摘要：The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ***,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in *** tests confirm that the introduction of Cu NPs improves the ORR performance *** obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V *** hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/***,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)*** work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.

摘要：The quest for low‐cost yet efficient non‐Pt electrocatalysts for the oxygen reduction reaction(ORR)has become one of the main focuses of research in the field of catalysis,which has implications for the development of the next generation of greener fuel ***,we comprehensively describe the'big picture'of recent advances made in the rational design of ORR electrocatalysts,including molecule‐based,metal‐oxide‐based,metal‐nanomaterial‐based and two‐dimensional *** metals can fabricate molecular electrocatalysts with N4‐macrocycles such as porphyrin‐class compounds and the so‐formed M-N-C active centre plays a crucial role in determining the catalytic performances towards the ***‐IV and‐V Transition metal oxides represent another class of promising alternative of Pt‐based catalysts for the ORR which catalytic activity largely depends on the surface structure and the introduction of surface *** advances in synthesis of metallic nanoparticles(NPs)allow for precise control over particle sizes and shapes and the crystalline facets exposed to enhance the ORR performance of ***‐dimensional materials such as functionalized grapheme or MoS2are emerging as novel electrocatalysts for the *** review covers various aspects towards the design of future ORR electrocatalysts,including the catalytic performance,stability,durability and *** novel electrocatalysts even surpass commercial Pt/C systems,demonstrating their potential to be alternatives in industrial *** the encouraging progress,challenges,which are also described,remain to be overcome before the real‐world application of novel ORR electrocatalysts.

摘要：Proton exchange membrane fuel cells(PEMFCs)are considered ideal energy‐conversion devices because of their environmentally friendly nature and high theoretical energy ***,cathodic polarization,which is a result of the sluggish oxygen reduction reaction(ORR)kinetics,is a significant source of energy loss and reduces fuel cell ***,the need to use Pt in commercial Pt/C cathodes has restricted their large‐scale application in fuel cells because of its high cost and poor ***,improvements in the activity and durability of Pt‐based catalyst are required to reduce the amount of Pt required and,thus,costs,while increasing the ORR rate and fuel cell power density and promoting widespread PEMFC *** recent years,atomically ordered Pt‐based intermetallic nanocrystals have received tremendous attention owing to their excellent activity and stability for the ***,in this review,we first introduce the formation of intermetallic compounds from the perspective of thermodynamics and kinetics to lay a theoretical foundation for the design of these *** addition,optimization strategies for Pt‐based ordered intermetallic catalysts are summarized in terms of the catalyst composition,size,and ***,we conclude with a discussion of the current challenges and future prospects of Pt‐based ordered *** review is designed to help readers gain insights into the recent developments in and rational design of Pt‐based intermetallic nanocrystals for the ORR and encourage research that will enable the commercialization of PEMFCs.

摘要：Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;however,it is still a challenge to achieve superior ORR performances,especially in acidic ***,by pyrolysis of mixed precursors of diammonium phosphate,melamine and hemin,we prepared a nanocomposite catalyst(denoted as FeP@PGL)composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles(NPs),which were encapsulated by in-situ formed phosphorus-doped graphene *** is found that phosphorous was preferentially doped in the coating layers on FeP NPs,instead of in the carbon *** FeP@PGL catalyst exhibited excellent ORR performance,with the onset and half-wave potential up to 1.01 and 0.90 V *** reversible hydrogen electrode(RHE)in alkaline media,and0.95 and 0.81 V *** in acidic media,*** thorough microscopy and spectroscopy characterizations,the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified,and the local work function of the catalyst surface was also reduced by the interfacial *** interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR *** study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst,but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.

摘要：A novel pure and N-doped waved-graphene electro-catalyst with various wavelengths for oxygen reduction reaction（ORR） is explored in acid medium based on the firstprinciples calculations. The associative and dissociative mechanism are both explored from the O_2 adsorption to the H_2 O formation step by step, from which the dissociative mechanism is likely the only way with an effective 4e-process. Furthermore, a very favorable and effective mechanism is proposed for the ORR process, which may provide a guideline on the design of new non-metal electro-catalysts.

摘要：Hydrogen peroxide(H2O2)is a very useful chemical reagent,but the current industrial methods for its production suffer from serious energy consumption *** high-activity and high-selectivity catalysts to electrocatalyze the oxygen reduction reaction(ORR)through a two-electron(2e^-)pathway is a very promising route to produce *** this work,we obtained partially oxidized multi-walled carbon nanotubes(MWCNTs)with controlled structure and composition by oxidation with concentrated sulfate and potassium permanganate at 40℃ for 1 h(O-CNTs-40-1).The outer layers of O-CNTs-40-1 are damaged with defects and oxygen-containing functional groups,while the inner layers are maintained *** optimized structure and composition of the partially oxidized MWCNTs ensure that O-CNTs-40-1 possesses both a sufficient number of catalytic sites and good *** results of rotating ring disk electrode measurements reveal that,among all oxidized MWCNTs,O-CNTs-40-1 shows the greatest improvement in hydrogen peroxide selectivity(from ~ 30% to ~ 50%)and electron transfer number(from ~ 3.4 to ~ 3.0)compared to those of the raw *** results of electrochemical impedance spectroscopy measurements indicate that both the charge-transfer and intrinsic resistances of O-CNTs-40-1 are lower than those of the raw MWCNTs and of the other oxidized ***,direct tests of the H2O2 production confirm the greatly improved catalytic activity of O-CNTs-40-1 relative to that of the raw MWCNTs.

摘要：Helical metal-organic frameworks(MOFs)were used as templates or precursors to fabricate helical carbon nanorods(HCNRs)for the first *** carbon contains many topological defects such as pentagonal or heptagonal carbons,which have the potential to facilitate oxygen reduction reactions(ORR).HCNRs show more positive onset/halfwave reduction potentials and higher limited current density than straight carbon nanorods(SCNRs).They also exhibit four-electron oxygen reduction in tests of ORR,while the alternative SCNRs prefer a two-electron reduction *** and theoretical studies reveal that these enhanced ORR activities can be attributed to pentagon/heptagon defects in *** work provides an effective strategy to synthesize helical,defect-rich carbon materials and opens up a new perspective for utilization of a spiral effect for the development of more effective electrocatalysts.

摘要：Developing high-efficient non-platinum （Pt） catalysts for oxygen reduction reaction （ORR） is the key to reduce the usage of Pt and the palladium （Pd）-based cata- lyst is a promising alternative. Here, we presented a facile approach to core/shell FePd/Pd nanoparticle （NP） catalyst with the FePd core in chemically ordered face-centered tetragonal （fct-） structure and the shell in controlled thickness from 0.32 to 0.81 nm via the thermal annealing of FePd NP followed by an electro-anodization process. With a 0.71 nm-thick Pd shell, the fct-FePd/Pd shows a robust catalytic activity and durability for ORR with the mass activities at 0.85 and 0.90 V reaching 453 and 96.7 A/mgpd, respectively, which are about 3.0 and 2.1 times higher than those of commercial Pt in alkaline media. This work presents a new class of non-Pt catalyst with superior performance to Pt for ORR catalysis, and the strategy demonstrated here can be extended to design highefficient catalysts for other chemical reactions.

摘要：Alloyed nanoparticles with core-shell structures provide a favorable model to modulate interfacial interaction and surface structures at the atomic level,which is important for designing electrocatalysts with high activity and ***,core-shell structured Pd3M@Pt/C nanoparticles with binary PdM alloy cores(M=Fe,Ni,and Co)and a monolayer Pt shell were successfully synthesized with diverse *** these,Pd3Fe@Pt/C exhibited the best oxygen reduction reaction catalytic performance,roughly 5.4 times more than that of the commercial Pt/C catalyst used as *** significantly enhanced activity is attributed to the combined effects of strain engineering,interfacial electron transfer,and improved Pt *** functional theory simulations and extended X-ray absorption fine structure analysis revealed that engineering the alloy core with moderate lattice mismatch and alloy composition(Pd3Fe)optimizes the surface oxygen adsorption energy,thereby rendering excellent electrocatalytic *** researches may use this study as a guide on the construction of highly effective core-shell electrocatalysts for various energy conversions and other applications.

摘要：Electronic regulation of carbon is essential for developing non-platinum electrocatalysts for oxygen reduction reactions(ORRs).In this work,we used Cs to further regulate the electronic structure of nitrogen-doped(N-doped)*** Cs atoms coordinated with the nitrogen atom in the N-doped carbon for injecting electrons into the carbon conjugate structure and reducing the work function of the carbon *** low-work-function surface improved electron donation,facilitated O_(2) dissociation,and enhanced the adsorption of an OOH^(*) ***,electrocatalytic performance for the ORR was *** material shows potential as an ORR electrocatalyst comparable with Pt/C.