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
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
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
The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these c...The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.展开更多
The high conductivity of electrocatalyst can eliminate the Schottky energy barrier at the interface of heterogeneous phases during an electrocatalytic reaction and accelerate the rapid electron transfer to the catalyt...The high conductivity of electrocatalyst can eliminate the Schottky energy barrier at the interface of heterogeneous phases during an electrocatalytic reaction and accelerate the rapid electron transfer to the catalytic active center.Therefore,the electronic conductivity is a vital parameter for oxygen reduction reaction(ORR).Covalent triazine frameworks(CTFs)have shown great potential application as electrocatalysts in ORR with a merit of the diverse building blocks.However,the intrinsic low conductivity and high impedance of CTFs could be significant setbacks in electrocatalytic application.Herein,CTFs were constructed by introducing F and N co-modification for efficient 2e^(-)ORR.Compared with the pristine CTF,the co-presence of F,N could increase the conductivity obviously by 1000-fold.As a result,F-N-CTF exhibits enhanced catalytic performance of H_(2)O_(2)generation and selectivity towards reaction pathways.This work reveals the importance of conductivity optimization for CTFs and provides guidance for designing high conductivity non-metallic organic semiconductor catalysts for 2e^(-)ORR.展开更多
The main challenge preventing the broad commercial use of polymer electrolyte membrane fuel cells(PEMFCs)is the dependence on noble metals,specifically electrocatalyst(EC)based on platinum(Pt)at the cathode,which is i...The main challenge preventing the broad commercial use of polymer electrolyte membrane fuel cells(PEMFCs)is the dependence on noble metals,specifically electrocatalyst(EC)based on platinum(Pt)at the cathode,which is indispensable for assisting the oxygen reduction reaction(ORR)in fuel cells(FCs).Research on EC-containing non-noble metal(NNM)has been considerable over the past few decades to minimize costs and reduce the excessive loading of EC based on Pt.This review is aimed at improving the reliability and stability of non-precious metal EC.To achieve a feasible ORR,Pt-based EC is crucial for the widespread commercial applications of PEMFCs.The review emphasizes improving ORR performance,stability,and cost-effectiveness in catalysts that are not precious metals.The article examines the advancements in non-precious nanomaterial-based EC,highlighting different types that have improved ORR efficiency.The review suggests future possibilities and directions for further improvement in designing and constructing EC with high efficiency and low costs for PEMFCs.展开更多
Single-atom catalysts(SACs)are promising for oxygen reduction reaction(ORR)on account of their excellent catalytic activity and maximum utilization of atoms.However,due to the complicated preparation processes and exp...Single-atom catalysts(SACs)are promising for oxygen reduction reaction(ORR)on account of their excellent catalytic activity and maximum utilization of atoms.However,due to the complicated preparation processes and expensive reagents used,the cost of SACs is usually too high to put into practical application.The development of cost-effective and sustainable SACs remains a great challenge.Herein,a low-cost method employing biomass is designed to prepare efficient single-atom Fe-N-C catalysts(SA-Fe-N-C).Benefiting from the confinement effect of porous carbon support and the coordination effect of glucose,SA-Fe-N-C is derived from cheap flour by the two-step pyrolysis.Atomically dispersed Fe atoms exist in the form of Fe-N_(x),which acts as active sites for ORR.The catalyst shows outstanding activity with a half-wave potential(E_(1/2))of 0.86 V,which is better than that of Pt/C(0.84 V).Additionally,the catalyst also exhibits superior stability.The ORR catalyzed by SA-Fe-N-C proceeds via an efficient 4e transfer pathway.The high performance of SA-Fe-N-C also benefits from its porous structure,extremely high specific surface area(1450.1 m^(2)/g),and abundant micropores,which are conducive to increasing the density of active sites and fully exposing them.This work provides a cost-effective strategy to synthesize SACs from cheap biomass,achieving a balance between performance and cost.展开更多
Developing high performance electrocatalysts for the cathodic oxygen reduction reaction(ORR)is essential for the widespread application of fuel cells.Herein,a promising Pt_(2)NiCo atomic ordered ternary intermetallic ...Developing high performance electrocatalysts for the cathodic oxygen reduction reaction(ORR)is essential for the widespread application of fuel cells.Herein,a promising Pt_(2)NiCo atomic ordered ternary intermetallic compound with N-doped carbon layer coating(o-Pt_(2)NiCo@NC)has been synthesized via a facile method and applied in acidic ORR.The confinement effect provided by the carbon layer not only inhibits the agglomeration and sintering of intermetallic nanoparticles during high temperature process but also provides adequate protection for the nanoparticles,mitigating the aggregation,detachment and poisoning of nanoparticles during the electrochemical process.As a result,the o-Pt_(2)NiCo@NC demonstrates a mass activity(MA)and specific activity(SA)of 0.65 A/mgPt and 1.41mA/cm_(Pt) ^(2) in 0.1mol/L HClO_(4),respectively.In addition,after 30,000 potential cycles from 0.6 V to 1.0 V,the MA of o-Pt_(2)NiCo@NC shows much lower decrease than the disordered Pt_(2)NiCo alloy and Pt/C.Even cycling at high potential cycles of 1.5 V for 10,000 cycles,the MA still retains∼70%,demonstrating superior long-term durability.Furthermore,the o-Pt_(2)NiCo@NC also exhibits strong tolerance to CO,SO_(x),and PO_(x) molecules in toxicity tolerance tests.The strategy in this work provides a novel insight for the development of ORR catalysts with high catalytic activity,durability and toxicity tolerance.展开更多
Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degrada...Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degradation hinder practical implementation.Herein,we fabricate a Ru-Fe dual-site catalyst(RuFe-N-C)through a two-step pyrolysis strategy.Structural characterization reveals atomic-scale proximity between Ru single atoms and Fe-N_(4) moieties,exhibiting a projected distance of~1.7Å.This configuration induces Fe–N bond elongation accompanied by 2.5%lattice distortion.The optimized RuFe-N-C catalyst exhibits high ORR performance,with a half-wave potential(E_(1/2))of 0.840 V and peak power density(P_(max))of 938 mW cm^(-2) under 150 kPa absolute H_(2)-O_(2).These metrics signify substantial enhancements relative to conventional Fe-N-C benchmarks(+21 mV in E_(1/2) and+42%in P_(max)).Moreover,the catalyst maintains outstanding stability,showing merely 17 mV E_(1/2) decay after 10000 accelerated durability test(ADT)cycles.Experimental analyses reveal a bifunctional mechanism:(1)Adjacent Ru sites substantially enhance the intrinsic ORR activity of Fe-N_(4) moieties,delivering a notable turnover frequency(TOF=17.86 e site^(-1) s^(-1) at 0.85 V vs.RHE)that exceeds state-of-the-art Fe-N-C benchmarks by 1-2 orders of magnitude(<1 e site^(-1) s^(-1));(2)Ru centers function as electron relays that facilitate ROS scavenging,thus suppressing degradation.This work establishes a paradigm for engineering bimetallic single-atom catalysts through synergistic electronic modulation to concurrently enhance activity and stability.展开更多
Transition metal-nitrogen-carbon(M-N-C)with 3d transition metals as noble metal-free catalyzing oxygen reduction reaction(ORR)electrocatalysts still face critical challenges in activity and durability due to the Fento...Transition metal-nitrogen-carbon(M-N-C)with 3d transition metals as noble metal-free catalyzing oxygen reduction reaction(ORR)electrocatalysts still face critical challenges in activity and durability due to the Fenton effect associated with these metals in practical application.To tackle the issue,herein,we report Fenton-inactive rare earth metal La-N-C with dual active sites for efficient ORR,which was synthesized by pyrolyzing a mixed complexing compound of 1,10-phenanthroline as ligand with LaCl_(3)and MgCl_(2)as an activation agent.The as-synthesized La-N-C features an abundant microporous structure with atomically dispersed LaN_(4)O moieties as new active sites,exhibiting outstanding ORR performance.Its half-wave potentials are 0.92 and 0.76 V in 0.1 M KOH and 0.5 M H_(2)SO_(4)respectively,and only a 10 mV half-wave potential loss after 50 K cycles in 0.1 M KOH,achieving the highest level of current non-3d M-N-C ORR electrocatalysts.Meanwhile,the ORR activity is further validated by efficient performance with a power density output of 211 and 480 mW cm^(-2)on a single Zn-air battery and proton exchange membrane fuel cell respectively.Furthermore,theoretical calculations confirm that the unique LaN_(4)O moiety adjacent to the microspore vacancy with graphitic N dopant not only presents a negative shift of the La 5d orbitals,significantly lowering the adsorption energy of*OOH in ORR,but also induces the carbon atom near the graphitic N as one more active site for ORR.This work highlights the potential application of La-N-C as an efficient ORR catalyst in green energy conversion devices.展开更多
In this paper,we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon(ZnNC)via a green aqueous impregnation method followed by a two-s...In this paper,we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon(ZnNC)via a green aqueous impregnation method followed by a two-step annealing protocol(H_(2)/Ar,600 and 800℃)to circumvent the sintering issues imposed by conventional thermodynamics.Physical characterizations(X-ray diffraction,high-angle annular dark-field scanning transmission electron microscopy,X-ray absorption spectroscopy)and theoretical calculations reveal that low-temperature annealing at 600℃stabilizes sub-nano disordered PtFe alloys via the strong metal-support interactions(SMSI)between Zn in ZnNC and Pt precursors,while high-temperature treatment at 800℃promotes Zn diffusion from the support into the alloy bulk and simultaneously triggers the disorder-to-order phase transition.The as-prepared ZnNC-15PtFeZn exhibits an initial mass activity of 0.769 mA/μgPt and retains 61.7%of its activity after 30000 cycles of accelerated stress testing(AST).Notably,when used as a cathode catalyst in MEA,ZnNC-15PtFeZn achieves superior power density(2.018 W/cm^(2)under H_(2)-O_(2))at half the Pt loading(0.05 mg/cm^(2))of state-of-the-art commercial Pt/C,highlighting its potential for low-Pt PEMFCs.Density functional theory confirms that Fe enhances ORR activity via ligand effects,while Zn strengthens Pt-Fe/Zn bonding(elevating vacancy formation energies),thereby improving structural stability.This mild,scalable aqueous impregnation strategy offers a general approach for synthesizing multi-component ordered alloys in electrocatalysis.展开更多
Proton exchange membrane fuel cells have been identified as a potentially valuable technology for the efficient conversion of hydrogen energy into electrical energy.Nevertheless,one significant constraint on the perfo...Proton exchange membrane fuel cells have been identified as a potentially valuable technology for the efficient conversion of hydrogen energy into electrical energy.Nevertheless,one significant constraint on the performance of fuel cells is the oxygen reduction reaction(ORR).It is meaningful to progress the development of representative ORR electrocatalysts.In recent times,there has been an intensified focus on single-atom catalysts(SACs)due to the advantages of homogeneous distribution and high atom utilization efficiency.In particular,the coordination structure of metal sites plays an important role in the electrochemical performance of SACs.However,the relationship between coordination structures and catalytic performance remains unclear.In this review,we summarized the research progress on SACs in electrocatalytic ORR in recent years.Then the structure-activity relationship in the symmetric and asymmetric coordination structures of SACs was clarified.We further proposed rational design principles for regulating the coordination structure of SACs.Finally,the opportunities and challenges were discussed.展开更多
Regulating the electronic structure and oxygencontaining intermediates adsorption behavior on Fe-based catalysts is of great significance to cope with the sluggish oxygen reduction reaction(ORR)kinetics,but it still r...Regulating the electronic structure and oxygencontaining intermediates adsorption behavior on Fe-based catalysts is of great significance to cope with the sluggish oxygen reduction reaction(ORR)kinetics,but it still remains a great challenge.In this work,Fe atom clusters(Fe_(AC))modified by high-density Cu single atoms(Cu_(SA))in a N,S-doped porous carbon substrate(Fe_(AC)/Cu_(SA)@NCS)is reported for enhanced ORR electrocatalysis.Fe_(AC)/Cu_(SA)@NCS exhibits excellent ORR performance with a half-wave potential(E_(1/2))of 0.911 V,a high four-electron process selectivity and excellent stability.The ORR performance is also verified in the Fe_(AC)/Cu_(SA)@NCS-based Zn-air battery,which shows a high peak power density of 192.67 mW cm^(-2),a higher specific capacity of 808.3 mAh g^(-1)and impressive charge-discharge cycle stability.Moreover,density functional theory calculations show that Cu single atoms synergistically modulate the electronic structure Fe active atoms in Fe atomic clusters,reducing the energy barrier of the rate-determining step(i.e.,*OH desorption)on Fe_(AC)/Cu_(SA)@NCS.This work provides an effective way to regulate the electronic structure of Fe-based catalysts and optimize their electrocatalytic activity based on the introduction of a second metal source.展开更多
Efficient electrocatalysts for oxygen reduction reaction(ORR)show significant importance for advancing the performance and affordability of proton exchange membrane fuel cells and other energy conversion devices.Herei...Efficient electrocatalysts for oxygen reduction reaction(ORR)show significant importance for advancing the performance and affordability of proton exchange membrane fuel cells and other energy conversion devices.Herein,PtCo_(3)nanoalloys dispersed on a carbon black support,were prepared using ultrafast Joule heating method.By tuning the heating modes,such as high-temperature shock and heating for 2 s,two kinds of PtCo_(3)nanoalloys with varying crystallinities were obtained,referred to as PtCo_(3)-HTS(average size of 5.4 nm)and PtCo_(3)-HT-2 s(average size of 6.4 nm),respectively.Impressively,PtCo_(3)-HTS exhibited superior electrocatalytic ORR activity and stability(E_(1/2)=0.897 V vs.RHE and 36mV negative shift after 50,000 cycles),outperforming PtCo_(3)-HT-2 s(E_(1/2)=0.872 V and 16.2mV negative shift),as well as the commercial Pt/C(20 wt%)catalyst(E_(1/2)=0.847 V and 21.0mV negative shift).The enhanced ORR performance of PtCo_(3)-HTS may be attributed to its low crystallinity,which results in an active local electronic structure and chemical state,as confirmed by X-ray diffraction(XRD)and X-ray absorption fine structure(XAFS)analyses.The ultrafast Joule heating method showed great potential for crystallinity engineering,offering a promising pathway to revolutionize the manufacturing of cost-effective and environmentally friendly catalysts for clean energy applications.展开更多
Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping...Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.展开更多
Hydrogen peroxide(H_(2)O_(2))electrosynthesis via two-electron oxygen reduction reaction(2e-ORR)is a promising alternative for the energy-intensive anthraquinone process.However,the instability of the catalytic metal ...Hydrogen peroxide(H_(2)O_(2))electrosynthesis via two-electron oxygen reduction reaction(2e-ORR)is a promising alternative for the energy-intensive anthraquinone process.However,the instability of the catalytic metal sites in the state-of-the-art metal single-atom catalysts(M-SACs)hinders their further industrial applications,and the high potential and valueless oxygen product of the conventional anodic oxygen evolution reaction(OER)further limit the economic efficiency of this technology.To address this,a dynamically local structure reconstruction strategy is proposed to in situ transfer the active sites from unstable metal sites to the stable surrounding carbon sites for efficient and durable 2e^(-)ORR electrocatalysis.For the as-designed Mn-N_(3)O-C catalyst,by reconstructing Mn sites into Mn(^(*)OH),the Mn sites were passivated and carbon sites adjacent to the O atom were verified to be the actual active sites by in situ characterization and theoretical calculation.Consequently,Mn-N_(3)O-C exhibited>80%Faradaic efficiency and superior long-term durability over 100 h for H_(2)O_(2)electrosynthesis at~120 mA cm^(-2).In addition,coupling anodic ethylene glycol oxidation reaction(EGOR)further improves the efficiency and economic viability of the H_(2)O_(2)electrosynthesis system.This two-pronged strategy thus opens up a new opportunity for the development of stable H_(2)O_(2)electrosynthesis with low energy consumption and superior economic performance.展开更多
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(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.
基金supported by Shanxi Province Science Foundation for Youths(202203021212300)Taiyuan University of Science and Technology Scientific Research Initial Funding(20212064)Outstanding Doctoral Award Fund in Shanxi Province(20222060).
文摘The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.
基金the financial support by the National Natural Science Foundation of China(Nos.22205124,52172206)Natural Science Foundation of Shandong province(Nos.ZR2021QB070,ZR2023QB110)+2 种基金Basic Research Projects for the Pilot Project of Integrating Science and Education and Industry of Qilu University of Technology(Shandong Academy of Sciences)(Nos.2023PY024,2023PX108)Special Fund for Taishan Scholars Projectthe Development Plan of Youth Innovation Team in Colleges and Universities of Shandong Province。
文摘The high conductivity of electrocatalyst can eliminate the Schottky energy barrier at the interface of heterogeneous phases during an electrocatalytic reaction and accelerate the rapid electron transfer to the catalytic active center.Therefore,the electronic conductivity is a vital parameter for oxygen reduction reaction(ORR).Covalent triazine frameworks(CTFs)have shown great potential application as electrocatalysts in ORR with a merit of the diverse building blocks.However,the intrinsic low conductivity and high impedance of CTFs could be significant setbacks in electrocatalytic application.Herein,CTFs were constructed by introducing F and N co-modification for efficient 2e^(-)ORR.Compared with the pristine CTF,the co-presence of F,N could increase the conductivity obviously by 1000-fold.As a result,F-N-CTF exhibits enhanced catalytic performance of H_(2)O_(2)generation and selectivity towards reaction pathways.This work reveals the importance of conductivity optimization for CTFs and provides guidance for designing high conductivity non-metallic organic semiconductor catalysts for 2e^(-)ORR.
文摘The main challenge preventing the broad commercial use of polymer electrolyte membrane fuel cells(PEMFCs)is the dependence on noble metals,specifically electrocatalyst(EC)based on platinum(Pt)at the cathode,which is indispensable for assisting the oxygen reduction reaction(ORR)in fuel cells(FCs).Research on EC-containing non-noble metal(NNM)has been considerable over the past few decades to minimize costs and reduce the excessive loading of EC based on Pt.This review is aimed at improving the reliability and stability of non-precious metal EC.To achieve a feasible ORR,Pt-based EC is crucial for the widespread commercial applications of PEMFCs.The review emphasizes improving ORR performance,stability,and cost-effectiveness in catalysts that are not precious metals.The article examines the advancements in non-precious nanomaterial-based EC,highlighting different types that have improved ORR efficiency.The review suggests future possibilities and directions for further improvement in designing and constructing EC with high efficiency and low costs for PEMFCs.
基金Project(52174338)supported by the National Natural Science Foundation of ChinaProjects(2022JJ20086,2021JJ30796)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(2023CXQD005)supported by the Central South University Innovation-Driven Research Programme,ChinaProject(23B0841)supported by the Education Department of Hunan Provincial Government,China。
文摘Single-atom catalysts(SACs)are promising for oxygen reduction reaction(ORR)on account of their excellent catalytic activity and maximum utilization of atoms.However,due to the complicated preparation processes and expensive reagents used,the cost of SACs is usually too high to put into practical application.The development of cost-effective and sustainable SACs remains a great challenge.Herein,a low-cost method employing biomass is designed to prepare efficient single-atom Fe-N-C catalysts(SA-Fe-N-C).Benefiting from the confinement effect of porous carbon support and the coordination effect of glucose,SA-Fe-N-C is derived from cheap flour by the two-step pyrolysis.Atomically dispersed Fe atoms exist in the form of Fe-N_(x),which acts as active sites for ORR.The catalyst shows outstanding activity with a half-wave potential(E_(1/2))of 0.86 V,which is better than that of Pt/C(0.84 V).Additionally,the catalyst also exhibits superior stability.The ORR catalyzed by SA-Fe-N-C proceeds via an efficient 4e transfer pathway.The high performance of SA-Fe-N-C also benefits from its porous structure,extremely high specific surface area(1450.1 m^(2)/g),and abundant micropores,which are conducive to increasing the density of active sites and fully exposing them.This work provides a cost-effective strategy to synthesize SACs from cheap biomass,achieving a balance between performance and cost.
基金supported by the National Natural Science Foundation(No.22279036)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003).
文摘Developing high performance electrocatalysts for the cathodic oxygen reduction reaction(ORR)is essential for the widespread application of fuel cells.Herein,a promising Pt_(2)NiCo atomic ordered ternary intermetallic compound with N-doped carbon layer coating(o-Pt_(2)NiCo@NC)has been synthesized via a facile method and applied in acidic ORR.The confinement effect provided by the carbon layer not only inhibits the agglomeration and sintering of intermetallic nanoparticles during high temperature process but also provides adequate protection for the nanoparticles,mitigating the aggregation,detachment and poisoning of nanoparticles during the electrochemical process.As a result,the o-Pt_(2)NiCo@NC demonstrates a mass activity(MA)and specific activity(SA)of 0.65 A/mgPt and 1.41mA/cm_(Pt) ^(2) in 0.1mol/L HClO_(4),respectively.In addition,after 30,000 potential cycles from 0.6 V to 1.0 V,the MA of o-Pt_(2)NiCo@NC shows much lower decrease than the disordered Pt_(2)NiCo alloy and Pt/C.Even cycling at high potential cycles of 1.5 V for 10,000 cycles,the MA still retains∼70%,demonstrating superior long-term durability.Furthermore,the o-Pt_(2)NiCo@NC also exhibits strong tolerance to CO,SO_(x),and PO_(x) molecules in toxicity tolerance tests.The strategy in this work provides a novel insight for the development of ORR catalysts with high catalytic activity,durability and toxicity tolerance.
文摘Fe-N-C catalysts are promising substitutes for precious-metal platinum in acidic oxygen reduction reactions(ORR),yet their moderate intrinsic activity and susceptibility to reactive oxygen species(ROS)-induced degradation hinder practical implementation.Herein,we fabricate a Ru-Fe dual-site catalyst(RuFe-N-C)through a two-step pyrolysis strategy.Structural characterization reveals atomic-scale proximity between Ru single atoms and Fe-N_(4) moieties,exhibiting a projected distance of~1.7Å.This configuration induces Fe–N bond elongation accompanied by 2.5%lattice distortion.The optimized RuFe-N-C catalyst exhibits high ORR performance,with a half-wave potential(E_(1/2))of 0.840 V and peak power density(P_(max))of 938 mW cm^(-2) under 150 kPa absolute H_(2)-O_(2).These metrics signify substantial enhancements relative to conventional Fe-N-C benchmarks(+21 mV in E_(1/2) and+42%in P_(max)).Moreover,the catalyst maintains outstanding stability,showing merely 17 mV E_(1/2) decay after 10000 accelerated durability test(ADT)cycles.Experimental analyses reveal a bifunctional mechanism:(1)Adjacent Ru sites substantially enhance the intrinsic ORR activity of Fe-N_(4) moieties,delivering a notable turnover frequency(TOF=17.86 e site^(-1) s^(-1) at 0.85 V vs.RHE)that exceeds state-of-the-art Fe-N-C benchmarks by 1-2 orders of magnitude(<1 e site^(-1) s^(-1));(2)Ru centers function as electron relays that facilitate ROS scavenging,thus suppressing degradation.This work establishes a paradigm for engineering bimetallic single-atom catalysts through synergistic electronic modulation to concurrently enhance activity and stability.
基金financially supported by the National Natural Science Foundation of China(22075055)the Guangxi Science and Technology Project(AB16380030)。
文摘Transition metal-nitrogen-carbon(M-N-C)with 3d transition metals as noble metal-free catalyzing oxygen reduction reaction(ORR)electrocatalysts still face critical challenges in activity and durability due to the Fenton effect associated with these metals in practical application.To tackle the issue,herein,we report Fenton-inactive rare earth metal La-N-C with dual active sites for efficient ORR,which was synthesized by pyrolyzing a mixed complexing compound of 1,10-phenanthroline as ligand with LaCl_(3)and MgCl_(2)as an activation agent.The as-synthesized La-N-C features an abundant microporous structure with atomically dispersed LaN_(4)O moieties as new active sites,exhibiting outstanding ORR performance.Its half-wave potentials are 0.92 and 0.76 V in 0.1 M KOH and 0.5 M H_(2)SO_(4)respectively,and only a 10 mV half-wave potential loss after 50 K cycles in 0.1 M KOH,achieving the highest level of current non-3d M-N-C ORR electrocatalysts.Meanwhile,the ORR activity is further validated by efficient performance with a power density output of 211 and 480 mW cm^(-2)on a single Zn-air battery and proton exchange membrane fuel cell respectively.Furthermore,theoretical calculations confirm that the unique LaN_(4)O moiety adjacent to the microspore vacancy with graphitic N dopant not only presents a negative shift of the La 5d orbitals,significantly lowering the adsorption energy of*OOH in ORR,but also induces the carbon atom near the graphitic N as one more active site for ORR.This work highlights the potential application of La-N-C as an efficient ORR catalyst in green energy conversion devices.
文摘In this paper,we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon(ZnNC)via a green aqueous impregnation method followed by a two-step annealing protocol(H_(2)/Ar,600 and 800℃)to circumvent the sintering issues imposed by conventional thermodynamics.Physical characterizations(X-ray diffraction,high-angle annular dark-field scanning transmission electron microscopy,X-ray absorption spectroscopy)and theoretical calculations reveal that low-temperature annealing at 600℃stabilizes sub-nano disordered PtFe alloys via the strong metal-support interactions(SMSI)between Zn in ZnNC and Pt precursors,while high-temperature treatment at 800℃promotes Zn diffusion from the support into the alloy bulk and simultaneously triggers the disorder-to-order phase transition.The as-prepared ZnNC-15PtFeZn exhibits an initial mass activity of 0.769 mA/μgPt and retains 61.7%of its activity after 30000 cycles of accelerated stress testing(AST).Notably,when used as a cathode catalyst in MEA,ZnNC-15PtFeZn achieves superior power density(2.018 W/cm^(2)under H_(2)-O_(2))at half the Pt loading(0.05 mg/cm^(2))of state-of-the-art commercial Pt/C,highlighting its potential for low-Pt PEMFCs.Density functional theory confirms that Fe enhances ORR activity via ligand effects,while Zn strengthens Pt-Fe/Zn bonding(elevating vacancy formation energies),thereby improving structural stability.This mild,scalable aqueous impregnation strategy offers a general approach for synthesizing multi-component ordered alloys in electrocatalysis.
基金supported the National Natural Science Foundation of China(Nos.22108306 and 22478432)Taishan Scholars Program of Shandong Province(No.tsqn201909065)the Natural Science Foundation of Shandong Province(Nos.ZR2024JQ004 and ZR2021YQ15).
文摘Proton exchange membrane fuel cells have been identified as a potentially valuable technology for the efficient conversion of hydrogen energy into electrical energy.Nevertheless,one significant constraint on the performance of fuel cells is the oxygen reduction reaction(ORR).It is meaningful to progress the development of representative ORR electrocatalysts.In recent times,there has been an intensified focus on single-atom catalysts(SACs)due to the advantages of homogeneous distribution and high atom utilization efficiency.In particular,the coordination structure of metal sites plays an important role in the electrochemical performance of SACs.However,the relationship between coordination structures and catalytic performance remains unclear.In this review,we summarized the research progress on SACs in electrocatalytic ORR in recent years.Then the structure-activity relationship in the symmetric and asymmetric coordination structures of SACs was clarified.We further proposed rational design principles for regulating the coordination structure of SACs.Finally,the opportunities and challenges were discussed.
基金financially supported by the National Natural Science Foundation of China(No.22278042)the National Natural Science Foundation of Jiangsu Province(No.BK20240567)+2 种基金the Introduction and Cultivation of Leading Innovative Talents Foundation of Changzhou,Jiangsu Province(No.CQ20220093)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.24KJD530001)the Open Project Program of Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science(No.M2024-7),MOE
文摘Regulating the electronic structure and oxygencontaining intermediates adsorption behavior on Fe-based catalysts is of great significance to cope with the sluggish oxygen reduction reaction(ORR)kinetics,but it still remains a great challenge.In this work,Fe atom clusters(Fe_(AC))modified by high-density Cu single atoms(Cu_(SA))in a N,S-doped porous carbon substrate(Fe_(AC)/Cu_(SA)@NCS)is reported for enhanced ORR electrocatalysis.Fe_(AC)/Cu_(SA)@NCS exhibits excellent ORR performance with a half-wave potential(E_(1/2))of 0.911 V,a high four-electron process selectivity and excellent stability.The ORR performance is also verified in the Fe_(AC)/Cu_(SA)@NCS-based Zn-air battery,which shows a high peak power density of 192.67 mW cm^(-2),a higher specific capacity of 808.3 mAh g^(-1)and impressive charge-discharge cycle stability.Moreover,density functional theory calculations show that Cu single atoms synergistically modulate the electronic structure Fe active atoms in Fe atomic clusters,reducing the energy barrier of the rate-determining step(i.e.,*OH desorption)on Fe_(AC)/Cu_(SA)@NCS.This work provides an effective way to regulate the electronic structure of Fe-based catalysts and optimize their electrocatalytic activity based on the introduction of a second metal source.
基金supported by the National Natural Science Foundation of China(No.12205165).
文摘Efficient electrocatalysts for oxygen reduction reaction(ORR)show significant importance for advancing the performance and affordability of proton exchange membrane fuel cells and other energy conversion devices.Herein,PtCo_(3)nanoalloys dispersed on a carbon black support,were prepared using ultrafast Joule heating method.By tuning the heating modes,such as high-temperature shock and heating for 2 s,two kinds of PtCo_(3)nanoalloys with varying crystallinities were obtained,referred to as PtCo_(3)-HTS(average size of 5.4 nm)and PtCo_(3)-HT-2 s(average size of 6.4 nm),respectively.Impressively,PtCo_(3)-HTS exhibited superior electrocatalytic ORR activity and stability(E_(1/2)=0.897 V vs.RHE and 36mV negative shift after 50,000 cycles),outperforming PtCo_(3)-HT-2 s(E_(1/2)=0.872 V and 16.2mV negative shift),as well as the commercial Pt/C(20 wt%)catalyst(E_(1/2)=0.847 V and 21.0mV negative shift).The enhanced ORR performance of PtCo_(3)-HTS may be attributed to its low crystallinity,which results in an active local electronic structure and chemical state,as confirmed by X-ray diffraction(XRD)and X-ray absorption fine structure(XAFS)analyses.The ultrafast Joule heating method showed great potential for crystallinity engineering,offering a promising pathway to revolutionize the manufacturing of cost-effective and environmentally friendly catalysts for clean energy applications.
基金supported by the National Natural Science Foundation of China(22262010,22062005,22165005,U20A20128)Guangxi Science and Technology Fund for Distinguished HighTalent Introduction Program(AC22035091)Guangxi Science Fund for Distinguished Young Scholars(2019GXNSFFA245016)。
文摘Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.
基金supported by the National Natural Science Foundation of China(22379111 and 22179093)。
文摘Hydrogen peroxide(H_(2)O_(2))electrosynthesis via two-electron oxygen reduction reaction(2e-ORR)is a promising alternative for the energy-intensive anthraquinone process.However,the instability of the catalytic metal sites in the state-of-the-art metal single-atom catalysts(M-SACs)hinders their further industrial applications,and the high potential and valueless oxygen product of the conventional anodic oxygen evolution reaction(OER)further limit the economic efficiency of this technology.To address this,a dynamically local structure reconstruction strategy is proposed to in situ transfer the active sites from unstable metal sites to the stable surrounding carbon sites for efficient and durable 2e^(-)ORR electrocatalysis.For the as-designed Mn-N_(3)O-C catalyst,by reconstructing Mn sites into Mn(^(*)OH),the Mn sites were passivated and carbon sites adjacent to the O atom were verified to be the actual active sites by in situ characterization and theoretical calculation.Consequently,Mn-N_(3)O-C exhibited>80%Faradaic efficiency and superior long-term durability over 100 h for H_(2)O_(2)electrosynthesis at~120 mA cm^(-2).In addition,coupling anodic ethylene glycol oxidation reaction(EGOR)further improves the efficiency and economic viability of the H_(2)O_(2)electrosynthesis system.This two-pronged strategy thus opens up a new opportunity for the development of stable H_(2)O_(2)electrosynthesis with low energy consumption and superior economic performance.
