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
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
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 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
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
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
In the pursuit of high-performance proton exchange membrane fuel cells(PEMFCs),obtaining durable Pt-based intermetallic catalysts with small particle sizes for oxygen reduction reaction(ORR)stands as a crucial yet cha...In the pursuit of high-performance proton exchange membrane fuel cells(PEMFCs),obtaining durable Pt-based intermetallic catalysts with small particle sizes for oxygen reduction reaction(ORR)stands as a crucial yet challenging topic.Herein,we propose an idea of catalyst design utilizing Fe-phenanthroline(Phen)complex as precursor to integrate metal-nitrogen-carbon(M-N-C)with the strong anchoring effect into carbon shells,synthesizing highly ordered and small-sized(3.59 nm)PtFe intermetallic catalyst coated with iron-nitrogen-carbon(FeNC)shells(L1_(0)-PtFe@FeNC).The strong Fe-Phen interaction ensures the uniform dispersion of Fe species on Pt seeds so as to form protective shells suppressing the agglomeration and dissolution of PtFe nanoparticles(NPs)under the high-temperature annealing or harsh operational conditions.It exhibits excellent mass activity(MA)that is about five-fold increase compared to the commercial Pt/C,as well as the significantly improved MA retention after 30,000 potential cycles(68.2%vs.45.3%).Nitrogen-doped carbon(NC)shells and pure carbon(C)shells are used as comparison to demonstrate the advantages of FeNC shells.Durability test results show that NC and C shells obviously degrade after potential cycles,while well-preserved FeNC shells guarantee catalyst stability.Theoretical calculations reveal that the strong binding between FeNC shells and the Pt surface enhances the stability of both the nanoparticles and the FeNC shells.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
The development of high-performance and cost-efficient catalysts holds great significance in facilitating oxygen reduction reaction(ORR),which is a pivotal process in next-generation energy storage devices,such as alu...The development of high-performance and cost-efficient catalysts holds great significance in facilitating oxygen reduction reaction(ORR),which is a pivotal process in next-generation energy storage devices,such as aluminum-air batteries.Transition metal sulfides have been proposed as promising non-noble metal ORR catalysts.However,achieving platinum(Pt)-comparable activity remains a challenge.Herein,a Co-doping-triggered electronic reconfiguration strategy is reported to tune the charge distribution and coordination state of ZnS nanoparticles anchored on N,S co-doped carbon(ZnS/NSC),thereby optimizing the intermediate adsorption kinetics and promoting ORR activity.The half-wave potential of 0.87 V as well as 100-h continuous durability are obtained by Co-doped ZnS/NSC in alkaline media.In addition,the solid-state aluminum-air battery is further assembled by using Co-doped ZnS/NSC as a cathode catalyst,achieving a maximum peak density of 100 mW·cm^(−2) and discharge duration over 55 h.Density functional theory(DFT)calculations reveal that high electronegative Co-doping is beneficial for the construct of charge-transfer avenue and optimization of intermediate adsorption procedure.This study presents an efficient approach for preparing metal sulfides with high catalytic activity toward ORR in flexible metal-air batteries.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
Disrupting the symmetric electron distribution of porphyrin-like Fe singleatom catalysts has been considered as an effective way to harvest high intrinsic activity.Understanding the catalytic performance governed by g...Disrupting the symmetric electron distribution of porphyrin-like Fe singleatom catalysts has been considered as an effective way to harvest high intrinsic activity.Understanding the catalytic performance governed by geometric microstrains is highly desirable for further optimization of such efficient sites.Here,we decipher the crucial role of local microstrain in boosting intrinsic activity and durability of asymmetric Fe single-atom catalysts(Fe-N_(3)S_(1))by replacing one N atom with S atom.The high-curvature hollow carbon nanosphere substrate introduces 1.3%local compressive strain to Fe-N bonds and 1.5%tensile strain to Fe-S bonds,downshifting the d-band center and accelerating the kinetics of*OH reduction.Consequently,highly curved Fe-N_(3)S_(1)sites anchored on hollow carbon nanosphere(FeNS-HNS-20)exhibit negligible current loss,a high half-wave potential of 0.922 V vs.RHE and turnover frequency of 6.2 e^(−1)s^(−1)site−1,which are 53 mV more positive and 1.7 times that of flat Fe-N-S counterpart,respectively.More importantly,multiple operando spectroscopies monitored the dynamic optimization of strained Fe-N_(3)S_(1)sites into Fe-N_(3)sites,further mitigating the overadsorption of*OH intermediates.This work not only sheds new light on local microstrain-induced catalytic enhancement,but also provides a plausible direction for optimizing efficient asymmetric sites via geometric configurations.展开更多
As a versatile and environmentally benign oxidant,hydrogen peroxide(H_(2)O_(2))is highly desired in sanitation,disinfection,environmental remediation,and the chemical industry.Compared with the conventional anthraquin...As a versatile and environmentally benign oxidant,hydrogen peroxide(H_(2)O_(2))is highly desired in sanitation,disinfection,environmental remediation,and the chemical industry.Compared with the conventional anthraquinone process,the electrosynthesis of H_(2)O_(2)through the two-electron oxygen reduction reaction(2e^(−)ORR)is an efficient,competitive,and promising avenue.Electrocatalysts and devices are two core factors in 2e^(−)ORR,but the design principles of catalysts for different pH conditions and the development trends of relevant synthesis devices remain unclear.To this end,this review adopts a multiscale perspective to summarize recent advancements in the design principles,catalytic mechanisms,and application prospects of 2e^(−)ORR catalysts,with a particular focus on the influence of pH conditions,aiming at providing guidance for the selective design of advanced 2e^(−)ORR catalysts for highly-efficient H_(2)O_(2)production.Moreover,in response to diverse on-site application demands,we elaborate on the evolution of H_(2)O_(2)electrosynthesis devices,from rotating ring-disk electrodes and H-type cells to diverse flow-type cells.We elaborate on their characteristics and shortcomings,which can be beneficial for their further upgrades and customized applications.These insights may inspire the rational design of innovative catalysts and devices with high performance and wide serviceability for large-scale implementations.展开更多
The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction(ORR)is essential for the commercialization of proton exchange membrane fuel cells(PEMFCs).Herein,we designed Pt...The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction(ORR)is essential for the commercialization of proton exchange membrane fuel cells(PEMFCs).Herein,we designed Pt@Pt_(3)Ti core-shell nanoparticles with atomic-controllable shells through precise thermal diffusing Ti into Pt nanoparticles for effective and durable ORR.Combining theoretical and experiment analysis,we found that the lattice strain of Pt_(3)Ti shells can be tailored by precisely controlling the thick-ness of Pt_(3)Ti shell in atomic-scale on account of the lattice constant difference between Pt and Pt_(3)Ti to optimize adsorption properties of Pt_(3)Ti for ORR intermediates,thus enhancing its performance.The Pt@Pt_(3)Ti catalyst with one-atomic Pt_(3)Ti shell(Pt@1L-Pt_(3)Ti/TiO_(2)-C)demonstrates excellent performance with mass activity of 592 mA mgpt-1 and durability nearly 19.5-fold that of commercial Pt/C with negligible decay(2%)after 30,000 potential cycles(0.6-1.0 V vs.RHE).Notably,at higher potential cycles(1.0 V-1.5 V vs.RHE),Pt@1L-Pt_(3)Ti/TiO_(2)-C also showed far superior durability than Pt/C(9.6%decayed while 54.8% for commercial Pt/C).This excellent stability is derived from the intrinsic stability of Pt_(3)Ti alloy and the confinement effect of TiO_(2)-C.The catalyst's enhancement was further confirmed in PEMFC configuration.展开更多
The development of efficient and durable electrocatalysts for oxygen reduction reaction(ORR)holds a pivotal significance in the successful commercialization of proton exchange membrane fuel cells(PEMFCs)but is still c...The development of efficient and durable electrocatalysts for oxygen reduction reaction(ORR)holds a pivotal significance in the successful commercialization of proton exchange membrane fuel cells(PEMFCs)but is still challenging.Herein,we report a worm-liked PtCu nanocrystals dispersed on nitrogen-doped carbon hollow microspheres(Pt_(0.38)Cu_(0.62)/N-HCS).Benefiting from its structural and compositional advantages,the resulting Pt_(0.38)Cu_(0.62)/N-HCS catalyst delivers exceptional electrocatalytic activity for ORR,with a half-wave potential(E_(1/2))of 0.837 V,a mass activity of 0.672 A mgPt^(-1),and a Tafel slope of 50.66 mV dec^(-1),surpassing that of commercial Pt/C.Moreover,the Pt_(0.38)Cu_(0.62)/N-HCS follows the desired four-electron transfer mechanism throughout the ORR process,thereby displaying a high selectivity for direct reduction of O_(2)to H_(2)O.Remarkably,this catalyst also showcases high stability,with only a 25 mV drop in E_(1/2)after 10,000 cycles in an acidic electrolyte.Theoretical calculations elucidate the incorporation of Cu into Pt lattice induces compressive strain,which effectively tailors the d band center of Pt active sites and strengthens the surface chemisorption of O_(2)molecules on PtCu alloys.Consequently,the Pt_(0.38)Cu_(0.62)/N-HCS catalyst exhibits an improved ability to adsorb O_(2)molecules on its surface,accelerating the reaction kinetics of O_(2)conversion to*OOH.Additionally,Cu atoms,not only serving as sacrificial anode,undergo preferential oxidation during PEMFCs operation when compared to Pt,but also the stable Cu species in PtCu alloys contributes significantly to maintaining the strain effect,collectively enhancing both activity and durability.Overall,this research offers an effective and promising approach to enhance the activity and stability of Pt-based ORR electrocatalysts in PEMFCs.展开更多
As a catalyst of the air cathode in zinc-air batteries,tungstic acid ferrous(FeWO_(4)),a nanoscale transition metal tungstate,shows a broad application prospect in the oxygen reduction reaction(ORR).While FeWO_(4)poss...As a catalyst of the air cathode in zinc-air batteries,tungstic acid ferrous(FeWO_(4)),a nanoscale transition metal tungstate,shows a broad application prospect in the oxygen reduction reaction(ORR).While FeWO_(4)possesses favorable electrochemical properties and thermodynamic stability,its intrinsic semiconductor characteristics result in a relatively slow electron transfer rate,limiting the ORR catalytic activity.In this work,the electronic structure of FeWO_(4)is significantly modulated by introducing phosphorus(P)atoms with abundant valence electrons.The P doping can adjust the electronic structure of FeWO_(4)and then optimize oxygen-containing intermediates'absorption/desorption efficiency to achieve improved ORR activity.Furthermore,the sodium chloride template is utilized to construct a porous carbon framework for anchoring phosphorus-doped iron tungstate(P-FeWO_(4)/PNC).The porous carbon skeleton provides numerous active sites for the absorption/desorption and redox reactions on the P-FeWO_(4)/PNC surface and serves as mass transport channels for reactants and intermediates.The P-FeWO_(4)/PNC demonstrates ORR performance(E1/2=0.86 V vs.RHE).Furthermore,the zinc-air batteries incorporating the P-FeWO_(4)/PNC composite demonstrate an increased peak power density(172.2 mW·cm^(-2)),high specific capacity(810.1 mAh·g^(-1)),and sustained long-term cycling stability lasting up to 240 h.This research not only contributes to the advancement of cost-effective tungsten-based non-precious metallic ORR catalysts,but also guides their utilization in zinc-air batteries.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
The advancement of efficient,cheap,and durable catalysts for oxygen reduction reaction(ORR)to substitute Pt/C in metal-air batteries is of paramount importance.However,traditional solvent-based methods fall short in t...The advancement of efficient,cheap,and durable catalysts for oxygen reduction reaction(ORR)to substitute Pt/C in metal-air batteries is of paramount importance.However,traditional solvent-based methods fall short in terms of environmental benign and scalability.Herein,a solvent-free organic-inorganic selfassembly approach is explored to construct cobalt single atom and cobalt nanocluster decorated nitrogendoped porous carbon spheres(Co-SA/NC@NCS).The solvent-free synthesis demonstrates an impressively high yield(282 g/L)and the resultant Co-SA/NC@NCS possesses a high N content(6.9 wt%).Density functional theory calculations disclose that the Co-SAs and Co-NCs are able to optimize the surface oxygen adsorption capability and enhance the conductivity of the NCS,thereby facilitating the ORR performance.The sol vent-free synthesis is also feasible for the synthesis of other non-noble metal element(Fe,Ni,and Zn)decorated nitrogen-doped porous carbon spheres.展开更多
In this research,we present a comprehensive investigation on the catalyst screening,reaction mechanism,and electrocatalytic properties of two-dimensional monoatomic metalloporphyrinoid(MPor)materials for the oxygen re...In this research,we present a comprehensive investigation on the catalyst screening,reaction mechanism,and electrocatalytic properties of two-dimensional monoatomic metalloporphyrinoid(MPor)materials for the oxygen reduction reaction(ORR).Through a combination of high-throughput screening,first-principles DFT calculations,and molecular dynamics simulations,we uncovered some promising oxygen reduction catalysts with limiting potentials of 0.60,0.57,0.56 V under acidic medium,and-0.17,-0.20,-0.21 V under basic medium for M=Co,Fe,Mn,respectively.Full reaction pathway search demonstrates that Co Por is a special case with 2e^(–)and 4e^(–)paths under both acidic and basic media,and for Fe Por and Mn Por,only 4e^(–)path is viable.In-depth analyses indicate that the adsorption free energy of OH and limiting potential shows the volcano curve relationship,which can guide the design and optimization of the ORR catalysts.The crystal orbital Hamiltonian population(COHP)between M and O in O_(2)-MPor can well explain why only Co Por has a 2e^(–)path,while other metals do not,because the Co–O bond is much weaker compared to other M–O bonds.Our research will shed some insights on designing efficient ORR catalysts,and stimulate the experimental efforts in this direction.展开更多
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In the pursuit of high-performance proton exchange membrane fuel cells(PEMFCs),obtaining durable Pt-based intermetallic catalysts with small particle sizes for oxygen reduction reaction(ORR)stands as a crucial yet challenging topic.Herein,we propose an idea of catalyst design utilizing Fe-phenanthroline(Phen)complex as precursor to integrate metal-nitrogen-carbon(M-N-C)with the strong anchoring effect into carbon shells,synthesizing highly ordered and small-sized(3.59 nm)PtFe intermetallic catalyst coated with iron-nitrogen-carbon(FeNC)shells(L1_(0)-PtFe@FeNC).The strong Fe-Phen interaction ensures the uniform dispersion of Fe species on Pt seeds so as to form protective shells suppressing the agglomeration and dissolution of PtFe nanoparticles(NPs)under the high-temperature annealing or harsh operational conditions.It exhibits excellent mass activity(MA)that is about five-fold increase compared to the commercial Pt/C,as well as the significantly improved MA retention after 30,000 potential cycles(68.2%vs.45.3%).Nitrogen-doped carbon(NC)shells and pure carbon(C)shells are used as comparison to demonstrate the advantages of FeNC shells.Durability test results show that NC and C shells obviously degrade after potential cycles,while well-preserved FeNC shells guarantee catalyst stability.Theoretical calculations reveal that the strong binding between FeNC shells and the Pt surface enhances the stability of both the nanoparticles and the FeNC shells.
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financially sponsored by the National Natural Science Foundation of China(Nos.52302039 and 52301043)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110676)+2 种基金Shenzhen Science and Technology Program(Nos.JCYJ20220531095404009,RCBS20221008093057027 and GXWD20231129113217001)the Postdoctoral Research Startup Expenses of Shenzhen(No.NA25501001)Shenzhen Introduce High-level Talents and Scientific Research Startup Founds(No.NA11409005).
文摘The development of high-performance and cost-efficient catalysts holds great significance in facilitating oxygen reduction reaction(ORR),which is a pivotal process in next-generation energy storage devices,such as aluminum-air batteries.Transition metal sulfides have been proposed as promising non-noble metal ORR catalysts.However,achieving platinum(Pt)-comparable activity remains a challenge.Herein,a Co-doping-triggered electronic reconfiguration strategy is reported to tune the charge distribution and coordination state of ZnS nanoparticles anchored on N,S co-doped carbon(ZnS/NSC),thereby optimizing the intermediate adsorption kinetics and promoting ORR activity.The half-wave potential of 0.87 V as well as 100-h continuous durability are obtained by Co-doped ZnS/NSC in alkaline media.In addition,the solid-state aluminum-air battery is further assembled by using Co-doped ZnS/NSC as a cathode catalyst,achieving a maximum peak density of 100 mW·cm^(−2) and discharge duration over 55 h.Density functional theory(DFT)calculations reveal that high electronegative Co-doping is beneficial for the construct of charge-transfer avenue and optimization of intermediate adsorption procedure.This study presents an efficient approach for preparing metal sulfides with high catalytic activity toward ORR in flexible metal-air batteries.
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.
基金supported by the Natural Science Foundation of Shandong Province (ZR2024JQ004)the National Natural Science Foundation of China (22108306, 22478432)Taishan Scholars Program of Shandong Province
文摘Disrupting the symmetric electron distribution of porphyrin-like Fe singleatom catalysts has been considered as an effective way to harvest high intrinsic activity.Understanding the catalytic performance governed by geometric microstrains is highly desirable for further optimization of such efficient sites.Here,we decipher the crucial role of local microstrain in boosting intrinsic activity and durability of asymmetric Fe single-atom catalysts(Fe-N_(3)S_(1))by replacing one N atom with S atom.The high-curvature hollow carbon nanosphere substrate introduces 1.3%local compressive strain to Fe-N bonds and 1.5%tensile strain to Fe-S bonds,downshifting the d-band center and accelerating the kinetics of*OH reduction.Consequently,highly curved Fe-N_(3)S_(1)sites anchored on hollow carbon nanosphere(FeNS-HNS-20)exhibit negligible current loss,a high half-wave potential of 0.922 V vs.RHE and turnover frequency of 6.2 e^(−1)s^(−1)site−1,which are 53 mV more positive and 1.7 times that of flat Fe-N-S counterpart,respectively.More importantly,multiple operando spectroscopies monitored the dynamic optimization of strained Fe-N_(3)S_(1)sites into Fe-N_(3)sites,further mitigating the overadsorption of*OH intermediates.This work not only sheds new light on local microstrain-induced catalytic enhancement,but also provides a plausible direction for optimizing efficient asymmetric sites via geometric configurations.
基金supported by the National Natural Science Foundation of China(Nos.22102073,22075147).
文摘As a versatile and environmentally benign oxidant,hydrogen peroxide(H_(2)O_(2))is highly desired in sanitation,disinfection,environmental remediation,and the chemical industry.Compared with the conventional anthraquinone process,the electrosynthesis of H_(2)O_(2)through the two-electron oxygen reduction reaction(2e^(−)ORR)is an efficient,competitive,and promising avenue.Electrocatalysts and devices are two core factors in 2e^(−)ORR,but the design principles of catalysts for different pH conditions and the development trends of relevant synthesis devices remain unclear.To this end,this review adopts a multiscale perspective to summarize recent advancements in the design principles,catalytic mechanisms,and application prospects of 2e^(−)ORR catalysts,with a particular focus on the influence of pH conditions,aiming at providing guidance for the selective design of advanced 2e^(−)ORR catalysts for highly-efficient H_(2)O_(2)production.Moreover,in response to diverse on-site application demands,we elaborate on the evolution of H_(2)O_(2)electrosynthesis devices,from rotating ring-disk electrodes and H-type cells to diverse flow-type cells.We elaborate on their characteristics and shortcomings,which can be beneficial for their further upgrades and customized applications.These insights may inspire the rational design of innovative catalysts and devices with high performance and wide serviceability for large-scale implementations.
基金supported by the National Natural Science Foundation of China(No.21875039)the Project on the Integration of Industry-Education-Research of Fujian Province(No.2021H6020)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology).
文摘The exploitation of durable and highly active Pt-based electrocatalysts for the oxygen reduction reaction(ORR)is essential for the commercialization of proton exchange membrane fuel cells(PEMFCs).Herein,we designed Pt@Pt_(3)Ti core-shell nanoparticles with atomic-controllable shells through precise thermal diffusing Ti into Pt nanoparticles for effective and durable ORR.Combining theoretical and experiment analysis,we found that the lattice strain of Pt_(3)Ti shells can be tailored by precisely controlling the thick-ness of Pt_(3)Ti shell in atomic-scale on account of the lattice constant difference between Pt and Pt_(3)Ti to optimize adsorption properties of Pt_(3)Ti for ORR intermediates,thus enhancing its performance.The Pt@Pt_(3)Ti catalyst with one-atomic Pt_(3)Ti shell(Pt@1L-Pt_(3)Ti/TiO_(2)-C)demonstrates excellent performance with mass activity of 592 mA mgpt-1 and durability nearly 19.5-fold that of commercial Pt/C with negligible decay(2%)after 30,000 potential cycles(0.6-1.0 V vs.RHE).Notably,at higher potential cycles(1.0 V-1.5 V vs.RHE),Pt@1L-Pt_(3)Ti/TiO_(2)-C also showed far superior durability than Pt/C(9.6%decayed while 54.8% for commercial Pt/C).This excellent stability is derived from the intrinsic stability of Pt_(3)Ti alloy and the confinement effect of TiO_(2)-C.The catalyst's enhancement was further confirmed in PEMFC configuration.
基金the Young Elite Scientists Sponsorship Program by CAST(2021QNRC001)Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0557,cstb2023nscq-msx0979)+3 种基金Talent Introduction of Chongqing University of Science and Technology(ckrc2021050,ckrc20230401,ckrc2021053)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202201532,KJQN202301542)the National Natural Science Foundation of China(22109016)Open Research Fund of CNMGE Platform&NSCC-TJ(CNMGE2023016).
文摘The development of efficient and durable electrocatalysts for oxygen reduction reaction(ORR)holds a pivotal significance in the successful commercialization of proton exchange membrane fuel cells(PEMFCs)but is still challenging.Herein,we report a worm-liked PtCu nanocrystals dispersed on nitrogen-doped carbon hollow microspheres(Pt_(0.38)Cu_(0.62)/N-HCS).Benefiting from its structural and compositional advantages,the resulting Pt_(0.38)Cu_(0.62)/N-HCS catalyst delivers exceptional electrocatalytic activity for ORR,with a half-wave potential(E_(1/2))of 0.837 V,a mass activity of 0.672 A mgPt^(-1),and a Tafel slope of 50.66 mV dec^(-1),surpassing that of commercial Pt/C.Moreover,the Pt_(0.38)Cu_(0.62)/N-HCS follows the desired four-electron transfer mechanism throughout the ORR process,thereby displaying a high selectivity for direct reduction of O_(2)to H_(2)O.Remarkably,this catalyst also showcases high stability,with only a 25 mV drop in E_(1/2)after 10,000 cycles in an acidic electrolyte.Theoretical calculations elucidate the incorporation of Cu into Pt lattice induces compressive strain,which effectively tailors the d band center of Pt active sites and strengthens the surface chemisorption of O_(2)molecules on PtCu alloys.Consequently,the Pt_(0.38)Cu_(0.62)/N-HCS catalyst exhibits an improved ability to adsorb O_(2)molecules on its surface,accelerating the reaction kinetics of O_(2)conversion to*OOH.Additionally,Cu atoms,not only serving as sacrificial anode,undergo preferential oxidation during PEMFCs operation when compared to Pt,but also the stable Cu species in PtCu alloys contributes significantly to maintaining the strain effect,collectively enhancing both activity and durability.Overall,this research offers an effective and promising approach to enhance the activity and stability of Pt-based ORR electrocatalysts in PEMFCs.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22178148 and 22278193)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘As a catalyst of the air cathode in zinc-air batteries,tungstic acid ferrous(FeWO_(4)),a nanoscale transition metal tungstate,shows a broad application prospect in the oxygen reduction reaction(ORR).While FeWO_(4)possesses favorable electrochemical properties and thermodynamic stability,its intrinsic semiconductor characteristics result in a relatively slow electron transfer rate,limiting the ORR catalytic activity.In this work,the electronic structure of FeWO_(4)is significantly modulated by introducing phosphorus(P)atoms with abundant valence electrons.The P doping can adjust the electronic structure of FeWO_(4)and then optimize oxygen-containing intermediates'absorption/desorption efficiency to achieve improved ORR activity.Furthermore,the sodium chloride template is utilized to construct a porous carbon framework for anchoring phosphorus-doped iron tungstate(P-FeWO_(4)/PNC).The porous carbon skeleton provides numerous active sites for the absorption/desorption and redox reactions on the P-FeWO_(4)/PNC surface and serves as mass transport channels for reactants and intermediates.The P-FeWO_(4)/PNC demonstrates ORR performance(E1/2=0.86 V vs.RHE).Furthermore,the zinc-air batteries incorporating the P-FeWO_(4)/PNC composite demonstrate an increased peak power density(172.2 mW·cm^(-2)),high specific capacity(810.1 mAh·g^(-1)),and sustained long-term cycling stability lasting up to 240 h.This research not only contributes to the advancement of cost-effective tungsten-based non-precious metallic ORR catalysts,but also guides their utilization in zinc-air batteries.
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.
基金supported by the National Natural Science Foundation of China(No.52072283)the program of China Scholarship Council(No.202306950008)。
文摘The advancement of efficient,cheap,and durable catalysts for oxygen reduction reaction(ORR)to substitute Pt/C in metal-air batteries is of paramount importance.However,traditional solvent-based methods fall short in terms of environmental benign and scalability.Herein,a solvent-free organic-inorganic selfassembly approach is explored to construct cobalt single atom and cobalt nanocluster decorated nitrogendoped porous carbon spheres(Co-SA/NC@NCS).The solvent-free synthesis demonstrates an impressively high yield(282 g/L)and the resultant Co-SA/NC@NCS possesses a high N content(6.9 wt%).Density functional theory calculations disclose that the Co-SAs and Co-NCs are able to optimize the surface oxygen adsorption capability and enhance the conductivity of the NCS,thereby facilitating the ORR performance.The sol vent-free synthesis is also feasible for the synthesis of other non-noble metal element(Fe,Ni,and Zn)decorated nitrogen-doped porous carbon spheres.
基金financially supported by the National Key Research and Development Program of China(No.2021YFA1600800)the National Natural Science Foundation of China(Nos.22073033,21873032,21673087,and 21903032)+3 种基金the startup fund(Nos.2006013118 and 3004013105)from Huazhong University of Science and Technologythe Fundamental Research Funds for the Central Universities(No.2019kfy RCPY116)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003)support from the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515010382)。
文摘In this research,we present a comprehensive investigation on the catalyst screening,reaction mechanism,and electrocatalytic properties of two-dimensional monoatomic metalloporphyrinoid(MPor)materials for the oxygen reduction reaction(ORR).Through a combination of high-throughput screening,first-principles DFT calculations,and molecular dynamics simulations,we uncovered some promising oxygen reduction catalysts with limiting potentials of 0.60,0.57,0.56 V under acidic medium,and-0.17,-0.20,-0.21 V under basic medium for M=Co,Fe,Mn,respectively.Full reaction pathway search demonstrates that Co Por is a special case with 2e^(–)and 4e^(–)paths under both acidic and basic media,and for Fe Por and Mn Por,only 4e^(–)path is viable.In-depth analyses indicate that the adsorption free energy of OH and limiting potential shows the volcano curve relationship,which can guide the design and optimization of the ORR catalysts.The crystal orbital Hamiltonian population(COHP)between M and O in O_(2)-MPor can well explain why only Co Por has a 2e^(–)path,while other metals do not,because the Co–O bond is much weaker compared to other M–O bonds.Our research will shed some insights on designing efficient ORR catalysts,and stimulate the experimental efforts in this direction.
