High-entropy alloy(HEA)nanoparticles(NPs)have attracted great attention in electrocatalysis due to their tailorable complex compositions and unique properties.Herein,we introduce Fe,Co,Ni,Cr and Mn into the metal-poly...High-entropy alloy(HEA)nanoparticles(NPs)have attracted great attention in electrocatalysis due to their tailorable complex compositions and unique properties.Herein,we introduce Fe,Co,Ni,Cr and Mn into the metal-polyphenol coordination system to prepare HEA NPs enclosed in N-doped carbon(FeCoNiCrMn)with great potential for catalyzing oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).The unique high-entropy structural characteristics in FeCoNiCrMn facilitate effective interplay between metal species,leading to improved ORR(E_(1/2)=0.89 V)and OER(η=330 mV,j=10 mA·cm^(−2))activity.Additionally,FeCoNiCrMn exhibits excellent open-circuit voltage(1.523 V),power density(110 mW·cm^(−2))and long-term durability,outperforming Pt/C+IrO_(2) electrodes as a cathode catalyst in Zn-air batteries(ZABs).Such polyphenol-assisted alloying method broadens and simplifies the development of HEA electrocatalysts for high-performance ZABs.展开更多
Rational design of complex hollow nanostructures offers a great opportunity to construct various functional nanostructures.A novel in situ disassembly-polymerization-pyrolysis approach was developed to synthesize atom...Rational design of complex hollow nanostructures offers a great opportunity to construct various functional nanostructures.A novel in situ disassembly-polymerization-pyrolysis approach was developed to synthesize atomically dispersed Fe single atoms(Fe SAs)and tiny Co nanoparticles(Co NPs)binary sites embedded in double-shelled hollow carbon nanocages(Co NPs/Fe SAs DSCNs)without removing excess templates.The Co NPs/Fe SAs DSCNs displayed excellent bifunctional activity,boosting the realistic rechargeable zinc-air batteries with high efficiency,long-term durability,and reversibility,which is comparable to noble metal catalysts(Pt/C and RuO_(2)).The enhanced catalytic activity should be attributed to as well as the strong interactions between Fe SAs and Co NPs with the nitrogen-doped carbon matrix,the exposure of more active sites,and the high-flux mass transportation.In addition,the confinement effect between the double C–N shells prevented the aggregation and corrosion of metal atoms,thus improving the durability of the Co NPs/Fe SAs DSCNs,further highlighting the structural advantages of carbon nanoreactor.This work provides guidance for further rational design and preparation of complex hollow structure materials with advanced bifunctional air cathodes.展开更多
Oxygen electrocatalysts are of great importance for the air electrode in zinc-air batteries(ZABs).Owing to the high specific surface area,controllable pore size and unsaturated metal active sites,metal-organic framewo...Oxygen electrocatalysts are of great importance for the air electrode in zinc-air batteries(ZABs).Owing to the high specific surface area,controllable pore size and unsaturated metal active sites,metal-organic frameworks(MOFs)derivatives have been widely studied as oxygen electrocatalysts in ZABs.To date,many strategies have been developed to generate efficient oxygen electrocatalysts from MOFs for improving the performance of ZABs.In this review,the latest progress of the MOF-derived non-noble metal-oxygen electrocatalysts in ZABs is reviewed.The performance of these MOF-derived catalysts toward oxygen reduction,and oxygen evolution reactions is discussed based on the categories of metal-free carbon materials,single-atom catalysts,metal cluster/carbon composites and metal compound/carbon composites.Moreover,we provide a comprehensive overview on the design strategies of various MOF-derived non-noble metal-oxygen electrocatalysts and their structure-performance relationship.Finally,the challenges and perspectives are provided for further advancing the MOF-derived oxygen electrocatalysts in ZABs.展开更多
Rechargeable zinc-air batteries(ZABs)are currently receiving extensive attention because of their extremely high theoretical specific energy density,low manufacturing costs,and environmental friendliness.Exploring bif...Rechargeable zinc-air batteries(ZABs)are currently receiving extensive attention because of their extremely high theoretical specific energy density,low manufacturing costs,and environmental friendliness.Exploring bifunctional catalysts with high activity and stability to overcome sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction is critical for the development of rechargeable ZABs.Atomically dispersed metal-nitrogen-carbon(M-N-C)catalysts possessing prominent advantages of high metal atom utilization and electrocatalytic activity are promising candidates to promote oxygen electrocatalysis.In this work,general principles for designing atomically dispersed M-N-C are reviewed.Then,strategies aiming at enhancing the bifunctional catalytic activity and stability are presented.Finally,the challenges and perspectives of M-N-C bifunctional oxygen catalysts for ZABs are outlined.It is expected that this review will provide insights into the targeted optimization of atomically dispersed M-N-C catalysts in rechargeable ZABs.展开更多
Efficient bifunctional oxygen electrocatalysts for ORR and OER are fundamental to the development of high performance metal-air batteries.Herein,a facile cost-efficient two-step pyrolysis strategy for the fabrication ...Efficient bifunctional oxygen electrocatalysts for ORR and OER are fundamental to the development of high performance metal-air batteries.Herein,a facile cost-efficient two-step pyrolysis strategy for the fabrication of a bifunctional oxygen electrocatalyst has been proposed.The efficient non-preciousmetal-based electrocatalyst,Fe/Fe_(3)C@Fe-N_(x)-C consists of highly curved onion-like carbon shells that encapsulate Fe/Fe_(3)C nanoparticles,distributed on an extensively porous graphitic carbon aerogel.The obtained Fe/Fe_(3)C@Fe-N_(x)-C aerogel exhibited superb electrochemical activity,excellent durability,and high methanol tolerance.The experimental results indicated that the assembly of onion-like carbon shells with encapsulated Fe/Fe_(3)C yielded highly curved carbon surfaces with abundant Fe-Nxactive sites,a porous structure,and enhanced electrocatalytic activity towards ORR and OER,hence displaying promising potential for application as an air cathode in rechargeable Zn-air batteries.The constructed Zn-air battery possessed an exceptional peak power density of~147 mW cm^(-2),outstanding cycling stability(200 cycles,1 h per cycle),and a small voltage gap of 0.87 V.This study offers valuable insights regarding the construction of low-cost and highly active bifunctional oxygen electrocatalysts for efficient air batteries.展开更多
Designing rational transition-metal/carbon composites with highly dispersed and firmly anchored nanoparticles(NPs)to prevent agglomeration and shedding is crucial for realizing excellent electrocatalytic performances....Designing rational transition-metal/carbon composites with highly dispersed and firmly anchored nanoparticles(NPs)to prevent agglomeration and shedding is crucial for realizing excellent electrocatalytic performances.Herein,a biomass pore-confined strategy based on mesoporous willow catkin is explored to obtain uniformly dispersed CoFe NPs in N-doped carbon nanotubes and hollow carbon fibers(CoFe@N-CNTs/HCFs).The resultant catalyst exhibits enhanced electrocatalytic performance,which affords a half-wave potential of 0.86 V(vs.RHE)with a limited current density of 6.0 mA·cm^(-2)for oxygen reduction reaction and potential of 1.67 V(vs.RHE)at 10 mA·cm^(-2)in 0.1 M KOH for oxygen evolution reaction.When applied to rechargeable zinc-air batteries,a maximum power density of 340 mW·cm^(-2)and long-term cyclic durability over 800 h are achieved.Such superior bifunctional electrocatalytic activities are ascribed to the biocarbon matrix with abundant mesopores and unobstructed hollow channels,CoFe NPs with high dispersion and controllable nanoscale and the hybrid composite with optimized electronic structure.This work presents an effective approach for constraining the size and dispersion of NPs in a low-cost biocarbon substrate,offering valuable insights for designing advanced oxygen electrocatalysts.展开更多
Rational design and exploration of low-cost and robust bifunctional oxygen electrocatalysts are vitally important for developing high-performance zinc-air batteries(ZABs).Herein,we reported a facile yet cost-efficient...Rational design and exploration of low-cost and robust bifunctional oxygen electrocatalysts are vitally important for developing high-performance zinc-air batteries(ZABs).Herein,we reported a facile yet cost-efficient approach to construct a bifunctional oxygen reduction reaction(ORR)/oxygen evolution reaction(OER)electrocatalyst composed of N-doped porous carbon nanosheet flowers decorated with Fe Co nanoparticles(Fe Co/N-CF).Rational design of this catalyst is achieved by designing Schiff-base polymer with unique molecular structure via hydrogen bonding of cyanuramide and terephthalaldehyde polycondensate in the presence of metal cations.It exhibits excellent activity and stability for electrocatalysis of ORR/OER,enabling ZAB with a high peak power density of 172 m W cm^(-2)and a large specific capacity of 811 m A h g^(-1)Znat large current.The rechargeable ZAB demonstrates excellent durability for 1000 h with slight voltage decay,far outperforming a couple of precious Pt/Ir-based catalysts.Density functional theory(DFT)calculations reveal that high activity of bimetallic Fe Co stems from enhanced O_(2)and OH-adsorption and accelerated O_(2)dissociation by OAO bond activation.展开更多
An effective strategy of regulating active sites in bifunctional oxygen electrocatalysts is essentially desired,especially in rechargeable metal-air batteries(RZABs).Herein,a highly efficient electrocatalyst of CoFe a...An effective strategy of regulating active sites in bifunctional oxygen electrocatalysts is essentially desired,especially in rechargeable metal-air batteries(RZABs).Herein,a highly efficient electrocatalyst of CoFe alloys embedded in pyridinic nitrogen enriched N-doped carbon(CoFe/P-NC)is intelligently constructed by pyrolysis strategy.The high concentration of pyridinic nitrogen in CoFe/P-NC can significantly reprogram the redistribution of electron density of metal active sites,consequently optimizing the oxygen adsorption behavior.As expected,the pyridinic nitrogen guarantees CoFe/P-NC providing the low overpotential of the overall oxygen electrocatalytic process(ΔEORR-OER=0.73 V vs.RHE)and suppresses the benchmark electrocatalysts(Pt/C&RuO_(2)).Assembled rechargeable Zn-air battery using CoFe/P-NC demonstrates a promising peak power density of 172.0 mW cm^(-2),a high specific capacity of 805.0 mAh g^(-1)Zn and an excellent stability.This work proposes an interesting strategy for the design of robust oxygen electrocatalysts for energy conversion and storage fields.展开更多
With the rapid economic growth and the deepening awareness of sustainable development,the demand for green and efficient energy storage equipment increases.As a promising energy storage and conversion device,zinc-air ...With the rapid economic growth and the deepening awareness of sustainable development,the demand for green and efficient energy storage equipment increases.As a promising energy storage and conversion device,zinc-air batteries(ZABs)have the advantages of high theoretical specific energy density,low cost,and environmental friendliness.Nevertheless,the efficiency of ZABs is closely related to the electrocatalytic capacity of the air electrode due to its sluggish kinetics for oxygen reduction and evolution reaction(ORR/OER).Therefore,it is necessary to develop efficient catalysts to promote the reaction rate.Recently,cobalt-based materials have become a research hotspot for oxygen electrocatalysts owing to their rich natural content,high catalytic activity,and stability.In this review,the mechanisms of the OER/ORR reaction process,the catalyst's performance characterization,and the various combination methods with the current collector are systematically introduced and analyzed.Further,a broad overview of cobalt-based materials used as electrocatalysts for ZABs is presented,including cobalt-based perovskite,cobalt-nitrogen-carbon(Co-N-C)materials,cobalt oxides,cobalt-containing composite oxides,and cobalt sulfides/phosphides.Finally,various strategies for developing efficient electrocatalysts for ZABs are summarized,highlighting the challenges and future perspectives in designing novel catalysts.展开更多
Despite the extensive application of porous nanostructures as oxygen electrocatalysts, it is challenging to synthesize single-metal state materials with porous structures, especially the ultrasmall ones due to the uni...Despite the extensive application of porous nanostructures as oxygen electrocatalysts, it is challenging to synthesize single-metal state materials with porous structures, especially the ultrasmall ones due to the uniform diffusion of the same metal. Herein, we pioneer demonstrate a new size effect-based controllable synthesis strategy for the homogeneous Co nanokarstcaves assisted by Co-CN hybrids (CCHs). The preferential migration of cobalt atoms on the surface of small size zeolitic imidazolate framework (ZIF) with high surface energy during pyrolysis is the key factor for the formation of nanokarstcave structure. Furthermore, graphene can act as a diffusion barrier to prevent the agglomeration of nanoparticles in the synthesis process, which also plays an important role in the formation of porous nanostructures. In alkali media, CCHs achieve overpotential of 287 mV (@10 mA·cm^(−2)) for oxygen evolution reaction (OER) and a half wave potential of 0.86 V (vs. RHE) for oxygen reduction reaction (ORR).展开更多
A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural featur...A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C_3N_4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6,show the highest N content of ~6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of ~66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal–air batteries.展开更多
Seawater battery is an advanced energy storage system that enables conversion of chemical energy to electricity by consuming metals,dissolved oxygen and seawater in anode,cathode and electrolyte,respectively.However,t...Seawater battery is an advanced energy storage system that enables conversion of chemical energy to electricity by consuming metals,dissolved oxygen and seawater in anode,cathode and electrolyte,respectively.However,the oxygen reduction reaction(ORR)activity and stability of electrocatalysts can be easily deactivated due to the severe Cl~-permeation and corrosion in seawater electrolyte.Herein,we developed a structural buffer engineering strategy by spontaneously anchoring Cl~-intoα-Co(OH)_(2) as efficient and stable ORR electrocatalysts,in which the ultrathinα-Co(OH)_(2) nanosheets were synthesized using an ultrafast solution high-temperature shock(SHTS)strategy.The large lattice space(~0.8 nm)of layeredα-Co(OH)_(2) ensured the spontaneously penetration of Cl~-into the lattice structure and replaced part of OH~-to formα-Co(OH)_(2-x)Cl_x.The continuous leaching and compensating of saturated Cl inα-Co(OH)_(2-x)Cl_x could enhance the Cl~-corrosion resistance and modulate electronic structure of Co metallic sites,thus improving the ORR electrocatalytic activity and stability in seawater electrolyte.Theα-Co(OH)_(2-x)Cl_x seawater batteries display superior onset and half-wave potentials of 0.71 and 0.66 V,respectively,which are much better than the counterparts ofα-Co(OH)_(2) and ofβ-Co(OH)_(2) with no Cl~-penetrating and no buffer structure.Theα-Co(OH)_(2-x)Cl_x-based seawater batteries display stable open-circuit potential of 1.69 V and outstanding specific capacity of 1345 mAh·g^(-1).展开更多
To develop more ideal bifunctional heteroatom-doped carbon electrocatalysts toward the oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) for regenerative fuel cells and rechargeable metal–air batterie...To develop more ideal bifunctional heteroatom-doped carbon electrocatalysts toward the oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) for regenerative fuel cells and rechargeable metal–air batteries, herein, tobacco-derived N-containing ordered mesoporous carbon(N-OMC) electrocatalysts with different N species distributions are designed. Results indicate that the as-prepared N-OMC with more pyrrolic and pyridinic Ns exhibits much higher activities for the ORR and OER than N-OMC with more graphitic N in both acidic and alkaline media, suggesting that the increase of pyrrolic and pyridinic Ns favors the improvement of ORR and OER activities of the N-containing carbon catalysts, and showing a great potential for the designing of more effective, lower-cost ORR and OER bifunctional electrocatalysts for future regenerative fuel cells and rechargeable metal–air batteries.展开更多
Developing non-precious metal catalyst with high activity, good stability and low cost for electrocatalytic oxygen reduction reaction（ORR） is critical for the wide application of energy conversion system. Here, we d...Developing non-precious metal catalyst with high activity, good stability and low cost for electrocatalytic oxygen reduction reaction（ORR） is critical for the wide application of energy conversion system. Here, we developed a cost–effective synthetic strategy via silica assistance to obtain a novel FeC/Fe–N–C（named as COPBP-PB-Fe-900-SiO） catalyst with effective active sites of Fe–Nand FeC from the rational design two-dimensional covalent organic polymer（COPBP-PB）. The nitrogen-rich COP effectively promotes the formation of active Fe–Nsites. Additionally, the silica not only can effectively suppress the formation of large Fe-based particles in the catalysts, but also increases the degree of carbonization of the catalyst.The as-prepared COPBP-PB-Fe-900-SiOcatalyst exhibits high electrocatalytic activity for ORR with a halfwave potential of 0.85 V vs. reversible hydrogen electrode（RHE）, showing comparable activity as compared with the commercial Pt/C catalysts in alkaline media. Moreover, this catalyst also shows a high stability with a nearly constant onset potential and half-wave potential after 10,000 cycles. The present work is highly meaningful for developing ORR electrocatalysts toward wide applications.展开更多
The requirement for a sustainable and renewable energy has inspired substantial interests in designing and developing earth-abundant and high-effectiveness electrocatalysts/electrodes for fuel cells and metal-air batt...The requirement for a sustainable and renewable energy has inspired substantial interests in designing and developing earth-abundant and high-effectiveness electrocatalysts/electrodes for fuel cells and metal-air batteries,in which oxygen reduction reaction(ORR)plays a crucial role.Perovskite oxides have acquired rapid attention as ORR electrocatalysts to replace noble-metal-based catalysts owing to their intrinsic electrocatalytic activity,compositional and structural flexibility.Herein,we report a new Sc and P co-doped perovskite oxide(La0.8Sr0.2Mn0.95Sc0.025P0.025O3-δ,LSMSP)as an active and robust electrocatalyst for the ORR in an alkaline solution.LSMSP electrocatalyst shows superior ORR activity and stability than those of pristine La0.8Sr0.2MnO3-δ(LSM),Sc-doped LSM and P-doped LSM due to the optimized average valence of Mn ions,the large surface area,the smaller particle size and the synergetic effect introduced by the co-doping.Moreover,compared to the benchmark Pt/C electrocatalyst,LSMSP electrocatalyst displays comparable ORR activity and superior durability.These above results suggest that the co-doping strategy of Sc and P into perovskites is a useful method to design high-performance electrocatalysts for the ORR,which can be used in other electrocatalysis-based applications.展开更多
Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy usi...Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy using eutectic NaCl/ZnCl2 melt as airtight and swelling agent to obtain 3D mesoporous skeleton structured carbon from renewable lignin.The prepared lignin-derived biocarbon material(LN-3-1)has a high specific surface area(1289 m^2 g^-1),a large pore volume(2.80 cm^3 g^-1),and a well-connected and stable structure.LN-3-1 exhibits extremely high activity and stability in acidic medium for oxygen reduction reaction(ORR),superior to Pt/C catalyst and most non noble-metal catalysts reported in recent literatures.The prepared carbon material was used as a cathode catalyst to assemble a H2-O2 single fuel cell,and its excellent catalytic performance has been confirmed with the maximum power density of 779 mW cm^-2,which is one of the highest power densities among non-metallic catalysts so far.Density functional theory(DFT)calculations indicate that the synergy of chlorine and nitrogen reconciles the intermediate adsorption energies,leading to an appropriate theoretical ORR onset potential.We develop a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in proton-exchange membrane fuel cells.展开更多
Recovering valuable metals from spent lithium-ion batteries(LIBs)for high value-added application is beneficial for global energy cycling and environmental protection.In this work,we obtain the high-performance N-dope...Recovering valuable metals from spent lithium-ion batteries(LIBs)for high value-added application is beneficial for global energy cycling and environmental protection.In this work,we obtain the high-performance N-doped Ni-Co-Mn(N-NCM)electrocatalyst from waste LIBs,for robust oxygen evolution application.Lithium-rich solution and NCM oxides are effectively separated from ternary cathode materials by sulfation roasting and low-temperature water leaching approach,in which the recovery efficiency of Li metal reaches nearly 100%.By facile NH_(3)treatment,the incorporation of N into NCM significantly increases the ratio of low-valence state Co^(2+)and Mn^(2+),and the formed Mn-N bond benefits the surface catalytic kinetics.Meanwhile,the N doping induces lattice expansion of the NCM,triggering tensile stress to favor the adsorption of the reactant.Thus,the optimized N-NCM electrocatalyst exhibits the superior overpotentials of 256 and 453 mV to achieve the current density of 10 and 100 mA/cm^(2),respectively,with a low Tafel slope of 37.3 mV/dec.This work provides a fresh avenue for recycling spent LIBs in the future to achieve sustainable development.展开更多
To accelerate the kinetics of oxygen evolution reaction(OER)regarding the energy conversion and storage approaches,the discovery of desirable cost-effective and highly efficient electrocatalysts is of prime importance...To accelerate the kinetics of oxygen evolution reaction(OER)regarding the energy conversion and storage approaches,the discovery of desirable cost-effective and highly efficient electrocatalysts is of prime importance.This study demonstrates a layered CaCo_2O_4with a two-dimensional nanoplate structure,which possesses electrocatalytic activity for OER.The OER activity was achieved on CaCo_2O_4with a Tafel slope of 71 mV dec^(-1)and a current density of 10 mA cm^(-2)at an overpotential of 371 mV,which was more active than the similar structure LiCoO_2catalyst.Combined with X-ray absorption fine structure and density functional theory calculations,the enhanced OER activity and stability are mainly attributed to the unique electronic structure derived from the interaction of Ca and Co,and improved electrical conductivity.CaCo_2O_4can be developed as a highly active and earth-abundant catalyst for OER in energy conversion and storage technologies.展开更多
For the sake of accelerating the commercial application of fuel cells, non-noble metal catalysts with high activity and high stability have been widely developed to replace platinum-based catalysts. Here, we report a ...For the sake of accelerating the commercial application of fuel cells, non-noble metal catalysts with high activity and high stability have been widely developed to replace platinum-based catalysts. Here, we report a simple but cost-effective synthetic strategy using iron tetra-amino phthalocyanine(FePC-NH_2)and modified carbon black(HCB) to obtain a novel oxygen reduction electrocatalyst(named as FePCNH_2/HCB-800) with Fe_2O_3 wrapped in nitrogen-doped carbon(N-carbon) as active site. The HCB as template can effectively promotes the formation of Fe_2O_3 active site in the catalysts. Compared to commercial Pt/C catalyst, the Fe PC-NH_2/HCB-800 catalyst exhibits high electrocatalytic activity for oxygen reduction reaction(ORR) with onset potential of 0.98 V and half-wave potential with 0.84 V vs. reversible hydrogen electrode(RHE). Meanwhile, the catalyst also shows excellent circulation stability. We believe that this work provides a platform for ORR and is conducive to the commercialization of fuel cells and metal-air batteries.展开更多
Renewable lignin used for synthesizing materials has been proven to be highly potential in specific electrochemistry.Here,we report a simple method to synthesize nitrogen and sulfur co-doped carbon nanosheets by using...Renewable lignin used for synthesizing materials has been proven to be highly potential in specific electrochemistry.Here,we report a simple method to synthesize nitrogen and sulfur co-doped carbon nanosheets by using bagasse lignin,denoted as lignin-derived carbon(LC).By adjusting the ratio of nitrogen source and annealing temperature,we obtained the ultrathin graphitic lignin carbon(LC-4-1000)with abundant wrinkles with high surface area of 1208 m2g_1 and large pore volume of 1.40 cm3g_1.In alkaline medium,LC-4-1000 has more positive half-wave potential and nearly current density compared to commercial Pt/C for oxygen reduction reaction(ORR).More importantly,LC-4-1000 also exhibits comparable activity and superior stability for ORR in acid medium due to its high graphitic N ratio and a direct four electron pathway for ORR.This study develops a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in fuel cells.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.22120230104).
文摘High-entropy alloy(HEA)nanoparticles(NPs)have attracted great attention in electrocatalysis due to their tailorable complex compositions and unique properties.Herein,we introduce Fe,Co,Ni,Cr and Mn into the metal-polyphenol coordination system to prepare HEA NPs enclosed in N-doped carbon(FeCoNiCrMn)with great potential for catalyzing oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).The unique high-entropy structural characteristics in FeCoNiCrMn facilitate effective interplay between metal species,leading to improved ORR(E_(1/2)=0.89 V)and OER(η=330 mV,j=10 mA·cm^(−2))activity.Additionally,FeCoNiCrMn exhibits excellent open-circuit voltage(1.523 V),power density(110 mW·cm^(−2))and long-term durability,outperforming Pt/C+IrO_(2) electrodes as a cathode catalyst in Zn-air batteries(ZABs).Such polyphenol-assisted alloying method broadens and simplifies the development of HEA electrocatalysts for high-performance ZABs.
基金supported by the National Natural Science Foundation of China(NSFC,No.21774045)。
文摘Rational design of complex hollow nanostructures offers a great opportunity to construct various functional nanostructures.A novel in situ disassembly-polymerization-pyrolysis approach was developed to synthesize atomically dispersed Fe single atoms(Fe SAs)and tiny Co nanoparticles(Co NPs)binary sites embedded in double-shelled hollow carbon nanocages(Co NPs/Fe SAs DSCNs)without removing excess templates.The Co NPs/Fe SAs DSCNs displayed excellent bifunctional activity,boosting the realistic rechargeable zinc-air batteries with high efficiency,long-term durability,and reversibility,which is comparable to noble metal catalysts(Pt/C and RuO_(2)).The enhanced catalytic activity should be attributed to as well as the strong interactions between Fe SAs and Co NPs with the nitrogen-doped carbon matrix,the exposure of more active sites,and the high-flux mass transportation.In addition,the confinement effect between the double C–N shells prevented the aggregation and corrosion of metal atoms,thus improving the durability of the Co NPs/Fe SAs DSCNs,further highlighting the structural advantages of carbon nanoreactor.This work provides guidance for further rational design and preparation of complex hollow structure materials with advanced bifunctional air cathodes.
基金This work is supported by the National Natural Science Foundation of China(22075092)the Program for HUST Academic Frontier Youth Team(2018QYTD15).
文摘Oxygen electrocatalysts are of great importance for the air electrode in zinc-air batteries(ZABs).Owing to the high specific surface area,controllable pore size and unsaturated metal active sites,metal-organic frameworks(MOFs)derivatives have been widely studied as oxygen electrocatalysts in ZABs.To date,many strategies have been developed to generate efficient oxygen electrocatalysts from MOFs for improving the performance of ZABs.In this review,the latest progress of the MOF-derived non-noble metal-oxygen electrocatalysts in ZABs is reviewed.The performance of these MOF-derived catalysts toward oxygen reduction,and oxygen evolution reactions is discussed based on the categories of metal-free carbon materials,single-atom catalysts,metal cluster/carbon composites and metal compound/carbon composites.Moreover,we provide a comprehensive overview on the design strategies of various MOF-derived non-noble metal-oxygen electrocatalysts and their structure-performance relationship.Finally,the challenges and perspectives are provided for further advancing the MOF-derived oxygen electrocatalysts in ZABs.
基金This work is supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Centre Québéco is sur les Materiaux Fonctionnels(CQMF),Fonds de Recherche du Québec-Nature et Technologies(FRQNT)+2 种基金Institut National de la Recherche Scientifique(INRS)This work is also supported by the National Natural Science Foundation of China(21972017)the“Scientific and Technical Innovation Action Plan”Hong Kong,Macao and Taiwan Science&Technology Cooperation Project of Shanghai Science and Technology Committee(19160760600).F.Dong gratefully acknowledges scholarships from the China Scholarship Council(CSC).
文摘Rechargeable zinc-air batteries(ZABs)are currently receiving extensive attention because of their extremely high theoretical specific energy density,low manufacturing costs,and environmental friendliness.Exploring bifunctional catalysts with high activity and stability to overcome sluggish kinetics of oxygen reduction reaction and oxygen evolution reaction is critical for the development of rechargeable ZABs.Atomically dispersed metal-nitrogen-carbon(M-N-C)catalysts possessing prominent advantages of high metal atom utilization and electrocatalytic activity are promising candidates to promote oxygen electrocatalysis.In this work,general principles for designing atomically dispersed M-N-C are reviewed.Then,strategies aiming at enhancing the bifunctional catalytic activity and stability are presented.Finally,the challenges and perspectives of M-N-C bifunctional oxygen catalysts for ZABs are outlined.It is expected that this review will provide insights into the targeted optimization of atomically dispersed M-N-C catalysts in rechargeable ZABs.
基金supported financially by the National Natural Science Foundation of China,China(Grant No.51702180,51572136,91963113,21703116,51372127,51873096)The Scientific and Technical Development Project of Qingdao,China(Grant No.18-2-2-52-jch)+1 种基金The Taishan Scholar Advantage and Characteristic Discipline Team of Eco Chemical Process and TechnologyThe Natural Science Foundation of Hebei Province(B2019204009)。
文摘Efficient bifunctional oxygen electrocatalysts for ORR and OER are fundamental to the development of high performance metal-air batteries.Herein,a facile cost-efficient two-step pyrolysis strategy for the fabrication of a bifunctional oxygen electrocatalyst has been proposed.The efficient non-preciousmetal-based electrocatalyst,Fe/Fe_(3)C@Fe-N_(x)-C consists of highly curved onion-like carbon shells that encapsulate Fe/Fe_(3)C nanoparticles,distributed on an extensively porous graphitic carbon aerogel.The obtained Fe/Fe_(3)C@Fe-N_(x)-C aerogel exhibited superb electrochemical activity,excellent durability,and high methanol tolerance.The experimental results indicated that the assembly of onion-like carbon shells with encapsulated Fe/Fe_(3)C yielded highly curved carbon surfaces with abundant Fe-Nxactive sites,a porous structure,and enhanced electrocatalytic activity towards ORR and OER,hence displaying promising potential for application as an air cathode in rechargeable Zn-air batteries.The constructed Zn-air battery possessed an exceptional peak power density of~147 mW cm^(-2),outstanding cycling stability(200 cycles,1 h per cycle),and a small voltage gap of 0.87 V.This study offers valuable insights regarding the construction of low-cost and highly active bifunctional oxygen electrocatalysts for efficient air batteries.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2022ME218)the National Natural Science Foundation of China(Nos.52102260,52171211 and 52202243)China Postdoctoral Science Foundation(Nos.2022M711545 and 2022M711371)。
文摘Designing rational transition-metal/carbon composites with highly dispersed and firmly anchored nanoparticles(NPs)to prevent agglomeration and shedding is crucial for realizing excellent electrocatalytic performances.Herein,a biomass pore-confined strategy based on mesoporous willow catkin is explored to obtain uniformly dispersed CoFe NPs in N-doped carbon nanotubes and hollow carbon fibers(CoFe@N-CNTs/HCFs).The resultant catalyst exhibits enhanced electrocatalytic performance,which affords a half-wave potential of 0.86 V(vs.RHE)with a limited current density of 6.0 mA·cm^(-2)for oxygen reduction reaction and potential of 1.67 V(vs.RHE)at 10 mA·cm^(-2)in 0.1 M KOH for oxygen evolution reaction.When applied to rechargeable zinc-air batteries,a maximum power density of 340 mW·cm^(-2)and long-term cyclic durability over 800 h are achieved.Such superior bifunctional electrocatalytic activities are ascribed to the biocarbon matrix with abundant mesopores and unobstructed hollow channels,CoFe NPs with high dispersion and controllable nanoscale and the hybrid composite with optimized electronic structure.This work presents an effective approach for constraining the size and dispersion of NPs in a low-cost biocarbon substrate,offering valuable insights for designing advanced oxygen electrocatalysts.
基金supported by the National Science Foundation of China(21805235)the Opening Foundation of Creative Platform of the Key Laboratory of the Education Department of Hunan Province(20K131)the Construct Program of the Key Discipline in Hunan Province。
文摘Rational design and exploration of low-cost and robust bifunctional oxygen electrocatalysts are vitally important for developing high-performance zinc-air batteries(ZABs).Herein,we reported a facile yet cost-efficient approach to construct a bifunctional oxygen reduction reaction(ORR)/oxygen evolution reaction(OER)electrocatalyst composed of N-doped porous carbon nanosheet flowers decorated with Fe Co nanoparticles(Fe Co/N-CF).Rational design of this catalyst is achieved by designing Schiff-base polymer with unique molecular structure via hydrogen bonding of cyanuramide and terephthalaldehyde polycondensate in the presence of metal cations.It exhibits excellent activity and stability for electrocatalysis of ORR/OER,enabling ZAB with a high peak power density of 172 m W cm^(-2)and a large specific capacity of 811 m A h g^(-1)Znat large current.The rechargeable ZAB demonstrates excellent durability for 1000 h with slight voltage decay,far outperforming a couple of precious Pt/Ir-based catalysts.Density functional theory(DFT)calculations reveal that high activity of bimetallic Fe Co stems from enhanced O_(2)and OH-adsorption and accelerated O_(2)dissociation by OAO bond activation.
基金supported by National Natural Science Foundation of China(52302235,52462013)Distinguished Young Scholars of Anhui Provincial Department of Education Research Plan(2022AH020068)+4 种基金Excellent Young Scholars of Anhui Provincial Department of Education Research Plan(2024AH030037)Excellent Young Teacher Training Program of Anhui(YQZD2024024)China Postdoctoral Science Foundation(2023M730891)Natural Science Foundation of Hainan Province(224QN185)State Key Laboratory of Heavy Oil Processing(SKLHOP202202009).
文摘An effective strategy of regulating active sites in bifunctional oxygen electrocatalysts is essentially desired,especially in rechargeable metal-air batteries(RZABs).Herein,a highly efficient electrocatalyst of CoFe alloys embedded in pyridinic nitrogen enriched N-doped carbon(CoFe/P-NC)is intelligently constructed by pyrolysis strategy.The high concentration of pyridinic nitrogen in CoFe/P-NC can significantly reprogram the redistribution of electron density of metal active sites,consequently optimizing the oxygen adsorption behavior.As expected,the pyridinic nitrogen guarantees CoFe/P-NC providing the low overpotential of the overall oxygen electrocatalytic process(ΔEORR-OER=0.73 V vs.RHE)and suppresses the benchmark electrocatalysts(Pt/C&RuO_(2)).Assembled rechargeable Zn-air battery using CoFe/P-NC demonstrates a promising peak power density of 172.0 mW cm^(-2),a high specific capacity of 805.0 mAh g^(-1)Zn and an excellent stability.This work proposes an interesting strategy for the design of robust oxygen electrocatalysts for energy conversion and storage fields.
基金supported by the National Key Research and Development Program of China(No.2020YFB1506002)National Natural Science Foundation of China(No.21975143).
文摘With the rapid economic growth and the deepening awareness of sustainable development,the demand for green and efficient energy storage equipment increases.As a promising energy storage and conversion device,zinc-air batteries(ZABs)have the advantages of high theoretical specific energy density,low cost,and environmental friendliness.Nevertheless,the efficiency of ZABs is closely related to the electrocatalytic capacity of the air electrode due to its sluggish kinetics for oxygen reduction and evolution reaction(ORR/OER).Therefore,it is necessary to develop efficient catalysts to promote the reaction rate.Recently,cobalt-based materials have become a research hotspot for oxygen electrocatalysts owing to their rich natural content,high catalytic activity,and stability.In this review,the mechanisms of the OER/ORR reaction process,the catalyst's performance characterization,and the various combination methods with the current collector are systematically introduced and analyzed.Further,a broad overview of cobalt-based materials used as electrocatalysts for ZABs is presented,including cobalt-based perovskite,cobalt-nitrogen-carbon(Co-N-C)materials,cobalt oxides,cobalt-containing composite oxides,and cobalt sulfides/phosphides.Finally,various strategies for developing efficient electrocatalysts for ZABs are summarized,highlighting the challenges and future perspectives in designing novel catalysts.
基金This project was financially supported by the Ministry of Education of the people’s Republic of China(No.IRT13R30).
文摘Despite the extensive application of porous nanostructures as oxygen electrocatalysts, it is challenging to synthesize single-metal state materials with porous structures, especially the ultrasmall ones due to the uniform diffusion of the same metal. Herein, we pioneer demonstrate a new size effect-based controllable synthesis strategy for the homogeneous Co nanokarstcaves assisted by Co-CN hybrids (CCHs). The preferential migration of cobalt atoms on the surface of small size zeolitic imidazolate framework (ZIF) with high surface energy during pyrolysis is the key factor for the formation of nanokarstcave structure. Furthermore, graphene can act as a diffusion barrier to prevent the agglomeration of nanoparticles in the synthesis process, which also plays an important role in the formation of porous nanostructures. In alkali media, CCHs achieve overpotential of 287 mV (@10 mA·cm^(−2)) for oxygen evolution reaction (OER) and a half wave potential of 0.86 V (vs. RHE) for oxygen reduction reaction (ORR).
基金the financial support from the National Key Research and Development Program of China (2016YFB0700204)Natural Science Foundation of Jiangsu Province (No. BK20140472)+2 种基金NSFC (51602332, 51502327)Science and Technology Commission of Shanghai Municipality (15520720400, 15YF1413800, 14DZ2261203, 16DZ2260603)One Hundred Talent Plan of Chinese Academy of Sciences
文摘A series of N-doped carbon materials(NCs)were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile onestep pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C_3N_4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6,show the highest N content of ~6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of ~66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal–air batteries.
基金financially supported by the Key Research and Development Project of Hainan Province(No.ZDYF2022GXJS006)the National Natural Science Foundation of China(Nos.52177220 and 52231008)。
文摘Seawater battery is an advanced energy storage system that enables conversion of chemical energy to electricity by consuming metals,dissolved oxygen and seawater in anode,cathode and electrolyte,respectively.However,the oxygen reduction reaction(ORR)activity and stability of electrocatalysts can be easily deactivated due to the severe Cl~-permeation and corrosion in seawater electrolyte.Herein,we developed a structural buffer engineering strategy by spontaneously anchoring Cl~-intoα-Co(OH)_(2) as efficient and stable ORR electrocatalysts,in which the ultrathinα-Co(OH)_(2) nanosheets were synthesized using an ultrafast solution high-temperature shock(SHTS)strategy.The large lattice space(~0.8 nm)of layeredα-Co(OH)_(2) ensured the spontaneously penetration of Cl~-into the lattice structure and replaced part of OH~-to formα-Co(OH)_(2-x)Cl_x.The continuous leaching and compensating of saturated Cl inα-Co(OH)_(2-x)Cl_x could enhance the Cl~-corrosion resistance and modulate electronic structure of Co metallic sites,thus improving the ORR electrocatalytic activity and stability in seawater electrolyte.Theα-Co(OH)_(2-x)Cl_x seawater batteries display superior onset and half-wave potentials of 0.71 and 0.66 V,respectively,which are much better than the counterparts ofα-Co(OH)_(2) and ofβ-Co(OH)_(2) with no Cl~-penetrating and no buffer structure.Theα-Co(OH)_(2-x)Cl_x-based seawater batteries display stable open-circuit potential of 1.69 V and outstanding specific capacity of 1345 mAh·g^(-1).
基金financial support from the National Natural Science Foundation of China(No.21376257)the Jiangsu Provincial Natural Science Foundation of China(No.BK20131112)
文摘To develop more ideal bifunctional heteroatom-doped carbon electrocatalysts toward the oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) for regenerative fuel cells and rechargeable metal–air batteries, herein, tobacco-derived N-containing ordered mesoporous carbon(N-OMC) electrocatalysts with different N species distributions are designed. Results indicate that the as-prepared N-OMC with more pyrrolic and pyridinic Ns exhibits much higher activities for the ORR and OER than N-OMC with more graphitic N in both acidic and alkaline media, suggesting that the increase of pyrrolic and pyridinic Ns favors the improvement of ORR and OER activities of the N-containing carbon catalysts, and showing a great potential for the designing of more effective, lower-cost ORR and OER bifunctional electrocatalysts for future regenerative fuel cells and rechargeable metal–air batteries.
基金supported by the National Key Research and Development Program of China(2017YFA0206500)NSF of China(51502012+8 种基金2167602021620102007)Beijing Natural Science Foundation(2162032)The Start-up fund for talent introduction of Beijing University of Chemical Technology(buctrc201420buctrc201714)Talent cultivation of State Key Laboratory of OrganicInorganic CompositesThe Fundamental Research Funds for the Central Universities(ZD1502)Distinguished scientist program at BUCT(buctylkxj02)the“111”project of China(B14004)
文摘Developing non-precious metal catalyst with high activity, good stability and low cost for electrocatalytic oxygen reduction reaction（ORR） is critical for the wide application of energy conversion system. Here, we developed a cost–effective synthetic strategy via silica assistance to obtain a novel FeC/Fe–N–C（named as COPBP-PB-Fe-900-SiO） catalyst with effective active sites of Fe–Nand FeC from the rational design two-dimensional covalent organic polymer（COPBP-PB）. The nitrogen-rich COP effectively promotes the formation of active Fe–Nsites. Additionally, the silica not only can effectively suppress the formation of large Fe-based particles in the catalysts, but also increases the degree of carbonization of the catalyst.The as-prepared COPBP-PB-Fe-900-SiOcatalyst exhibits high electrocatalytic activity for ORR with a halfwave potential of 0.85 V vs. reversible hydrogen electrode（RHE）, showing comparable activity as compared with the commercial Pt/C catalysts in alkaline media. Moreover, this catalyst also shows a high stability with a nearly constant onset potential and half-wave potential after 10,000 cycles. The present work is highly meaningful for developing ORR electrocatalysts toward wide applications.
基金financially supported by the National Natural Science Foundation of China(Nos.21576135 and 21706129)the Youth Fund of Jiangsu Province(No.BK20150945)+2 种基金Program for Jiangsu Specially-Appointed Professorsthe Funding from State Key Laboratory of Materials-Oriented Chemical Engineering(No.ZK201808)the financial support of the Australian Research Council.
文摘The requirement for a sustainable and renewable energy has inspired substantial interests in designing and developing earth-abundant and high-effectiveness electrocatalysts/electrodes for fuel cells and metal-air batteries,in which oxygen reduction reaction(ORR)plays a crucial role.Perovskite oxides have acquired rapid attention as ORR electrocatalysts to replace noble-metal-based catalysts owing to their intrinsic electrocatalytic activity,compositional and structural flexibility.Herein,we report a new Sc and P co-doped perovskite oxide(La0.8Sr0.2Mn0.95Sc0.025P0.025O3-δ,LSMSP)as an active and robust electrocatalyst for the ORR in an alkaline solution.LSMSP electrocatalyst shows superior ORR activity and stability than those of pristine La0.8Sr0.2MnO3-δ(LSM),Sc-doped LSM and P-doped LSM due to the optimized average valence of Mn ions,the large surface area,the smaller particle size and the synergetic effect introduced by the co-doping.Moreover,compared to the benchmark Pt/C electrocatalyst,LSMSP electrocatalyst displays comparable ORR activity and superior durability.These above results suggest that the co-doping strategy of Sc and P into perovskites is a useful method to design high-performance electrocatalysts for the ORR,which can be used in other electrocatalysis-based applications.
基金the financial support from the National Natural Science Foundation of China(No.21373091)the Science and Technology Project of Guangzhou City(No.201704030040).
文摘Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy using eutectic NaCl/ZnCl2 melt as airtight and swelling agent to obtain 3D mesoporous skeleton structured carbon from renewable lignin.The prepared lignin-derived biocarbon material(LN-3-1)has a high specific surface area(1289 m^2 g^-1),a large pore volume(2.80 cm^3 g^-1),and a well-connected and stable structure.LN-3-1 exhibits extremely high activity and stability in acidic medium for oxygen reduction reaction(ORR),superior to Pt/C catalyst and most non noble-metal catalysts reported in recent literatures.The prepared carbon material was used as a cathode catalyst to assemble a H2-O2 single fuel cell,and its excellent catalytic performance has been confirmed with the maximum power density of 779 mW cm^-2,which is one of the highest power densities among non-metallic catalysts so far.Density functional theory(DFT)calculations indicate that the synergy of chlorine and nitrogen reconciles the intermediate adsorption energies,leading to an appropriate theoretical ORR onset potential.We develop a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in proton-exchange membrane fuel cells.
基金Project(2022YFC3900804)supported by the National Key Research and Development Program,ChinaProjects(2021JJ10058,2022JJ10074)supported by the Natural Science Foundation of Hunan Province of China。
文摘Recovering valuable metals from spent lithium-ion batteries(LIBs)for high value-added application is beneficial for global energy cycling and environmental protection.In this work,we obtain the high-performance N-doped Ni-Co-Mn(N-NCM)electrocatalyst from waste LIBs,for robust oxygen evolution application.Lithium-rich solution and NCM oxides are effectively separated from ternary cathode materials by sulfation roasting and low-temperature water leaching approach,in which the recovery efficiency of Li metal reaches nearly 100%.By facile NH_(3)treatment,the incorporation of N into NCM significantly increases the ratio of low-valence state Co^(2+)and Mn^(2+),and the formed Mn-N bond benefits the surface catalytic kinetics.Meanwhile,the N doping induces lattice expansion of the NCM,triggering tensile stress to favor the adsorption of the reactant.Thus,the optimized N-NCM electrocatalyst exhibits the superior overpotentials of 256 and 453 mV to achieve the current density of 10 and 100 mA/cm^(2),respectively,with a low Tafel slope of 37.3 mV/dec.This work provides a fresh avenue for recycling spent LIBs in the future to achieve sustainable development.
基金supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA02040600)supported by the Canadian Foundation for Innovation+5 种基金Natural Sciences and Engineering Research Council of Canadathe University of Saskatchewanthe Government of SaskatchewanWestern Economic Diversification Canadathe National Research Council Canadathe Canadian Institutes of Health Research
文摘To accelerate the kinetics of oxygen evolution reaction(OER)regarding the energy conversion and storage approaches,the discovery of desirable cost-effective and highly efficient electrocatalysts is of prime importance.This study demonstrates a layered CaCo_2O_4with a two-dimensional nanoplate structure,which possesses electrocatalytic activity for OER.The OER activity was achieved on CaCo_2O_4with a Tafel slope of 71 mV dec^(-1)and a current density of 10 mA cm^(-2)at an overpotential of 371 mV,which was more active than the similar structure LiCoO_2catalyst.Combined with X-ray absorption fine structure and density functional theory calculations,the enhanced OER activity and stability are mainly attributed to the unique electronic structure derived from the interaction of Ca and Co,and improved electrical conductivity.CaCo_2O_4can be developed as a highly active and earth-abundant catalyst for OER in energy conversion and storage technologies.
基金supported by the National Key Research and Development Program of China (2017YFA0206500)The National Natural Science Foundation (NSF) of China (51502012, 21676020)+6 种基金Beijing Natural Science Foundation (2162032, 17L20060)Young Elite Scientists Sponsorship Program by CAST (2017QNRC001)The Start-Up Fund for Talent Introduction of Beijing University of Chemical Technology (BUCTRC201420 BUCTRC201714)Talent Cultivation of State Key Laboratory of Organic-Inorganic Composites Distinguished Scientist Program at BUCT (buctylkxj02)the "111" Project of China (B14004)
文摘For the sake of accelerating the commercial application of fuel cells, non-noble metal catalysts with high activity and high stability have been widely developed to replace platinum-based catalysts. Here, we report a simple but cost-effective synthetic strategy using iron tetra-amino phthalocyanine(FePC-NH_2)and modified carbon black(HCB) to obtain a novel oxygen reduction electrocatalyst(named as FePCNH_2/HCB-800) with Fe_2O_3 wrapped in nitrogen-doped carbon(N-carbon) as active site. The HCB as template can effectively promotes the formation of Fe_2O_3 active site in the catalysts. Compared to commercial Pt/C catalyst, the Fe PC-NH_2/HCB-800 catalyst exhibits high electrocatalytic activity for oxygen reduction reaction(ORR) with onset potential of 0.98 V and half-wave potential with 0.84 V vs. reversible hydrogen electrode(RHE). Meanwhile, the catalyst also shows excellent circulation stability. We believe that this work provides a platform for ORR and is conducive to the commercialization of fuel cells and metal-air batteries.
基金financial support from the National Natural Science Foundation of China (Nos. 21476089, 21373091)the Provincial Science and Technology Project of Guangdong (No. 2014A030312007)
文摘Renewable lignin used for synthesizing materials has been proven to be highly potential in specific electrochemistry.Here,we report a simple method to synthesize nitrogen and sulfur co-doped carbon nanosheets by using bagasse lignin,denoted as lignin-derived carbon(LC).By adjusting the ratio of nitrogen source and annealing temperature,we obtained the ultrathin graphitic lignin carbon(LC-4-1000)with abundant wrinkles with high surface area of 1208 m2g_1 and large pore volume of 1.40 cm3g_1.In alkaline medium,LC-4-1000 has more positive half-wave potential and nearly current density compared to commercial Pt/C for oxygen reduction reaction(ORR).More importantly,LC-4-1000 also exhibits comparable activity and superior stability for ORR in acid medium due to its high graphitic N ratio and a direct four electron pathway for ORR.This study develops a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in fuel cells.
