a self-supporting porous FeCoNi MEA electrocatalyst with nanosheets-shaped surface for oxygen evolution reaction(OER)was prepared by a one-step electrochemical process from the metal oxides in molten CaCl_(2).The formation of the FeCoNi MEA is attributed to the oxides electro-reduction,high-temperature diffusion and solid solution.Additionally,the morphology and structure of the FeCoNi MEA can be precisely controlled by adjusting the electrolysis time and temperature.The electronic structure regulation and the reduced energy barrier of OER from the“cocktail effect”,the abundant exposed active sites brought by surface ultrathin nanosheets,the good electronic conductivity and electrochemical stability from the self-supporting structure enable the FeCoNi MEA electrode shows high-performance OER electrocatalysis,exhibiting a low overpotential of 233 mV at a current density of 10 mA cm^(-2),a low Tafel slope of 29.8 mV dec^(-1),and an excellent stability for over 500 h without any obvious structural destruction.This work demonstrates a facile one-step electrochemical metallurgical approach for fabricating self-supporting HEAs/MEAs electrocatalysts with nanosized surface for the application in water electrolysis.展开更多
Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiF...Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure as bifunctional electrocatalyst was constructed based on porous Ni-Fe electrodeposition on three-dimensional(3D)carbon fiber cloth,in situ oxidation,and chemical sulfuration.Results showed that the Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure with a large specific surface area exhibits good bifunctional activity and stability for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)because of the abundance of active sites,synergistic effect of the heterostructure,superhydrophilic surface,and stable,self-supporting structure.The results further confirmed that the Ni_(x)Fe-S phase in the heterostructure is transformed into metal oxides/hydroxides and Ni_(3)S_(2) during OER.Compared with the commercial 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer,the self-supporting Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) electrolyzer exhibits better stability and lower cell voltage in the fluctu-ating current density range of 10-500 mA/cm^(2).Particularly,the cell voltage of Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) is only approximately 3.91 V at an industrial current density of 500 mA/cm^(2),which is lower than that of the 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer(i.e.,approximately 4.79 V).This work provides a promising strategy to develop excellent bifunctional electrocatalysts for fluctuating overall water splitting.展开更多
A flexible air electrode with excellent activity and stability is essential for flexible zinc-air batteries.In this study,we report the rational design of nitrogen-doped carbon nanotube-encapsulated Co9S8 nanopar-ticl...A flexible air electrode with excellent activity and stability is essential for flexible zinc-air batteries.In this study,we report the rational design of nitrogen-doped carbon nanotube-encapsulated Co9S8 nanopar-ticles on carbon cloth(Co9S8/NCNTs/CC),serving as self-supporting air electrodes for both liquid-state and flexible zinc-air batteries.The Co9S8/NCNTs/CC-1 exhibited a half-wave potential of 0.86 V for oxygen re-duction reaction(ORR)and achieved a current density of 10 mA cm-2 for oxygen evolution reaction(OER)at a voltage of only 1.52 V.The well-constructed nanotube on carbon cloth facilitates mass diffu-sion and electron transfer,while enhancing the mechanical flexibility of the material.Density functional theory(DFT)calculations suggested that the synergistic interaction between Co9S8 and NCNTs effectively enhanced the bifunctional electrocatalytic performance of the material.Liquid-state and flexible zinc-air batteries assembled with Co9S8/NCNTs/CC-1 demonstrated outstanding charge-discharge capabilities and long-term stability.展开更多
Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements hav...Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.展开更多
The design and fabrication of ordered epitaxial MOF-on-MOF heterostructures as highly efficient electrocatalysts for water splitting is crucial but still challenging.In this study,a simple coordination-driven self-ass...The design and fabrication of ordered epitaxial MOF-on-MOF heterostructures as highly efficient electrocatalysts for water splitting is crucial but still challenging.In this study,a simple coordination-driven self-assembly method is used to fabricate controllable MOF-on-MOF multiscale heterostructures,where triangular host MOF(ZIF-67)nanosheets undergo in situ epitaxial growth to form uniform orthogonal vip MOF(CoFe PBA)nanosheets.Phosphorus(P)is further introduced in situ to fabricate CoP and Fe_(2)P heterostructured nanosheets(CoFe-P-NS),which exhibit excellent bifunctional electrocatalytic performance due to the enhancement of intrinsic electrocatalytic activity by p-d orbital hybridization.Specifically,the CoFe-P-NS requires low overpotential of 259 and 307 mV to reach 500 mA cm−2 for HER and OER,respectively.Remarkably,the assembled electrolysis cell maintained a large current density of 300 mA cm−2 for over 360 h with negligible voltage increase during alkaline seawater electrolysis.Experiments and theoretical calculations show that the synergistic catalytic activity of bimetallic phosphides arises from p-d orbital hybridization,where the CoP-P sites enhance HER by optimizing H*adsorption in the Volmer-Heyrovsky steps,while the Fe_(2)P-Fe sites accelerate OER by lowering the energy barrier of the rate-determining step from O*to OOH*.This study provides valuable insights into the design of a controllable MOF-on-MOF-based electrocatalyst toward alkaline seawater splitting.展开更多
Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt...Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt-based electrocatalysts,emphasizing their structural engineering for enhanced the performance of electrocatalytic nitrate reduction reaction(NO3RR)through dimensional control,compositional tuning,and coordination microenvironment modulation.Notably,by critically analyzing metallic cobalt,cobalt alloys,cobalt compounds,cobalt single atom and molecular catalyst configurations,we firstly establish correlations between atomic-scale structural features and catalytic performance in a coordination environment perspective for NO3RR,including the dynamic reconstruction during operation and its impact on active site.Synergizing experimental breakthroughs with computational modeling,we decode mechanisms underlying competitive hydrogen evolution suppression,intermediate adsorption-energy optimization,and durability enhancement in complex aqueous environments.The development of cobalt-based catalysts was summarized and prospected,and the emerging opportunities of machine learning in accelerating the research and development of high-performance catalysts and the configuration of series reactors for scalable nitrate-to-ammonia systems were also introduced.Bridging surface science and applications,it outlines a framework for designing multifunctional electrocatalysts to restore nitrogen cycle balance sustainably.展开更多
Structural engineering of Pt-based nanoalloys is crucial for the rational design and manufacturing of high-performance and low-cost electrocatalysts for hydrogen evolution reaction(HER).Here,we reported PtNi nanoparti...Structural engineering of Pt-based nanoalloys is crucial for the rational design and manufacturing of high-performance and low-cost electrocatalysts for hydrogen evolution reaction(HER).Here,we reported PtNi nanoparticles with a refined size of 2.71 nm and regular strains loaded on carbon black,synthesized using the high-temperature liquid shock(HTLS)method.This approach offers significant advantages over conventional synthesis methods,including high scalability,rapid reaction rates,and precise control over the size and shape of nanocrystals.Importantly,the synthesized PtNi electrocatalysts demonstrate outstanding catalytic activity and long-term stability for HER,achieving low overpotentials of 19 and 203 mV at current densities of 10 and 1000 mA/cm^(2),respectively.The superior performance can be attributed to the combination of a refined particle size,lattice strains,and synergistic effects between Pt and Ni.This rapid liquid-state synthesis demonstrated here holds great potential for scalable and industrial manufacturing of micro-/nano-catalysts.展开更多
Silica nanoparticles-stabilized cobalt and nitrogen-doped carbon materials were synthesized through pyrolysis of metal-organic-framework of ZIF-67 supported by silica nanoparticles.The experimental results reveal that...Silica nanoparticles-stabilized cobalt and nitrogen-doped carbon materials were synthesized through pyrolysis of metal-organic-framework of ZIF-67 supported by silica nanoparticles.The experimental results reveal that the introduction of the silica nanoparticles can stabilize the microstructure of the derived CoN-C materials,which in turn exhibits the promising electrocatalytic activity towards both oxygen reduction and oxygen evolution reactions.The optimized sample exhibits a better oxygen reduction activity than commercial Pt/C catalyst as confirmed by the positive shift of half-wave potential by 20 mV while it has a low overpotential of 273 mV for oxygen evolution reactions with the retained performance over 80%after 25,000 s of continuous operation.It is demonstrated that the introduction of support frame might be an effective way to improve the activity and stability of metal-organic-framework derived electrocatalyst with stabilized microstructure.展开更多
Rational design of non-noble electrocatalysts with high performance for oxygen evolution reaction(OER)still remains a challenge.In this study,a ZIF-derived electrocatalyst(Co@Fe-P)with a core-shell structure is design...Rational design of non-noble electrocatalysts with high performance for oxygen evolution reaction(OER)still remains a challenge.In this study,a ZIF-derived electrocatalyst(Co@Fe-P)with a core-shell structure is designed by using Co-compounds as the core and PO_(4)^(3-)decorated Fe-compounds as the shell.The inner Co-core and outer Fe-shell are connected through Co-O-Fe and Fe-O-P linkage.The Co@Fe-P electrocatalyst exhibits an enhanced performance for OER with a low overpotential(280 mV),low Tafel slope(41.9 mV dec^(-1))at 10 mA cm^(-2),and a 60-h durability.The electron transfer from the CoOOH-core to the FeOOH-shell is greatly facilitated,which improves the OER activity of Co@Fe-P kinetically.Theoretical calculations indicate that the interaction of Co-O-Fe and Fe-O-P in Co@Fe-P reduces the overlap between the O 2p and Fe 3d orbitals,which greatly facilitates the transformation from*OH to*O during the OER process via the adsorbate evolution mechanism(AEM)pathway.This finding provides insight for the design of efficient electrocatalysts for OER.展开更多
Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen ba...Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.展开更多
Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improv...Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.展开更多
Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the key reactions in numerous renewable energy devices. Unlike conventional powdered catalysts, self-supported catalysts are extensively employed i...Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the key reactions in numerous renewable energy devices. Unlike conventional powdered catalysts, self-supported catalysts are extensively employed in oxygen electrocatalysis because of the enhanced electron-transfer rate, high specific surface area, and superior mechanical flexibility. Among the self-supported conductive substrates, carbon fiber usually exhibits several distinctive advantages, such as a straightforward preparation process, relatively low cost, good stability, and excellent conductivity. Against this background,carbon fiber-based self-supported electrocatalysts have been widely applied and studied in oxygen electrocatalysis, indicating a promising development direction in oxygen electrocatalyst research.Thus, it is essential to offer an overall summary of the research progress in this field to facilitate its subsequent development. Taking the regulatory mechanisms and modification methods as a starting point, this review comprehensively summarizes recent research on carbon fiber-based self-supported electrocatalysts in recent years. Firstly, a brief overview of the synthesis methods and regulatory mechanisms of carbon fiber-based self-supported electrocatalysts is given. Furthermore, the view also highlights the modification methods and research progress of self-supported electrocatalysts synthesized on carbon fiber-based substrates in recent years in terms of different dopant atoms. Finally, the prospects for the application of self-supported electrocatalysts based on carbon fiber in oxygen electrocatalysis and the possible future directions of their development are presented. This review summarizes recent developments and applications of self-supported bi-functional electrocatalysts with carbon fiber-based materials as the conducting substrate in oxygen electrocatalysis. It also lays a robust scientific foundation for the subsequent reasonable design of highly effective carbon fiber-based self-supported electrocatalysts.展开更多
The flexible self-supporting electrode can maintain good mechanical and electrical properties while retaining high specific capacity,which meets the requirements of flexible batteries.Lithium-sulfur batteries(LSBs),as...The flexible self-supporting electrode can maintain good mechanical and electrical properties while retaining high specific capacity,which meets the requirements of flexible batteries.Lithium-sulfur batteries(LSBs),as a new generation of energy storage system,hold much higher theoretical energy density than traditional batteries,and they have attracted extensive attention from both the academic and industrial communities.Selection of a proper substrate material is important for the flexible self-supporting electrode.Carbon materials,with the advantages of light weight,high conductivity,strong structural plasticity,and low cost,provide the electrode with a large loading space for the active material and a conductive network.This makes the carbon materials meet the mechanical and electrochemical requirements of flexible electrodes.In this paper,the commonly used fabrication methods and recent research progresses of the flexible self-supporting cathode with a carbon material as the substrate are introduced.Various sulfur loading methods are summarized,which provides useful information for the structural design of the cathode.As the first review article of the carbon-based flexible self-supporting LSB cathodes,it provides valuable guidance for the researchers working in the field of LSB.展开更多
Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.The oxygen evolution reaction(OER)is considered as the bottleneck reaction in an overall ...Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.The oxygen evolution reaction(OER)is considered as the bottleneck reaction in an overall water splitting system because it involves 4e- and 4H+ transfer processes.Currently,it is highly desirable to explore low-cost alternative catalysts for OER at ambient conditions.Herein,we report for the first time that nickel phosphide(Ni2P)nanosheets can be facilely grown on Fe foam(FF)as an efficient electrocatalyst for OER with excellent durability and catalytic activity under alkaline conditions.To reach a current density of 10 m A/cm2,the Ni2P-FF catalyst required a low overpotential of only 198 mV for OER.The catalyst’s high OER activity and durability were well maintained at a high current density.The required overpotentials were only 267 and 313 mV to achieve the current densities of 100 and 300 m A/cm2,respectively.The combination of low-cost Fe foam with Ni2P provides a promising low-cost catalyst for large-scale application of electrocatalytic water splitting.展开更多
Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x)integrated electrode for w...Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x)integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2)under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2)under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2)for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2)at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.展开更多
The integration of topology optimization(TO)and additive manufacturing(AM)technologies can create significant synergy benefits,while the lack of AM-friendly TO algorithms is a serious bottleneck for the application of...The integration of topology optimization(TO)and additive manufacturing(AM)technologies can create significant synergy benefits,while the lack of AM-friendly TO algorithms is a serious bottleneck for the application of TO in AM.In this paper,a TO method is proposed to design self-supporting structures with an explicit continuous self-supporting constraint,which can be adaptively activated and tightened during the optimization procedure.The TO procedure is suitable for various critical overhang angles(COA),which is integrated with build direction assignment to reduce performance loss.Besides,a triangular directional self-supporting constraint sensitivity filter is devised to promote the downward evolution of structures and maintain stability.Two numerical examples are presented;all the test cases have successfully converged and the optimized solutions demonstrate good manufacturability.In the meanwhile,a fully self-supporting design can be obtained with a slight cost in performance through combination with build direction assignment.展开更多
Hard carbon stands out as the most promising candidate for anodes in sodium-ion battery.Nevertheless,addressing the challenges of low initial Coulombic efficiency and rate performance is crucial for practical applicat...Hard carbon stands out as the most promising candidate for anodes in sodium-ion battery.Nevertheless,addressing the challenges of low initial Coulombic efficiency and rate performance is crucial for practical applications.In this study,we employed a dimensionally designed approach,using six different biomass precursors,to preserve their inherent fine hierarchical morphological structures and appearances during the synthesis of selfsupporting carbon materials.Benefiting from its low-tortuosity structure that facilitates electron and ion transport,as well as its surface-enriched C=O functional groups and significant closed micropore areas,the obtained carbon material exhibits excellent electrochemical performance in sodium-ion storage,demonstrated by finite element simulation.Notably,the carbonized basswood exhibited a remarkable initial Coulombic efficiency of up to 92.4%and demonstrated outstanding rate performance,achieving a capacity of 223.3 mAh·g^(-1)at a high current density of2 A·g^(-1).In addition,thorough investigation was conducted on the influence of microstructure on the sodium storage behavior of hard carbon.Ex situ X-ray diffraction(XRD)was used to confirm that the capacity in the plateau region originates from interlayer insertion and closed-pore filling,which is consistent with the results obtained from smallangle X-ray scattering.These findings underscore the immense potential of leveraging surface functionalization and structural design to bolster the performance of hard carbon,paving the way for promising future advancements in this field.展开更多
Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water s...Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water separation.Herein,we report a versatile approach to fabricate surface carbonized membranes with self-standing property from biomass-derived precursor by synergistic charring of phytic acid,arginine and filter paper.The obtained membrane exhibited superhydrophobicity in oil,excellent fouling resistance,and self-supporting ability.The membrane can be cycle-used at least 12 times with high permeation flux(up to 1380 L·m^(-2)·h^(-1))and separation efficiency(up to 99.4%).展开更多
基金Supported by the National Science and Technology Major Project of New-Type Oil and Gas Exploration and Development(2025ZD14041)National Science and Technology Major Project of China(2025ZD14053)+2 种基金Science and Technology Project of CNPC(2023ZZ21)Youth Science and Technology Project of CNPC(2024DQ03241)Postdoctoral Research Project of PetroChina Southwest Oil and Gas Field Company(20230304-13)。
文摘Taking the underground shale of the Silurian Longmaxi Formation in southern Sichuan Basin as the research object,stress-sensitive experiments on self-supporting fractures and micro-visualization experiments on gas-water flow were conducted under simulated reservoir conditions to study the mechanism of microscopic gas-water flow during the fracture closure process and discuss its engineering applications.The results show that as the effective stress gradually increased from 5 MPa to 60 MPa with an increment of 5 MPa per step,the self-supporting fracture closure exhibited a two-stage characteristic of being fast in the early stage and slow in the later stage,with the inflection point stress ranging from 32 MPa to 35 MPa,and the closure degree of 47%-76%.The effective stress increase gradually rose from 5 MPa per step to 20 MPa per step,and the early fracture closure accelerated,with the maximum closure degree increasing by 8.6%.As the fracture width decreased from 500μm to 50μm,the gas-phase shifted from continuous to discontinuous flow,and the proportion of the critical gas-phase flow to maintain the continuous gas-phase flow increased.In the early stage of fracture closure(fracture width greater than 300μm),the continuous gas-phase flow is controlled by the fracture width-the larger the fracture width,the smaller the proportion of the critical gas-phase flow to maintain the continuous gas-phase flow.In the late stage of fracture closure(fracture width less than 300μm),as the fractures continue to close,the dominant role of the surface roughness of the fractures becomes stronger,and the proportion of the critical gas-phase flow to maintain the continuous gas-phase flow exceeds 70%.A reasonable pressure control during stable production and pressure reduction in the early stage(the peak pressure drop at the wellhead is less than 32 MPa)to delay the self-supporting fracture closure is conducive to the stable and increased production of gas wells.
基金supported by the National Natural Science Foundation of China(No.51908408)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2019KJ008)Basic Research Program of Jiangsu Province(No.BK20241845)。
文摘Direct seawater electrolysis is a promising way for hydrogen energy production.However,developing efficient and cost-effective electrocatalysts remains a significant challenge for seawater electrolysis with industrial-level current density due to high concentration of salts and compete reaction of chlorine evolution.Herein,a 1D NiFe_(2)O_(4)/NiMoO_(4) heterostructure as a bifunctional electrocatalyst for overall seawater splitting is constructed by combining NiMoO_(4) nanowires with NiFe_(2)O_(4)nanoparticles on carbon felt(CF)by a simple hydrothermal,impregnation and calcination method.The electrocatalyst exhibits low overpotential of 237 and 292 mV for oxygen evolution reaction and hydrogen evolution reaction at 400 m A/cm^(2)in the alkaline seawater(1 mol/L KOH+0.5 mol/L NaCl)due to the plentiful interfaces of NiFe_(2)O_(4)/NiMoO_4 which exposes more active sites and expands the active surface area,thereby enhancing its intrinsic activity and promoting the reaction kinetics.Notably,it displays low voltages of 1.95 V to drive current density of 400 m A/cm^(2)in alkaline seawater with its excellent stability of 200 h at above 100 m A/cm^(2),exhibiting outstanding performance and good corrosion resistance.This work provides an effective strategy for constructing efficient and cost-effective electrocatalysts for industrial seawater electrolysis,underscoring its potential for sustainable energy applications.
基金supported by the National Natural Science Foundation of China(Nos.52022054,51974181,52004155,52004157,52374307,52304331,52334009)the National Key Research and Development Program of China(No.2022YFC2906100)+4 种基金the China Postdoctoral Science Foundation(No.2022M712023)the Science and Technology Commission of Shanghai Municipality(No.21DZ1208900)the Innovation Program of Shanghai Municipal Education Commission(No.2023ZKZD48)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(No.TP2019041)the“Shuguang Program”supported by the Shanghai Education Development Foundation and the Shanghai Municipal Education Commission(No.21SG42).
文摘High/medium entropy alloys(HEAs/MEAs)with high electrocatalytic activity have attracted great attention in water electrolysis applications.However,facile synthesis of self-supporting high/medium entropy alloys electrocatalysts with rich active sites through classical metallurgical methods is still a challenge.Here,a self-supporting porous FeCoNi MEA electrocatalyst with nanosheets-shaped surface for oxygen evolution reaction(OER)was prepared by a one-step electrochemical process from the metal oxides in molten CaCl_(2).The formation of the FeCoNi MEA is attributed to the oxides electro-reduction,high-temperature diffusion and solid solution.Additionally,the morphology and structure of the FeCoNi MEA can be precisely controlled by adjusting the electrolysis time and temperature.The electronic structure regulation and the reduced energy barrier of OER from the“cocktail effect”,the abundant exposed active sites brought by surface ultrathin nanosheets,the good electronic conductivity and electrochemical stability from the self-supporting structure enable the FeCoNi MEA electrode shows high-performance OER electrocatalysis,exhibiting a low overpotential of 233 mV at a current density of 10 mA cm^(-2),a low Tafel slope of 29.8 mV dec^(-1),and an excellent stability for over 500 h without any obvious structural destruction.This work demonstrates a facile one-step electrochemical metallurgical approach for fabricating self-supporting HEAs/MEAs electrocatalysts with nanosized surface for the application in water electrolysis.
基金financially supported by the National Natural Science Foundation of China (Nos. 51874020 and 52004022)
文摘Stable non-noble metal bifunctional electrocatalysts are one of the challenges to the fluctuating overall water splitting driven by re-newable energy.Herein,a novel self-supporting hierarchically porous Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure as bifunctional electrocatalyst was constructed based on porous Ni-Fe electrodeposition on three-dimensional(3D)carbon fiber cloth,in situ oxidation,and chemical sulfuration.Results showed that the Ni_(x)Fe-S/NiFe_(2)O_(4) heterostructure with a large specific surface area exhibits good bifunctional activity and stability for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)because of the abundance of active sites,synergistic effect of the heterostructure,superhydrophilic surface,and stable,self-supporting structure.The results further confirmed that the Ni_(x)Fe-S phase in the heterostructure is transformed into metal oxides/hydroxides and Ni_(3)S_(2) during OER.Compared with the commercial 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer,the self-supporting Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) electrolyzer exhibits better stability and lower cell voltage in the fluctu-ating current density range of 10-500 mA/cm^(2).Particularly,the cell voltage of Ni1/5Fe-S/NiFe_(2)O_(4)||Ni1/2Fe-S/NiFe_(2)O_(4) is only approximately 3.91 V at an industrial current density of 500 mA/cm^(2),which is lower than that of the 20wt%Pt/C||IrO_(2)-Ta_(2)O_(5) electrolyzer(i.e.,approximately 4.79 V).This work provides a promising strategy to develop excellent bifunctional electrocatalysts for fluctuating overall water splitting.
基金supported by the Natural Sci-ence Foundation of Xinjiang Uygur Autonomous Region(Nos.2022D01E36 and 2022D01E38)the National Natural Science Foun-dation of China(Nos.22369016 and 22065034)the Outstand-ing Doctoral Student Innovation Project of Xinjiang University(No.XJU2024BS055).
文摘A flexible air electrode with excellent activity and stability is essential for flexible zinc-air batteries.In this study,we report the rational design of nitrogen-doped carbon nanotube-encapsulated Co9S8 nanopar-ticles on carbon cloth(Co9S8/NCNTs/CC),serving as self-supporting air electrodes for both liquid-state and flexible zinc-air batteries.The Co9S8/NCNTs/CC-1 exhibited a half-wave potential of 0.86 V for oxygen re-duction reaction(ORR)and achieved a current density of 10 mA cm-2 for oxygen evolution reaction(OER)at a voltage of only 1.52 V.The well-constructed nanotube on carbon cloth facilitates mass diffu-sion and electron transfer,while enhancing the mechanical flexibility of the material.Density functional theory(DFT)calculations suggested that the synergistic interaction between Co9S8 and NCNTs effectively enhanced the bifunctional electrocatalytic performance of the material.Liquid-state and flexible zinc-air batteries assembled with Co9S8/NCNTs/CC-1 demonstrated outstanding charge-discharge capabilities and long-term stability.
基金financially supported by the National Natural Science Foundation of China (22350410386,W2412116,22375200,U22A202175,21961142006)。
文摘Exploring cost-effective and efficient catalysts for oxygen reduction reaction(ORR)poses a significant challenge,espe-cially in the pursuit of alternatives to precious metals like platinum.Significant advancements have driven electrochem-ists to develop efficient ORR catalysts using abundant materials,particularly iron(Fe)-based,known for their exceptional performance in ORR.While the crucial function of Fe in boosting ORR catalytic activity is recognized,the connection between material attributes and catalytic performance remains enigmatic.Understanding the dynamic processes involved in oxygen electrocatalysis is paramount for designing precious-metals-free ORR electrocatalysts.Mössbauer spectroscopy stands out as a powerful technique for deciphering the structural characteristics of Fe species in catalysis,facilitating the identification of active sites and the clarification of catalytic mechanisms.By showcasing noteworthy case studies within this review,we demonstrate the application of in-situ/operando 57Fe Mössbauer spectroscopy across diverse Fe-involved materials in ORR catalysis.This sheds light on various aspects of ORR catalysis,such as identifying active sites,assessing stability,and understanding the reaction mechanism.Our inquiry drives towards the opportunities and hurdles associ-ated with Mössbauer spectroscopy,unveiling potential breakthroughs and avenues for enhancement within this pivotal research realm.
基金financial support of the National Natural Science Foundation of China (21875247,21072221, 21172252)the Project of Talent Cultivation for Carbon Peak and Carbon Neutrality of the University of Chinese of Academy of Science
文摘The design and fabrication of ordered epitaxial MOF-on-MOF heterostructures as highly efficient electrocatalysts for water splitting is crucial but still challenging.In this study,a simple coordination-driven self-assembly method is used to fabricate controllable MOF-on-MOF multiscale heterostructures,where triangular host MOF(ZIF-67)nanosheets undergo in situ epitaxial growth to form uniform orthogonal vip MOF(CoFe PBA)nanosheets.Phosphorus(P)is further introduced in situ to fabricate CoP and Fe_(2)P heterostructured nanosheets(CoFe-P-NS),which exhibit excellent bifunctional electrocatalytic performance due to the enhancement of intrinsic electrocatalytic activity by p-d orbital hybridization.Specifically,the CoFe-P-NS requires low overpotential of 259 and 307 mV to reach 500 mA cm−2 for HER and OER,respectively.Remarkably,the assembled electrolysis cell maintained a large current density of 300 mA cm−2 for over 360 h with negligible voltage increase during alkaline seawater electrolysis.Experiments and theoretical calculations show that the synergistic catalytic activity of bimetallic phosphides arises from p-d orbital hybridization,where the CoP-P sites enhance HER by optimizing H*adsorption in the Volmer-Heyrovsky steps,while the Fe_(2)P-Fe sites accelerate OER by lowering the energy barrier of the rate-determining step from O*to OOH*.This study provides valuable insights into the design of a controllable MOF-on-MOF-based electrocatalyst toward alkaline seawater splitting.
基金supported by the National Natural Science Foundation of China(Grant Nos.:21825201,52401244 and 52201227)Henan Province Key Research and Development and Promotion Program(Scientific and Technological Breakthrough Project:232102240088 and 252102230078)+3 种基金the Key Research&Development and Promotion of Special Project(Scientific Problem Tackling)of Henan Province(252102230078)Doctoral Research Startup Fund Project of Henan Open University(BSJH-2025-04)Zhejiang Provincial Natural Science Foundation of China(LQ24B020005,LQ23B030001)China Postdoctoral Science Foundation(2024M762442).
文摘Electrocatalytic nitrate-to-ammonia conversion offers dual environmental and sustainable synthesis benefits,but achieving high efficiency with low-cost catalysts remains a major challenge.This review focuses on cobalt-based electrocatalysts,emphasizing their structural engineering for enhanced the performance of electrocatalytic nitrate reduction reaction(NO3RR)through dimensional control,compositional tuning,and coordination microenvironment modulation.Notably,by critically analyzing metallic cobalt,cobalt alloys,cobalt compounds,cobalt single atom and molecular catalyst configurations,we firstly establish correlations between atomic-scale structural features and catalytic performance in a coordination environment perspective for NO3RR,including the dynamic reconstruction during operation and its impact on active site.Synergizing experimental breakthroughs with computational modeling,we decode mechanisms underlying competitive hydrogen evolution suppression,intermediate adsorption-energy optimization,and durability enhancement in complex aqueous environments.The development of cobalt-based catalysts was summarized and prospected,and the emerging opportunities of machine learning in accelerating the research and development of high-performance catalysts and the configuration of series reactors for scalable nitrate-to-ammonia systems were also introduced.Bridging surface science and applications,it outlines a framework for designing multifunctional electrocatalysts to restore nitrogen cycle balance sustainably.
基金the staff of beamline BL13SSW at Shanghai Synchrotron Radiation Facility for experiments supports. This study was financially supported by the National Natural Science Foundation of China (No. 12205165)Hebei Province Innovation Ability Improvement Plan Project (No. 225676111H).
文摘Structural engineering of Pt-based nanoalloys is crucial for the rational design and manufacturing of high-performance and low-cost electrocatalysts for hydrogen evolution reaction(HER).Here,we reported PtNi nanoparticles with a refined size of 2.71 nm and regular strains loaded on carbon black,synthesized using the high-temperature liquid shock(HTLS)method.This approach offers significant advantages over conventional synthesis methods,including high scalability,rapid reaction rates,and precise control over the size and shape of nanocrystals.Importantly,the synthesized PtNi electrocatalysts demonstrate outstanding catalytic activity and long-term stability for HER,achieving low overpotentials of 19 and 203 mV at current densities of 10 and 1000 mA/cm^(2),respectively.The superior performance can be attributed to the combination of a refined particle size,lattice strains,and synergistic effects between Pt and Ni.This rapid liquid-state synthesis demonstrated here holds great potential for scalable and industrial manufacturing of micro-/nano-catalysts.
基金Funded by the National Natural Science Foundation of China Guangdong(No.22279096)。
文摘Silica nanoparticles-stabilized cobalt and nitrogen-doped carbon materials were synthesized through pyrolysis of metal-organic-framework of ZIF-67 supported by silica nanoparticles.The experimental results reveal that the introduction of the silica nanoparticles can stabilize the microstructure of the derived CoN-C materials,which in turn exhibits the promising electrocatalytic activity towards both oxygen reduction and oxygen evolution reactions.The optimized sample exhibits a better oxygen reduction activity than commercial Pt/C catalyst as confirmed by the positive shift of half-wave potential by 20 mV while it has a low overpotential of 273 mV for oxygen evolution reactions with the retained performance over 80%after 25,000 s of continuous operation.It is demonstrated that the introduction of support frame might be an effective way to improve the activity and stability of metal-organic-framework derived electrocatalyst with stabilized microstructure.
基金financially supported by the National Natural Science Foundation of China(Nos.22372143 and 22208281)the Hebei Natural Science Foundation(Nos.B2023203001 and B2025203050)the Science Research Project of Hebei Education Department(BJK2024122)。
文摘Rational design of non-noble electrocatalysts with high performance for oxygen evolution reaction(OER)still remains a challenge.In this study,a ZIF-derived electrocatalyst(Co@Fe-P)with a core-shell structure is designed by using Co-compounds as the core and PO_(4)^(3-)decorated Fe-compounds as the shell.The inner Co-core and outer Fe-shell are connected through Co-O-Fe and Fe-O-P linkage.The Co@Fe-P electrocatalyst exhibits an enhanced performance for OER with a low overpotential(280 mV),low Tafel slope(41.9 mV dec^(-1))at 10 mA cm^(-2),and a 60-h durability.The electron transfer from the CoOOH-core to the FeOOH-shell is greatly facilitated,which improves the OER activity of Co@Fe-P kinetically.Theoretical calculations indicate that the interaction of Co-O-Fe and Fe-O-P in Co@Fe-P reduces the overlap between the O 2p and Fe 3d orbitals,which greatly facilitates the transformation from*OH to*O during the OER process via the adsorbate evolution mechanism(AEM)pathway.This finding provides insight for the design of efficient electrocatalysts for OER.
基金financially supported by the National Natural Science Foundation of China(U21A20311,U24A2040,52171141,52272117)the Natural Science Foundation of Shandong Province(ZR2022JQ19)+3 种基金the Key Technology Research Project of Shandong Province(2023CXGC010202)the Taishan Industrial Experts Program(TSCX202306142)the Core Facility Sharing Platform of Shandong Universitythe Foundation of Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University。
文摘Co_(3)S_(4)electrocatalysts with mixed valences of Co ions and excellent structural stability possess favorable oxygen evolution reaction(OER)activity,yet challenges remain in fabricating rechargeable lithiumoxygen batteries(LOBs)due to their poor OER performance,resulting from poor electrical conductivity and overly strong intermediate adsorption.In this work,fancy double heterojunctions on 1T/2H-MoS_(2)@Co_(3)S_(4)(1T/2H-MCS)were constructed derived from the charge donation from Co to Mo ions,thus inducing the phase transformation of Mo S_(2)from 2H to 1T.The unique features of these double heterojunctions endow the1T/2H-MCS with complementary catalysis during charging and discharging processes.It is worth noting that 1T-Mo S2@Co3S4could provide fast Co-S-Mo electron transport channels to promote ORR/OER kinetics,and 2H-MoS_(2)@Co_(3)S_(4)contributed to enabling moderate egorbital occupancy when adsorbed with oxygen-containing intermediates.On the basis,the Li_(2)O_(2)nucleation route was changed to solution and surface dual pathways,improving reversible deposition and decomposition kinetics.As a result,1T/2H-MCS cathodes exhibit an improved electrocatalytic performance compared with those of Co_(3)S_(4)and Mo S2cathodes.This innovative heterostructure design provides a reliable strategy to construct efficient transition metal sulfide catalysts by improving electrical conductivity and modulating adsorption toward oxygenated intermediates for LOBs.
基金the foundation of Guangdong Engineering Technology Research Center for Hydrogen Energy and Fuel Cells,the Guangdong Provincial Department of Education Innovation Project(No.2022KQNCX056)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515110354 and 2021A1515110582)。
文摘Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.
基金Tianjin Natural Science Foundation (23JCYBJC00660)Tianjin Enterprise Science and Technology Commissioner Project (23YDTPJC00490)+2 种基金National Natural Science Foundation of China (52203066, 51973157, 61904123)China Postdoctoral Science Foundation Grant (2023M742135)State Key Laboratory of Membrane and Membrane Separation, Tiangong University。
文摘Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the key reactions in numerous renewable energy devices. Unlike conventional powdered catalysts, self-supported catalysts are extensively employed in oxygen electrocatalysis because of the enhanced electron-transfer rate, high specific surface area, and superior mechanical flexibility. Among the self-supported conductive substrates, carbon fiber usually exhibits several distinctive advantages, such as a straightforward preparation process, relatively low cost, good stability, and excellent conductivity. Against this background,carbon fiber-based self-supported electrocatalysts have been widely applied and studied in oxygen electrocatalysis, indicating a promising development direction in oxygen electrocatalyst research.Thus, it is essential to offer an overall summary of the research progress in this field to facilitate its subsequent development. Taking the regulatory mechanisms and modification methods as a starting point, this review comprehensively summarizes recent research on carbon fiber-based self-supported electrocatalysts in recent years. Firstly, a brief overview of the synthesis methods and regulatory mechanisms of carbon fiber-based self-supported electrocatalysts is given. Furthermore, the view also highlights the modification methods and research progress of self-supported electrocatalysts synthesized on carbon fiber-based substrates in recent years in terms of different dopant atoms. Finally, the prospects for the application of self-supported electrocatalysts based on carbon fiber in oxygen electrocatalysis and the possible future directions of their development are presented. This review summarizes recent developments and applications of self-supported bi-functional electrocatalysts with carbon fiber-based materials as the conducting substrate in oxygen electrocatalysis. It also lays a robust scientific foundation for the subsequent reasonable design of highly effective carbon fiber-based self-supported electrocatalysts.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.21978110 and 51772126)the Natural Science Foundation of Beijing Municipal(No.L182062)+6 种基金the Talents Project of Beijing Municipal Committee Organization Department(No.2018000021223ZK21)the Yue Qi Young Scholar Project of China University of Mining&Technology(Beijing)(No.2017QN17)the Fundamental Research Funds for the Central Universities(No.2020XJJD01 and 2020YJSJD01)Jilin Province Science and Technology Department Program(Nos.20200201187JC and 20190101009JH)the"13th five‐year"Science and Technology Project of Jilin Provincial Education Department(No.JJKH20200407KJ)Jilin Province Development and Reform Commission Program(No.2020C026‐3)Jilin Province Fund for Talent Development Program(No.[2019]874).
文摘The flexible self-supporting electrode can maintain good mechanical and electrical properties while retaining high specific capacity,which meets the requirements of flexible batteries.Lithium-sulfur batteries(LSBs),as a new generation of energy storage system,hold much higher theoretical energy density than traditional batteries,and they have attracted extensive attention from both the academic and industrial communities.Selection of a proper substrate material is important for the flexible self-supporting electrode.Carbon materials,with the advantages of light weight,high conductivity,strong structural plasticity,and low cost,provide the electrode with a large loading space for the active material and a conductive network.This makes the carbon materials meet the mechanical and electrochemical requirements of flexible electrodes.In this paper,the commonly used fabrication methods and recent research progresses of the flexible self-supporting cathode with a carbon material as the substrate are introduced.Various sulfur loading methods are summarized,which provides useful information for the structural design of the cathode.As the first review article of the carbon-based flexible self-supporting LSB cathodes,it provides valuable guidance for the researchers working in the field of LSB.
基金financially supported by the National Key Research and Development Program of China (2017YFA0402800)the National Natural Science Foundation of China (51772285)the National Synchrotron Radiation Laboratory at USTC.
文摘Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.The oxygen evolution reaction(OER)is considered as the bottleneck reaction in an overall water splitting system because it involves 4e- and 4H+ transfer processes.Currently,it is highly desirable to explore low-cost alternative catalysts for OER at ambient conditions.Herein,we report for the first time that nickel phosphide(Ni2P)nanosheets can be facilely grown on Fe foam(FF)as an efficient electrocatalyst for OER with excellent durability and catalytic activity under alkaline conditions.To reach a current density of 10 m A/cm2,the Ni2P-FF catalyst required a low overpotential of only 198 mV for OER.The catalyst’s high OER activity and durability were well maintained at a high current density.The required overpotentials were only 267 and 313 mV to achieve the current densities of 100 and 300 m A/cm2,respectively.The combination of low-cost Fe foam with Ni2P provides a promising low-cost catalyst for large-scale application of electrocatalytic water splitting.
文摘Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x)integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2)under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2)under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2)for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2)at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.
基金supported by the National Key Research and Development Program of China(2018YFB1106303)Scientific Research Foundation of CAUC(2017QD10S).
文摘The integration of topology optimization(TO)and additive manufacturing(AM)technologies can create significant synergy benefits,while the lack of AM-friendly TO algorithms is a serious bottleneck for the application of TO in AM.In this paper,a TO method is proposed to design self-supporting structures with an explicit continuous self-supporting constraint,which can be adaptively activated and tightened during the optimization procedure.The TO procedure is suitable for various critical overhang angles(COA),which is integrated with build direction assignment to reduce performance loss.Besides,a triangular directional self-supporting constraint sensitivity filter is devised to promote the downward evolution of structures and maintain stability.Two numerical examples are presented;all the test cases have successfully converged and the optimized solutions demonstrate good manufacturability.In the meanwhile,a fully self-supporting design can be obtained with a slight cost in performance through combination with build direction assignment.
基金financially supported by the National Natural Science Foundation of China(Nos.32171709 and 32271791)China Postdoctoral Science Foundation(No.2023M743972)。
文摘Hard carbon stands out as the most promising candidate for anodes in sodium-ion battery.Nevertheless,addressing the challenges of low initial Coulombic efficiency and rate performance is crucial for practical applications.In this study,we employed a dimensionally designed approach,using six different biomass precursors,to preserve their inherent fine hierarchical morphological structures and appearances during the synthesis of selfsupporting carbon materials.Benefiting from its low-tortuosity structure that facilitates electron and ion transport,as well as its surface-enriched C=O functional groups and significant closed micropore areas,the obtained carbon material exhibits excellent electrochemical performance in sodium-ion storage,demonstrated by finite element simulation.Notably,the carbonized basswood exhibited a remarkable initial Coulombic efficiency of up to 92.4%and demonstrated outstanding rate performance,achieving a capacity of 223.3 mAh·g^(-1)at a high current density of2 A·g^(-1).In addition,thorough investigation was conducted on the influence of microstructure on the sodium storage behavior of hard carbon.Ex situ X-ray diffraction(XRD)was used to confirm that the capacity in the plateau region originates from interlayer insertion and closed-pore filling,which is consistent with the results obtained from smallangle X-ray scattering.These findings underscore the immense potential of leveraging surface functionalization and structural design to bolster the performance of hard carbon,paving the way for promising future advancements in this field.
基金financially supported by the National Natural Science Foundation of China(Nos.21875147 and 51991351)the Fundamental Research Funds for the Central Universities。
文摘Due to the important role of oil source in our life,the separation of water-in-oil emulsion is urgent and necessary.Membrane seperation technology has been an efficient and widely used method in separating oil-water separation.Herein,we report a versatile approach to fabricate surface carbonized membranes with self-standing property from biomass-derived precursor by synergistic charring of phytic acid,arginine and filter paper.The obtained membrane exhibited superhydrophobicity in oil,excellent fouling resistance,and self-supporting ability.The membrane can be cycle-used at least 12 times with high permeation flux(up to 1380 L·m^(-2)·h^(-1))and separation efficiency(up to 99.4%).
