The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a serie...The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a series of RuCo/C catalysts were synthesized by NaBH4 reduction method under the premise that the total metal mass percentage was 20%.X-ray diffraction(XRD)patterns and scanning electron microscopy(SEM)confirmed the formation of single-phase nanoparticles with an average size of 33 nm.Cyclic voltammograms(CV)and linear sweep voltammograms(LSV)tests indicated that RuCo(2:1)/C catalyst had the optimal ORR properties.Additionally,the RuCo(2:1)/C catalyst remarkably sustained 98.1% of its activity even after 3000 cycles,surpassing the performance of Pt/C(84.8%).Analysis of the elemental state of the catalyst surface after cycling using X-ray photoelectron spectroscopy(XPS)revealed that the Ru^(0) percentage of RuCo(2:1)/C decreased by 2.2%(from 66.3% to 64.1%),while the Pt^(0) percentage of Pt/C decreased by 7.1%(from 53.3% to 46.2%).It is suggested that the synergy between Ru and Co holds the potential to pave the way for future low-cost and highly stable ORR catalysts,offering significant promise in the context of PEMFCs.展开更多
High-entropy oxides(HEOs)derive their exceptional properties from the atomic-level homogenization of multiple constituent elements within the crystal lattice,which induces a sophisticated local environment that fundam...High-entropy oxides(HEOs)derive their exceptional properties from the atomic-level homogenization of multiple constituent elements within the crystal lattice,which induces a sophisticated local environment that fundamentally reconfigures electron density distributions and coordination environment at active sites.However,the mechanisms by which multi-component systems in HEOs precisely regulate high-activity catalytic sites remain poorly understood.This work addresses this gap by designing medium-entropy perovskite oxides through the strategic incorporation of transition metals with distinct electronegativities and ionic radii,aiming to unravel how local environmental modifications impact the energy band location,coordination states,and adsorption behavior of the Co site.A family of A_(2)BO_(4)-type medium-entropy oxides PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)M_(0.2))O_(4)(M=Sc,Cr,Mn)was successfully synthesized.Divergent atomic properties among Sc,Cr,and Mn(electronegativity,ionic size,and metal-oxygen bond strength)triggered pronounced electron redistribution,effectively tuning the d-band center of Co.Remarkably,Cr substitution significantly enhanced O_(2) adsorption at Co-active sites,as indicated by an elongated O-O bond length(1.234Å→1.279Å).Concurrently,Cr doping destabilized the M'-O-Cr bonds(M'=Fe,Co,Ni,Cu)and lowered the thermodynamic barrier for oxygen vacancy formation.Electrochemical tests revealed that PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)Cr_(0.2))O_(4)(PSMO-Cr)exhibited the highest electrical conductivity and fastest oxygen surface exchange kinetics.At 700℃,the area-specific resistance(ASR)of the PSMO-Cr cathode was 0.07Ωcm^(2).Corresponding fuel cells achieved a maximum power density of 0.76 W cm^(-2).In electrolysis mode,the maximum current density reached 0.56 A cm^(-2) under 1.3 V at 700℃using PSMO-Cr as the anode.These results demonstrate that PSMO-Cr is a promising bifunctional catalyst for energy conversion applications.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
The development of economical,highly efficient,and stable bifunctional electrocatalysts for both the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR)remains a critical focus in advancing rechargeab...The development of economical,highly efficient,and stable bifunctional electrocatalysts for both the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR)remains a critical focus in advancing rechargeable metal-air battery systems.Significant progress has been made in the design of high-performance bifunctional electrocatalysts,the development of novel oxygen electrode architectures,and the in-depth understanding of electrocatalytic mechanisms through combined experimental and computational studies.This work provides a comprehensive review of recent advancements in design strategies for oxygen catalysts,including homogeneous electrodes,asymmetric electrodes,and biomimetic electrodes,are thoroughly discussed and summarized.Then,the advanced catalyst modification strategies for ORR/OER are summarized,focusing on critical factors such as enhancement effect of metal/nonmental and synergistic enhancement effect in multiple catalyst.Subsequently,a representative performance evaluation is presented,based on the reported oxygen electrodes used in rechargeable metal-air battery applications.By focusing on these key areas,the review outlines the current challenges and future prospects for the development of bifunctional oxygen electrocatalysts,aiming to guide the design of high-performance bifunctional electrocatalysts and to elucidate the underlying mechanisms involved.展开更多
Iron-based single-atom(SA)catalysts offer a promising alternative to noble-metal catalysts for the oxygen reduction reaction(ORR),yet their limited intrinsic activity and durability hinder practical energy device appl...Iron-based single-atom(SA)catalysts offer a promising alternative to noble-metal catalysts for the oxygen reduction reaction(ORR),yet their limited intrinsic activity and durability hinder practical energy device applications.Herein,we introduce a novel TiN/TiC-supported Fe SA catalyst(TiNC/Fe-NC)with a hierarchical heterostructure that synergistically enhances Fe-N_(x) site activity and accessibility.The TiNC/Fe-NC catalyst achieves outstanding ORR performances,with half-wave potentials(E_(1/2))of 0.852 V in acidic media and 0.942 V in alkaline media.Theoretical simulations reveal that strong electronic interaction and efficient charge transfer between TiNC and Fe-N_(x) sites optimize the adsorption energetics of key ORR intermediates,driving the enhanced activity.Remarkably,TiNC effectively scavenges reactive oxygen radicals generated at the Fe centers,ensuring exceptional durability with a minimal 28 mV loss in E_(1/2) after 10,000 cycles at 80℃in acid media.In practical applications,TiNC/Fe-NC delivers peak power densities of 306 mW cm^(-2) in zinc-air battery and 732 mW cm^(-2) in proton exchange membrane fuel cells,with remarkable long-term stability.This work establishes TiNC/Fe-NC as a highperformance,durable catalyst for advanced energy storage and conversion technologies.展开更多
Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-...Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-doped carbon(Fe/SNC)via in situ incorporation of 2-aminothiazole molecules into zeolitic imidazolate framework-8(ZIF-8)through coordination between metal ions and organic ligands.Sulfur and nitrogen doping in carbon supports effectively modulates the electronic structure of the catalyst,increases the Brunauer-Emmett-Teller surface area,and exposes more Fe-N_(x)active centers.Fe-loaded,S and N co-doped carbon with Fe/S molar ratio of 1:10(Fe/SNC-10)exhibits a half-wave potential of 0.902 V vs.RHE.After 5000 cycles of cyclic voltammetry,its half-wave potential decreases by only 20 mV vs.RHE,indicating excellent stability.Due to sulfur s lower electronegativity,the electronic structure of the Fe-N_(x)active center is modulated.Additionally,the larger atomic radius of sulfur introduces defects into the carbon support.As a result,Fe/SNC-10 demonstrates superior ORR activity and stability in alkaline solution compared with Fe-loaded N-doped carbon(Fe/NC).Furthermore,the zinc-air battery assembled with the Fe/SNC-10 catalyst shows enhanced performance relative to those assembled with Fe/NC and Pt/C catalysts.This work offers a novel design strategy for advanced energy storage and conversion applications.展开更多
Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction...Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction(ORR)and chlorideinduced degradation over conventional catalysts.In this study,we proposed a universal synthetic strategy to construct heteroatom axially coordinated Fe–N_(4) single-atom seawater catalyst materials(Cl–Fe–N_(4) and S–Fe–N_(4)).X-ray absorption spectroscopy confirmed their five-coordinated square pyramidal structure.Systematic evaluation of catalytic activities revealed that compared with S–Fe–N_(4),Cl–Fe–N_(4) exhibits smaller electrochemical active surface area and specific surface area,yet demonstrates higher limiting current density(5.8 mA cm^(−2)).The assembled zinc-air batteries using Cl–Fe–N_(4) showed superior power density(187.7 mW cm^(−2) at 245.1 mA cm^(−2)),indicating that Cl axial coordination more effectively enhances the intrinsic ORR activity.Moreover,Cl–Fe–N_(4) demonstrates stronger Cl−poisoning resistance in seawater environments.Chronoamperometry tests and zinc-air battery cycling performance evaluations confirmed its enhanced stability.Density functional theory calculations revealed that the introduction of heteroatoms in the axial direction regulates the electron center of Fe single atom,leading to more active reaction intermediates and increased electron density of Fe single sites,thereby enhancing the reduction in adsorbed intermediates and hence the overall ORR catalytic activity.展开更多
The development of atomically dispersed multi-metallic catalysts is imperative for tailoring catalytic performance and elucidating structure-activity relationships.However,synthesizing such precisely engineered archit...The development of atomically dispersed multi-metallic catalysts is imperative for tailoring catalytic performance and elucidating structure-activity relationships.However,synthesizing such precisely engineered architectures while maintaining atomic dispersion of distinct metal centers remains a formidable challenge due to thermodynamic instability and synthetic complexity.We herein propose a topological confinement pre-anchoring strategy via pre-anchoring spatially resolved Zn/Fe dual-metal sources in a structurally engineered metal-organic framework precursor to synthesize atomically dispersed ZnFe bimetallic single-atom catalysts.Extended X-ray absorption fine structure measurements and X-ray absorption near-edge structure reveal that the atomically dispersed Zn/Fe metal sites and electronic redistribution in ZnFe bimetallic single-atom catalysts.The ultrahigh surface area,hierarchical pore,and synergistic effect between Zn/Fe can greatly favor the exposure of the active site,mass transport,and improvement of intrinsic activity.Consequently,the ZnFe bimetallic single-atom catalyst demonstrates superior oxygen reduction reaction performance,achieving a half-wave potential of 0.86 V and delivering a kinetic current density of 10.1 mA cm^(-2)at 0.85 V versus RHE in 0.1 m KOH electrolyte.These metrics not only surpass those of commercial Pt/C,but also rival the highest-performing catalysts reported to date.The Zn-air battery built with ZnFe bimetallic single-atom catalyst exhibits high power density(278.5 mW cm^(-2))and specific discharging capacities(657 mAh g^(-1)).This work provides a new design pathway for constructing atomically dispersed multi-metal electrocatalysts for high-performance energy-related applications.展开更多
Optimizing the oxygen reduction reaction(ORR)kinetics requires precise control of intermediate adsorption at active sites,which can be achieved through orbital engineering by regulating the electronic structure.This s...Optimizing the oxygen reduction reaction(ORR)kinetics requires precise control of intermediate adsorption at active sites,which can be achieved through orbital engineering by regulating the electronic structure.This study addresses the challenge by exploring how modulation of the 3d-orbital electronic structure of FeN_(4) active sites influences ORR electrocatalysis.To realize this,a catalyst composed of Fe_(3)C nanoparticles and FeN_(4) single atoms anchored on carbon black(Fe_(3)C-FeN_(4)/CB)was synthesized via a synergistic strategy of spatial confinement and atmosphere control.This unique heterostructure creates interfaces between Fe_(3)C and FeN_(4) that modulate the electronic configuration of the FeN_(4) center,transforming its geometry from square-planar to quasi-octahedral.Spectroscopic characterizations and theoretical calculations reveal that this orbital modulation results in a downward shift of the Fe dband center,altering the reaction pathway and lowering the energy barrier for ORR.Consequently,the Fe_(3)C-FeN_(4)/CB catalyst exhibits outstanding ORR activity,four-electron selectivity,excellent methanol tolerance,and remarkable electrochemical stability.When applied in a zinc-air battery,it achieves a peak power density of 178.4 mW cm^(-2)and superior cycling stability compared to commercial Pt/C catalysts.This work provides valuable insights into heterointerface-induced orbital modulation as a promising design principle for high-performance ORR electrocatalysts.展开更多
α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the ...α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the performance ofα-MnO_(2) electrodes by systematically varying theα-MnO_(2)-to-Vulcan ratio within the catalyst layer.Electrodes are evaluated in a gas diffusion electrode(GDE)half-cell,where an optimized catalyst layer composition leads to significantly improved ORR performance.By finetuning both theα-MnO_(2)-to-Vulcan ratio and theα-MnO_(2) loading,the electrode outperforms a commercial MnO_(2)-based electrode and approaches the performance of the Pt/C benchmark.The improvement is attributed to the presence of a three-dimensional(3D)Vulcan network electronically connecting catalytically activeα-MnO_(2) sites with the substrate.Additionally,the optimized electrodes are employed in a prototype Al-O_(2) flow cell.Under constant oxygen flow,power densities exceed 250 mW cm^(-2),which is significantly higher than that of conventional Al-air batteries.Electrochemical impedance spectroscopy combined with distribution of relaxation times(DRT)analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode.The analysis reveals that the anode contributes more than twice as much impedance as the cathode,highlighting the need for further anode optimization.This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell.Subsequent measurements in an Al-O_(2) flow cell validate the approach.The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.展开更多
Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-perform...Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-performance biomass-derived ORR catalysts with an asymmetric Fe-N_(3)P configuration was prepared by a simple pyrolysis-etching technique,where carboxymethyl cellulose(CMC)was used as the carbon source,urea and 1,10-phenanthroline iron complex(FePhen)as additives,and Na_(3)PO_(4)as the phosphorus dopant and a pore-forming agent.The CMC-derived FeNPC catalyst displayed a large specific area(BET:1235 m^(2)g^(-1))with atomically dispersed Fe-N_(3)P active sites,which exhibited superior ORR activity and stability in alkaline solution(E_(1/2)=0.90 V vs.RHE)and Zn-air batteries(P_(max)=149 mW cm^(-2))to commercial Pt/C catalyst(E_(1/2)=0.87 V,P_(max)=118 mW cm^(-2))under similar experimental conditions.This work provides a feasible and costeffective route toward highly efficient ORR catalysts and their application to Zn-air batteries for energy conversion.展开更多
Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst m...Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst modified with black phosphorus(BP)nanodots(BPNDs-Pt/C)by using a facile ultrasonic mixing method.Experimental and computational investigations reveal that the electron transfer from BP to Pt leads to weak adsorption of hydroxyl groups on the Pt surface.As a result,the BPNDs-Pt/C catalyst exhibits efficient activity and anti-methanol ability for cathodic oxygen reduction electrocatalysis in an acidic medium.Additionally,it demonstrates high activity for oxygen reduction reaction(ORR)in an alternative alkaline system with cation exchange membrane and eliminable methanol penetration.This work highlights the feasibility of using non-metallic elements to regulate the electronic structure and surface properties of Pt-based nanomaterials.Furthermore,the designed BPNDs-Pt/C electrocatalyst,with controllable ORR performance,can be applied across various scenarios based on demand.展开更多
Nitrogen-doping of carbon support(N-C)for platinum(Pt)nanoparticles to form Pt/N-C catalyst represents an effective strategy to promote the electrocatalysis of cathodic oxygen reduction reaction(ORR)in proton exchange...Nitrogen-doping of carbon support(N-C)for platinum(Pt)nanoparticles to form Pt/N-C catalyst represents an effective strategy to promote the electrocatalysis of cathodic oxygen reduction reaction(ORR)in proton exchange membrane fuel cells.For fundamental understanding,clearly identifying the metalsupport effect on enhancement mechanisms of ORR electrocatalysis is definitely needed.In this work,the impact of Pt-support interaction via interfacial Pt-N coordination on electrocatalytic ORR activity and stability in Pt/N-C catalyst is deeply studied through structural/compositional characterizations,electrochemical measurements and theoretical DFT-calculations/AIMD-simulations.The resulting Pt/N-C catalyst exhibits a superior electrocatalytic performance compared to the commercial Pt/C catalyst in both half-cell and H_(2)-O_(2)fuel cell.Experimental and theoretical results reveal that the interfacial Pt-N coordination enables electron transfer from N-C support to Pt nanoparticles,which can weaken the adsorption strength of oxygen intermediates on Pt surface to improve ORR activity and induce the strong Pt-support interaction to enhance electrochemical stability.展开更多
Selective electrocatalysis of two-electron oxygen reduction reaction(2e^(-)ORR)has been recognized as a sustainable and on-site process for hydrogen peroxide(H_(2)O_(2))production.Great progress has been achieved for ...Selective electrocatalysis of two-electron oxygen reduction reaction(2e^(-)ORR)has been recognized as a sustainable and on-site process for hydrogen peroxide(H_(2)O_(2))production.Great progress has been achieved for 2e^(-)ORR in alkaline media.However,it is challenged by insufficient activity and selectiv-ity of the catalysts in acidic electrolytes.Herein,we report sulfur-poisoned PtNi/C catalysts(PtNiSx/C)that could regulate ORR from the 4e^(-)to 2e^(-)pathway.The identified PtNiS0.6/C offers high activity in terms of onset potential of∼0.69 V(vs.RHE)and∼80%selectivity.The mass activity is also compara-ble and outperforms representative Pt-based precious and transition-metal-based catalysts.In addition,it is interestingly found that the Faradaic efficiency further increased to 95%during the long-term elec-trolysis test due to Ni atom surface migration.The electrochemical production of the H_(2)O_(2)system was applied to the electro-Fenton process,which has realized the effective degradation of organic pollutants.This work offers a strategy by sulfur poisoning PtNi/C catalyst to realize Pt-based 2e^(-)ORR active catalysts to electrolysis of H_(2)O_(2)in acidic media.展开更多
The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel cells.Herein,we report a...The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel cells.Herein,we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dualmetal sites on N-doped carbon(denoted(FeMn-DA)-N-C)for both anion-exchange membrane fuel cells(AEMFC)and proton exchange membrane fuel cells(PEMFC).The(FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N_(4)and Mn-N_(4)sites on the carbon surface,yielded via a facile doping-adsorption-pyrolysis route.The introduction of Mn carries several advantageous attributes:increasing the number of active sites,effectively anchoring Fe due to effective electron transfer to Mn(revealed by X-ray absorption spectroscopy and density-functional theory(DFT),thus preventing the aggregation of Fe),and effectively circumventing the occurrence of Fenton reaction,thus reducing the consumption of Fe.The(FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1 M KOH and 0.1 M HClO_(4),respectively,as well as outstanding stability.As manifested by DFT calculations,the introduction of Mn affects the electronic structure of Fe,down-shifts the d-band Fe active center,accelerates the desorption of OH groups,and creates higher limiting potentials.The AEMFC and PEMFC with(FeMn-DA)-N-C as the cathode catalyst display high power densities of 1060 and 746 mW cm^(-2),respectively,underscoring their promising potential for practical applications.Our study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.展开更多
The development of an e fficacious and easily prepared no nprecious metal electrocatalyst is crucial for the oxygen reduction reaction(ORR).This work used a dual template method to prepare the amorphous rare earth-bas...The development of an e fficacious and easily prepared no nprecious metal electrocatalyst is crucial for the oxygen reduction reaction(ORR).This work used a dual template method to prepare the amorphous rare earth-based catalyst PrO_(x)-NC,and optimized the calcination temperature and proportion.The PrO_(x)-NC-900 catalyst has high durability and activity and exhibits superior ORR performance in alkaline electrolytes with an onset potential(E_(0))of 0.96 V and a half-wave potential(E_(1/2))of 0.85 V.The research results indicate that the ORR performance of rare earth oxide composite carbon catalysts can be improved by adjusting oxygen vacancies(Ov).In addition,high specific surface area,N rich defect carbon.increased oxygen vacancies,and the synergistic effect of oxygen vacancies and N-doped carbon interfacial layer play a significant part in the enhancement of ORR.The performance of the zinc air battery assembled with PrO_(x)-NC-900 is significantly improved,and rare earth oxides and carbon frameworks originating from metal organic frameworks(MOFs)contribute to the oxygen electrocatalyst and electron transfer rate of the zinc air battery.This catalyst provides promising information for the development of rare earth metal oxide nanostructures as potential candidate materials for ORR in alkaline media.展开更多
Alloying transition metals with Pt is an effective strategy for optimizing Pt-based catalysts toward the oxygen reduction reaction(ORR).Atomic ordered intermetallic compounds(IMC)provide unique electronic and geometri...Alloying transition metals with Pt is an effective strategy for optimizing Pt-based catalysts toward the oxygen reduction reaction(ORR).Atomic ordered intermetallic compounds(IMC)provide unique electronic and geometrical effects as well as stronger intermetallic interactions due to the ordered arrangement of metal atoms,thus exhibiting superior electrocata-lytic activity and durability.However,quantitatively analyzing the ordering degree of IMC and exploring the correlation between the ordering degree and ORR activity remains extremely challenging.Herein,a series of ternary Pt_(2)NiCo interme-tallic catalysts(o-Pt_(2)NiCo)with different ordering degree were synthesized by annealing temperature modulation.Among them,the o-Pt_(2)NiCo which annealed at 800℃for two hours exhibits the highest ordering degree and the optimal ORR ac-tivity,which the mass activity of o-Pt_(2)NiCo is 1.8 times and 2.8 times higher than that of disordered Pt_(2)NiCo alloy and Pt/C.Furthermore,the o-Pt_(2)NiCo still maintains 70.8%mass activity after 30,000 potential cycles.Additionally,the ORR activity test results for Pt_(2)NiCo IMC with different ordering degree also provide a positive correlation between the ordering degree and ORR activity.This work provides a prospective design direction for ternary Pt-based electrocatalysts.展开更多
The poor electronic conductivity of metal-organic framework(MOF)materials hinders their direct application in the field of electrocatalysis in fuel cells.Herein,we proposed a strategy of embedding carbon nanotubes(CNT...The poor electronic conductivity of metal-organic framework(MOF)materials hinders their direct application in the field of electrocatalysis in fuel cells.Herein,we proposed a strategy of embedding carbon nanotubes(CNTs)during the growth process of MOF crystals,synthesizing a metalloporphyrin-based MOF catalyst TCPPCo-MOF-CNT with a unique CNT-intercalated MOF structure.Physical characterization revealed that the CNTs enhance the overall conductivity while retaining the original characteristics of the MOF and metalloporphyrin.Simultaneously,the insertion of CNTs generated adequate mesopores and created a hierarchical porous structure that enhances mass transfer efficiency.X-ray photoelectron spectroscopic analysis confirmed that the C atom in CNT changed the electron cloud density on the catalytic active center Co,optimizing the electronic structure.Consequently,the E_(1/2) of the TCPPCo-MOF-CNT catalyst under neutral conditions reached 0.77 V(vs.RHE),outperforming the catalyst without CNTs.When the TCPPCo-MOF-CNT was employed as the cathode catalyst in assembling microbial fuel cells(MFCs)with Nafion-117 as the proton exchange membrane,the maxi-mum power density of MFCs reached approximately 500 mW·m^(-2).展开更多
The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this wor...The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this work,we strategi-cally engineer the active site structure of Co-N-C via B substitution,which is accomplished by the pyrolysis of ammonium borate.During this process,the in-situ generated NH_(3)gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure.The well-designed CoB_(1)N_(3)active site endows Co with higher charge density and stronger adsorption energy toward oxygen species,potentially accelerating ORR kinetics.As expected,the resulting Co-B/N-C catalyst exhibited superior ORR performance over Co-N-C counterpart,with 40 mV,and fivefold en-hancement in half-wave potential and turnover frequency(TOF).More importantly,the excellent ORR performance could be translated into membrane electrode assembly(MEA)in a fuel cell test,delivering an impressive peak power density of 824 mW·cm^(-2),which is currently the best among Co-based catalysts under the same conditions.This work not only demon-strates an effective method for designing advanced catalysts,but also affords a highly promising non-precious metal ORR electrocatalyst for fuel cell applications.展开更多
Development of robust electrocatalyst for oxygen reduction reaction(ORR)in a seawater electrolyte is the key to realize seawater electrolyte-based zinc-air batteries(SZABs).Herein,constructing a local electric field c...Development of robust electrocatalyst for oxygen reduction reaction(ORR)in a seawater electrolyte is the key to realize seawater electrolyte-based zinc-air batteries(SZABs).Herein,constructing a local electric field coupled with chloride ions(Cl-)fixation strategy in dual single-atom catalysts(DSACs)was proposed,and the resultant catalyst delivered considerable ORR performance in a seawater electrolyte,with a high half-wave potential(E_(1/2))of 0.868 V and a good maximum power density(Pmax)of 182 mW·cm^(−2)in the assembled SZABs,much higher than those of the Pt/C catalyst(E_(1/2):0.846 V;Pmax:150 mW·cm^(−2)).The in-situ characterization and theoretical calculations revealed that the Fe sites have a higher Cl^(−)adsorption affinity than the Co sites,and preferentially adsorbs Cl^(−)in a seawater electrolyte during the ORR process,and thus constructs a low-concentration Cl^(−)local microenvironment through the common-ion exclusion effect,which prevents Cl^(−)adsorption and corrosion in the Co active centers,achieving impressive catalytic stability.In addition,the directional charge movement between Fe and Co atomic pairs establishes a local electric field,optimizing the adsorption energy of Co sites for oxygen-containing intermediates,and further improving the ORR activity.展开更多
基金Funded by the 111 Project(No.B17034)Open Project of Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle(No.ZDSYS202212)+1 种基金Innovative Research Team Development Program of Ministry of Education of China(No.IRT_17R83)the Science and Technology Project of China Southern Power Grid Co.,Ltd.(No.GDKJXM20222546)。
文摘The development of Pt-free catalysts for the oxygen reduction reaction(ORR)is a great issue for meeting the cost challenges of proton exchange membrane fuel cells(PEMFCs)in commercial applications.In this work,a series of RuCo/C catalysts were synthesized by NaBH4 reduction method under the premise that the total metal mass percentage was 20%.X-ray diffraction(XRD)patterns and scanning electron microscopy(SEM)confirmed the formation of single-phase nanoparticles with an average size of 33 nm.Cyclic voltammograms(CV)and linear sweep voltammograms(LSV)tests indicated that RuCo(2:1)/C catalyst had the optimal ORR properties.Additionally,the RuCo(2:1)/C catalyst remarkably sustained 98.1% of its activity even after 3000 cycles,surpassing the performance of Pt/C(84.8%).Analysis of the elemental state of the catalyst surface after cycling using X-ray photoelectron spectroscopy(XPS)revealed that the Ru^(0) percentage of RuCo(2:1)/C decreased by 2.2%(from 66.3% to 64.1%),while the Pt^(0) percentage of Pt/C decreased by 7.1%(from 53.3% to 46.2%).It is suggested that the synergy between Ru and Co holds the potential to pave the way for future low-cost and highly stable ORR catalysts,offering significant promise in the context of PEMFCs.
基金supported by the National Natural Science Foundation of China(51872078,52272197,52572219)Heilongjiang Provincial Natural Science Foundation of China(LH2024E106)。
文摘High-entropy oxides(HEOs)derive their exceptional properties from the atomic-level homogenization of multiple constituent elements within the crystal lattice,which induces a sophisticated local environment that fundamentally reconfigures electron density distributions and coordination environment at active sites.However,the mechanisms by which multi-component systems in HEOs precisely regulate high-activity catalytic sites remain poorly understood.This work addresses this gap by designing medium-entropy perovskite oxides through the strategic incorporation of transition metals with distinct electronegativities and ionic radii,aiming to unravel how local environmental modifications impact the energy band location,coordination states,and adsorption behavior of the Co site.A family of A_(2)BO_(4)-type medium-entropy oxides PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)M_(0.2))O_(4)(M=Sc,Cr,Mn)was successfully synthesized.Divergent atomic properties among Sc,Cr,and Mn(electronegativity,ionic size,and metal-oxygen bond strength)triggered pronounced electron redistribution,effectively tuning the d-band center of Co.Remarkably,Cr substitution significantly enhanced O_(2) adsorption at Co-active sites,as indicated by an elongated O-O bond length(1.234Å→1.279Å).Concurrently,Cr doping destabilized the M'-O-Cr bonds(M'=Fe,Co,Ni,Cu)and lowered the thermodynamic barrier for oxygen vacancy formation.Electrochemical tests revealed that PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)Cr_(0.2))O_(4)(PSMO-Cr)exhibited the highest electrical conductivity and fastest oxygen surface exchange kinetics.At 700℃,the area-specific resistance(ASR)of the PSMO-Cr cathode was 0.07Ωcm^(2).Corresponding fuel cells achieved a maximum power density of 0.76 W cm^(-2).In electrolysis mode,the maximum current density reached 0.56 A cm^(-2) under 1.3 V at 700℃using PSMO-Cr as the anode.These results demonstrate that PSMO-Cr is a promising bifunctional catalyst for energy conversion applications.
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(52302084)the National Key Research and Development Program of China(2022YFE0138900)+1 种基金Fundamental Research Funds for the Central Universities(2232025D-24)the Qin Shen Scholar Program of Jiaxing University。
文摘The development of economical,highly efficient,and stable bifunctional electrocatalysts for both the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR)remains a critical focus in advancing rechargeable metal-air battery systems.Significant progress has been made in the design of high-performance bifunctional electrocatalysts,the development of novel oxygen electrode architectures,and the in-depth understanding of electrocatalytic mechanisms through combined experimental and computational studies.This work provides a comprehensive review of recent advancements in design strategies for oxygen catalysts,including homogeneous electrodes,asymmetric electrodes,and biomimetic electrodes,are thoroughly discussed and summarized.Then,the advanced catalyst modification strategies for ORR/OER are summarized,focusing on critical factors such as enhancement effect of metal/nonmental and synergistic enhancement effect in multiple catalyst.Subsequently,a representative performance evaluation is presented,based on the reported oxygen electrodes used in rechargeable metal-air battery applications.By focusing on these key areas,the review outlines the current challenges and future prospects for the development of bifunctional oxygen electrocatalysts,aiming to guide the design of high-performance bifunctional electrocatalysts and to elucidate the underlying mechanisms involved.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSITRS2024-00345635 and RS-2021-NR060090)the Research Grant Council of the Hong Kong SAR(PolyU15302824)。
文摘Iron-based single-atom(SA)catalysts offer a promising alternative to noble-metal catalysts for the oxygen reduction reaction(ORR),yet their limited intrinsic activity and durability hinder practical energy device applications.Herein,we introduce a novel TiN/TiC-supported Fe SA catalyst(TiNC/Fe-NC)with a hierarchical heterostructure that synergistically enhances Fe-N_(x) site activity and accessibility.The TiNC/Fe-NC catalyst achieves outstanding ORR performances,with half-wave potentials(E_(1/2))of 0.852 V in acidic media and 0.942 V in alkaline media.Theoretical simulations reveal that strong electronic interaction and efficient charge transfer between TiNC and Fe-N_(x) sites optimize the adsorption energetics of key ORR intermediates,driving the enhanced activity.Remarkably,TiNC effectively scavenges reactive oxygen radicals generated at the Fe centers,ensuring exceptional durability with a minimal 28 mV loss in E_(1/2) after 10,000 cycles at 80℃in acid media.In practical applications,TiNC/Fe-NC delivers peak power densities of 306 mW cm^(-2) in zinc-air battery and 732 mW cm^(-2) in proton exchange membrane fuel cells,with remarkable long-term stability.This work establishes TiNC/Fe-NC as a highperformance,durable catalyst for advanced energy storage and conversion technologies.
基金financial support of the National Natural Science Foundation of China(No.52472271)the National Key Research and Development Program of China(No.2023YFE0115800)。
文摘Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-doped carbon(Fe/SNC)via in situ incorporation of 2-aminothiazole molecules into zeolitic imidazolate framework-8(ZIF-8)through coordination between metal ions and organic ligands.Sulfur and nitrogen doping in carbon supports effectively modulates the electronic structure of the catalyst,increases the Brunauer-Emmett-Teller surface area,and exposes more Fe-N_(x)active centers.Fe-loaded,S and N co-doped carbon with Fe/S molar ratio of 1:10(Fe/SNC-10)exhibits a half-wave potential of 0.902 V vs.RHE.After 5000 cycles of cyclic voltammetry,its half-wave potential decreases by only 20 mV vs.RHE,indicating excellent stability.Due to sulfur s lower electronegativity,the electronic structure of the Fe-N_(x)active center is modulated.Additionally,the larger atomic radius of sulfur introduces defects into the carbon support.As a result,Fe/SNC-10 demonstrates superior ORR activity and stability in alkaline solution compared with Fe-loaded N-doped carbon(Fe/NC).Furthermore,the zinc-air battery assembled with the Fe/SNC-10 catalyst shows enhanced performance relative to those assembled with Fe/NC and Pt/C catalysts.This work offers a novel design strategy for advanced energy storage and conversion applications.
基金funded by the Innovative Research Group Project of the National Natural Science Foundation of China(52121004)the Research Development Fund(No.RDF-21-02-060)by Xi’an Jiaotong-Liverpool University+1 种基金support received from the Suzhou Industrial Park High Quality Innovation Platform of Functional Molecular Materials and Devices(YZCXPT2023105)the XJTLU Advanced Materials Research Center(AMRC).
文摘Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction(ORR)and chlorideinduced degradation over conventional catalysts.In this study,we proposed a universal synthetic strategy to construct heteroatom axially coordinated Fe–N_(4) single-atom seawater catalyst materials(Cl–Fe–N_(4) and S–Fe–N_(4)).X-ray absorption spectroscopy confirmed their five-coordinated square pyramidal structure.Systematic evaluation of catalytic activities revealed that compared with S–Fe–N_(4),Cl–Fe–N_(4) exhibits smaller electrochemical active surface area and specific surface area,yet demonstrates higher limiting current density(5.8 mA cm^(−2)).The assembled zinc-air batteries using Cl–Fe–N_(4) showed superior power density(187.7 mW cm^(−2) at 245.1 mA cm^(−2)),indicating that Cl axial coordination more effectively enhances the intrinsic ORR activity.Moreover,Cl–Fe–N_(4) demonstrates stronger Cl−poisoning resistance in seawater environments.Chronoamperometry tests and zinc-air battery cycling performance evaluations confirmed its enhanced stability.Density functional theory calculations revealed that the introduction of heteroatoms in the axial direction regulates the electron center of Fe single atom,leading to more active reaction intermediates and increased electron density of Fe single sites,thereby enhancing the reduction in adsorbed intermediates and hence the overall ORR catalytic activity.
基金supported by the Program for Guangdong Province Introduced Innovative and Entrepreneurial Team Program(2023ZT10L061)the NSFC Projects(Grant No.22402232)the Project supported by the Natural Science Foundation of Guangdong Province,China(Grant No.2025A1515011742).
文摘The development of atomically dispersed multi-metallic catalysts is imperative for tailoring catalytic performance and elucidating structure-activity relationships.However,synthesizing such precisely engineered architectures while maintaining atomic dispersion of distinct metal centers remains a formidable challenge due to thermodynamic instability and synthetic complexity.We herein propose a topological confinement pre-anchoring strategy via pre-anchoring spatially resolved Zn/Fe dual-metal sources in a structurally engineered metal-organic framework precursor to synthesize atomically dispersed ZnFe bimetallic single-atom catalysts.Extended X-ray absorption fine structure measurements and X-ray absorption near-edge structure reveal that the atomically dispersed Zn/Fe metal sites and electronic redistribution in ZnFe bimetallic single-atom catalysts.The ultrahigh surface area,hierarchical pore,and synergistic effect between Zn/Fe can greatly favor the exposure of the active site,mass transport,and improvement of intrinsic activity.Consequently,the ZnFe bimetallic single-atom catalyst demonstrates superior oxygen reduction reaction performance,achieving a half-wave potential of 0.86 V and delivering a kinetic current density of 10.1 mA cm^(-2)at 0.85 V versus RHE in 0.1 m KOH electrolyte.These metrics not only surpass those of commercial Pt/C,but also rival the highest-performing catalysts reported to date.The Zn-air battery built with ZnFe bimetallic single-atom catalyst exhibits high power density(278.5 mW cm^(-2))and specific discharging capacities(657 mAh g^(-1)).This work provides a new design pathway for constructing atomically dispersed multi-metal electrocatalysts for high-performance energy-related applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.22272105 and 22572118)Natural Science Foundation of Shanghai(Grant No.23ZR1423900)。
文摘Optimizing the oxygen reduction reaction(ORR)kinetics requires precise control of intermediate adsorption at active sites,which can be achieved through orbital engineering by regulating the electronic structure.This study addresses the challenge by exploring how modulation of the 3d-orbital electronic structure of FeN_(4) active sites influences ORR electrocatalysis.To realize this,a catalyst composed of Fe_(3)C nanoparticles and FeN_(4) single atoms anchored on carbon black(Fe_(3)C-FeN_(4)/CB)was synthesized via a synergistic strategy of spatial confinement and atmosphere control.This unique heterostructure creates interfaces between Fe_(3)C and FeN_(4) that modulate the electronic configuration of the FeN_(4) center,transforming its geometry from square-planar to quasi-octahedral.Spectroscopic characterizations and theoretical calculations reveal that this orbital modulation results in a downward shift of the Fe dband center,altering the reaction pathway and lowering the energy barrier for ORR.Consequently,the Fe_(3)C-FeN_(4)/CB catalyst exhibits outstanding ORR activity,four-electron selectivity,excellent methanol tolerance,and remarkable electrochemical stability.When applied in a zinc-air battery,it achieves a peak power density of 178.4 mW cm^(-2)and superior cycling stability compared to commercial Pt/C catalysts.This work provides valuable insights into heterointerface-induced orbital modulation as a promising design principle for high-performance ORR electrocatalysts.
基金part of the ALU-STORE project(Aluminum Metal as Energy Carrier for Seasonal Energy Storage)funded by the KIT Future Fieldsthe research performed at CELEST(Center for Electrochemical Energy Storage Ulm-Karlsruhe)+1 种基金funding from the German Federal Ministry of Research,Technology and Space(BMFTR)in the Nano Mat Futur program(03XP0423)basic funding from the Helmholtz Association。
文摘α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the performance ofα-MnO_(2) electrodes by systematically varying theα-MnO_(2)-to-Vulcan ratio within the catalyst layer.Electrodes are evaluated in a gas diffusion electrode(GDE)half-cell,where an optimized catalyst layer composition leads to significantly improved ORR performance.By finetuning both theα-MnO_(2)-to-Vulcan ratio and theα-MnO_(2) loading,the electrode outperforms a commercial MnO_(2)-based electrode and approaches the performance of the Pt/C benchmark.The improvement is attributed to the presence of a three-dimensional(3D)Vulcan network electronically connecting catalytically activeα-MnO_(2) sites with the substrate.Additionally,the optimized electrodes are employed in a prototype Al-O_(2) flow cell.Under constant oxygen flow,power densities exceed 250 mW cm^(-2),which is significantly higher than that of conventional Al-air batteries.Electrochemical impedance spectroscopy combined with distribution of relaxation times(DRT)analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode.The analysis reveals that the anode contributes more than twice as much impedance as the cathode,highlighting the need for further anode optimization.This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell.Subsequent measurements in an Al-O_(2) flow cell validate the approach.The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.
基金supported by the National Natural Science Foundation of China(No.21571062)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning to JGL,and the Fundamental Research Funds for the Central Universities(No.222201717003)。
文摘Exploiting non-precious metal catalysts with excellent oxygen reduction reaction(ORR)performance for energy devices is paramount essential for the green and sustainable society development.Herein,low-cost,high-performance biomass-derived ORR catalysts with an asymmetric Fe-N_(3)P configuration was prepared by a simple pyrolysis-etching technique,where carboxymethyl cellulose(CMC)was used as the carbon source,urea and 1,10-phenanthroline iron complex(FePhen)as additives,and Na_(3)PO_(4)as the phosphorus dopant and a pore-forming agent.The CMC-derived FeNPC catalyst displayed a large specific area(BET:1235 m^(2)g^(-1))with atomically dispersed Fe-N_(3)P active sites,which exhibited superior ORR activity and stability in alkaline solution(E_(1/2)=0.90 V vs.RHE)and Zn-air batteries(P_(max)=149 mW cm^(-2))to commercial Pt/C catalyst(E_(1/2)=0.87 V,P_(max)=118 mW cm^(-2))under similar experimental conditions.This work provides a feasible and costeffective route toward highly efficient ORR catalysts and their application to Zn-air batteries for energy conversion.
基金supported by the National Natural Science Foundation of China(No.22208322)the Natural Science Foundation of Henan(No.242300421230)+1 种基金the Key Research Projects of Higher Education Institutions of Henan Province(No.24A530009)the Special Fund for Young Teachers from Zhengzhou University(No.JC23257011).
文摘Designing advanced electrocatalysts with high methanol tolerance in the oxygen reduction reaction process is crucial for the sustainable implementation of direct methanol fuel cells.Herein,we present a Pt/C catalyst modified with black phosphorus(BP)nanodots(BPNDs-Pt/C)by using a facile ultrasonic mixing method.Experimental and computational investigations reveal that the electron transfer from BP to Pt leads to weak adsorption of hydroxyl groups on the Pt surface.As a result,the BPNDs-Pt/C catalyst exhibits efficient activity and anti-methanol ability for cathodic oxygen reduction electrocatalysis in an acidic medium.Additionally,it demonstrates high activity for oxygen reduction reaction(ORR)in an alternative alkaline system with cation exchange membrane and eliminable methanol penetration.This work highlights the feasibility of using non-metallic elements to regulate the electronic structure and surface properties of Pt-based nanomaterials.Furthermore,the designed BPNDs-Pt/C electrocatalyst,with controllable ORR performance,can be applied across various scenarios based on demand.
基金supported by the National Natural Science Foundation of China(Nos.22272105 and 22002110)Natural Science Foundation of Shanghai(No.23ZR1423900)。
文摘Nitrogen-doping of carbon support(N-C)for platinum(Pt)nanoparticles to form Pt/N-C catalyst represents an effective strategy to promote the electrocatalysis of cathodic oxygen reduction reaction(ORR)in proton exchange membrane fuel cells.For fundamental understanding,clearly identifying the metalsupport effect on enhancement mechanisms of ORR electrocatalysis is definitely needed.In this work,the impact of Pt-support interaction via interfacial Pt-N coordination on electrocatalytic ORR activity and stability in Pt/N-C catalyst is deeply studied through structural/compositional characterizations,electrochemical measurements and theoretical DFT-calculations/AIMD-simulations.The resulting Pt/N-C catalyst exhibits a superior electrocatalytic performance compared to the commercial Pt/C catalyst in both half-cell and H_(2)-O_(2)fuel cell.Experimental and theoretical results reveal that the interfacial Pt-N coordination enables electron transfer from N-C support to Pt nanoparticles,which can weaken the adsorption strength of oxygen intermediates on Pt surface to improve ORR activity and induce the strong Pt-support interaction to enhance electrochemical stability.
基金financially supported by the National Natu-ral Science Foundation of China(Nos.21805052 and 22227804)the Guangdong Basic and Applied Basic Research Foundation(No.2023B1515020110)+4 种基金the Science and Technology Research Project of Guangzhou(Nos.202102020787 and 2023A03J0030)the De-partment of Science&Technology of Guangdong Province(No.2022A156)the Key Laboratory of Optoelectronic Materials and Sensors in Guangdong Provincial Universities(No.2023KSYS008)the Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.20225546)the College Student Innovation and Entrepreneurship Training Program of Guangzhou University(No.XJ202311078029).
文摘Selective electrocatalysis of two-electron oxygen reduction reaction(2e^(-)ORR)has been recognized as a sustainable and on-site process for hydrogen peroxide(H_(2)O_(2))production.Great progress has been achieved for 2e^(-)ORR in alkaline media.However,it is challenged by insufficient activity and selectiv-ity of the catalysts in acidic electrolytes.Herein,we report sulfur-poisoned PtNi/C catalysts(PtNiSx/C)that could regulate ORR from the 4e^(-)to 2e^(-)pathway.The identified PtNiS0.6/C offers high activity in terms of onset potential of∼0.69 V(vs.RHE)and∼80%selectivity.The mass activity is also compara-ble and outperforms representative Pt-based precious and transition-metal-based catalysts.In addition,it is interestingly found that the Faradaic efficiency further increased to 95%during the long-term elec-trolysis test due to Ni atom surface migration.The electrochemical production of the H_(2)O_(2)system was applied to the electro-Fenton process,which has realized the effective degradation of organic pollutants.This work offers a strategy by sulfur poisoning PtNi/C catalyst to realize Pt-based 2e^(-)ORR active catalysts to electrolysis of H_(2)O_(2)in acidic media.
基金supported by the National Key R&D Program of China (2021YFF0500504)National Natural Science Foundation of China (No. 51976169)the financial supports from the Fundamental Research Funds for the Central Universities。
文摘The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel cells.Herein,we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dualmetal sites on N-doped carbon(denoted(FeMn-DA)-N-C)for both anion-exchange membrane fuel cells(AEMFC)and proton exchange membrane fuel cells(PEMFC).The(FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N_(4)and Mn-N_(4)sites on the carbon surface,yielded via a facile doping-adsorption-pyrolysis route.The introduction of Mn carries several advantageous attributes:increasing the number of active sites,effectively anchoring Fe due to effective electron transfer to Mn(revealed by X-ray absorption spectroscopy and density-functional theory(DFT),thus preventing the aggregation of Fe),and effectively circumventing the occurrence of Fenton reaction,thus reducing the consumption of Fe.The(FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1 M KOH and 0.1 M HClO_(4),respectively,as well as outstanding stability.As manifested by DFT calculations,the introduction of Mn affects the electronic structure of Fe,down-shifts the d-band Fe active center,accelerates the desorption of OH groups,and creates higher limiting potentials.The AEMFC and PEMFC with(FeMn-DA)-N-C as the cathode catalyst display high power densities of 1060 and 746 mW cm^(-2),respectively,underscoring their promising potential for practical applications.Our study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.
基金Project supported by the National Natural Science Foundation of China(22062019)the Natural Science Foundation of Inner Mongolia of China(2022QN02002)Science and Technology Program of Inner Mongolia Autonomous Region,China(2020PT0003)。
文摘The development of an e fficacious and easily prepared no nprecious metal electrocatalyst is crucial for the oxygen reduction reaction(ORR).This work used a dual template method to prepare the amorphous rare earth-based catalyst PrO_(x)-NC,and optimized the calcination temperature and proportion.The PrO_(x)-NC-900 catalyst has high durability and activity and exhibits superior ORR performance in alkaline electrolytes with an onset potential(E_(0))of 0.96 V and a half-wave potential(E_(1/2))of 0.85 V.The research results indicate that the ORR performance of rare earth oxide composite carbon catalysts can be improved by adjusting oxygen vacancies(Ov).In addition,high specific surface area,N rich defect carbon.increased oxygen vacancies,and the synergistic effect of oxygen vacancies and N-doped carbon interfacial layer play a significant part in the enhancement of ORR.The performance of the zinc air battery assembled with PrO_(x)-NC-900 is significantly improved,and rare earth oxides and carbon frameworks originating from metal organic frameworks(MOFs)contribute to the oxygen electrocatalyst and electron transfer rate of the zinc air battery.This catalyst provides promising information for the development of rare earth metal oxide nanostructures as potential candidate materials for ORR in alkaline media.
基金supported by the National Natural Science Foundation(22279036)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003).
文摘Alloying transition metals with Pt is an effective strategy for optimizing Pt-based catalysts toward the oxygen reduction reaction(ORR).Atomic ordered intermetallic compounds(IMC)provide unique electronic and geometrical effects as well as stronger intermetallic interactions due to the ordered arrangement of metal atoms,thus exhibiting superior electrocata-lytic activity and durability.However,quantitatively analyzing the ordering degree of IMC and exploring the correlation between the ordering degree and ORR activity remains extremely challenging.Herein,a series of ternary Pt_(2)NiCo interme-tallic catalysts(o-Pt_(2)NiCo)with different ordering degree were synthesized by annealing temperature modulation.Among them,the o-Pt_(2)NiCo which annealed at 800℃for two hours exhibits the highest ordering degree and the optimal ORR ac-tivity,which the mass activity of o-Pt_(2)NiCo is 1.8 times and 2.8 times higher than that of disordered Pt_(2)NiCo alloy and Pt/C.Furthermore,the o-Pt_(2)NiCo still maintains 70.8%mass activity after 30,000 potential cycles.Additionally,the ORR activity test results for Pt_(2)NiCo IMC with different ordering degree also provide a positive correlation between the ordering degree and ORR activity.This work provides a prospective design direction for ternary Pt-based electrocatalysts.
基金the financial support from the National Natural Science Foundation of China(No.22178307)China Southern Power Grid(Grant Nos.0470002022030103HX00002-01).
文摘The poor electronic conductivity of metal-organic framework(MOF)materials hinders their direct application in the field of electrocatalysis in fuel cells.Herein,we proposed a strategy of embedding carbon nanotubes(CNTs)during the growth process of MOF crystals,synthesizing a metalloporphyrin-based MOF catalyst TCPPCo-MOF-CNT with a unique CNT-intercalated MOF structure.Physical characterization revealed that the CNTs enhance the overall conductivity while retaining the original characteristics of the MOF and metalloporphyrin.Simultaneously,the insertion of CNTs generated adequate mesopores and created a hierarchical porous structure that enhances mass transfer efficiency.X-ray photoelectron spectroscopic analysis confirmed that the C atom in CNT changed the electron cloud density on the catalytic active center Co,optimizing the electronic structure.Consequently,the E_(1/2) of the TCPPCo-MOF-CNT catalyst under neutral conditions reached 0.77 V(vs.RHE),outperforming the catalyst without CNTs.When the TCPPCo-MOF-CNT was employed as the cathode catalyst in assembling microbial fuel cells(MFCs)with Nafion-117 as the proton exchange membrane,the maxi-mum power density of MFCs reached approximately 500 mW·m^(-2).
基金the National Key Research and Development Program of China(2022YFB4004100)National Natural Science Foundation of China(22272161,22179126)+1 种基金the Jilin Province Science and Technology Development Program(YDZJ202202CXJD011,20240101019JC)Jilin Province major science and technology project(222648GX0105103875)for financial supports.
文摘The weak adsorption energy of oxygen-containing intermediates on Co center leads to a considerable performance dis-parity between Co-N-C and costly Pt benchmark in catalyzing oxygen reduction reaction(ORR).In this work,we strategi-cally engineer the active site structure of Co-N-C via B substitution,which is accomplished by the pyrolysis of ammonium borate.During this process,the in-situ generated NH_(3)gas plays a critical role in creating surface defects and boron atoms substituting nitrogen atoms in the carbon structure.The well-designed CoB_(1)N_(3)active site endows Co with higher charge density and stronger adsorption energy toward oxygen species,potentially accelerating ORR kinetics.As expected,the resulting Co-B/N-C catalyst exhibited superior ORR performance over Co-N-C counterpart,with 40 mV,and fivefold en-hancement in half-wave potential and turnover frequency(TOF).More importantly,the excellent ORR performance could be translated into membrane electrode assembly(MEA)in a fuel cell test,delivering an impressive peak power density of 824 mW·cm^(-2),which is currently the best among Co-based catalysts under the same conditions.This work not only demon-strates an effective method for designing advanced catalysts,but also affords a highly promising non-precious metal ORR electrocatalyst for fuel cell applications.
基金supported by the National Natural Science Foundation of China(52164028,52274297)the Start-up Research Foundation of Hainan University(KYQD(ZR)20008,KYQD(ZR)21125,KYQD(ZR)23169))+1 种基金Collaborative Innovation Center of Marine Science and Technology of Hainan University(XTCX2022HYC14)Innovative Research Project for Postgraduate Students in Hainan Province(Qhyb2024-95).
文摘Development of robust electrocatalyst for oxygen reduction reaction(ORR)in a seawater electrolyte is the key to realize seawater electrolyte-based zinc-air batteries(SZABs).Herein,constructing a local electric field coupled with chloride ions(Cl-)fixation strategy in dual single-atom catalysts(DSACs)was proposed,and the resultant catalyst delivered considerable ORR performance in a seawater electrolyte,with a high half-wave potential(E_(1/2))of 0.868 V and a good maximum power density(Pmax)of 182 mW·cm^(−2)in the assembled SZABs,much higher than those of the Pt/C catalyst(E_(1/2):0.846 V;Pmax:150 mW·cm^(−2)).The in-situ characterization and theoretical calculations revealed that the Fe sites have a higher Cl^(−)adsorption affinity than the Co sites,and preferentially adsorbs Cl^(−)in a seawater electrolyte during the ORR process,and thus constructs a low-concentration Cl^(−)local microenvironment through the common-ion exclusion effect,which prevents Cl^(−)adsorption and corrosion in the Co active centers,achieving impressive catalytic stability.In addition,the directional charge movement between Fe and Co atomic pairs establishes a local electric field,optimizing the adsorption energy of Co sites for oxygen-containing intermediates,and further improving the ORR activity.
