Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal s...Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency.展开更多
Aniline,pyrrole and phenanthroline,which have different nitrogen compositions,are used as carbon precursors to synthesize nitrogen-doped ordered mesoporous carbons（NOMCs） by the nanocasting method.The effect of the ...Aniline,pyrrole and phenanthroline,which have different nitrogen compositions,are used as carbon precursors to synthesize nitrogen-doped ordered mesoporous carbons（NOMCs） by the nanocasting method.The effect of the precursor on the resultant NOMC is extensively investigated by nitrogen adsorption-desorption measurements,scanning electron microscopy,X-ray photoelectron spectroscopy（XPS）,cyclic voltammetry and rotating ring-disk electrode measurements.Salient findings are as follows.First,the precursor has a significant influence on the specific surface area and textural properties.The NOMC materials derived from pyrrole（C-PY-900：765 m^2/） and phenanthroline（C-Phen-900：746 m^2/） exhibit higher specific surface areas than the aniline analog（C-PA-900：569 m^2/）.Second,the XPS results indicate that the total nitrogen content（ca.3.1–3.3 at%） is similar for the three carbon sources,except for a slight difference in the nitrogen configuration.Furthermore,the content of the nitrogen-activated carbon atoms is found to closely depend on the precursor,which is the highest for the phenanthroline-derived carbon.Third,the electrochemical results reveal that the electrocatalytic activity follows in the order C-PA-900 C-PY-900 C-Phen-900,confirming that the nitrogen-activated carbon atoms are the active sites for the oxygen reduction reaction（ORR）.In summary,the precursor has considerable influence on the composition and textural properties of the NOMC materials,of which the ORR electrocatalytic activity can be enhanced through optimization of the NOMCs.展开更多
Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overco...Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overcome its slow reaction kinetic always undergo a complex dynamic evolution in the actual catalytic process,and the concomitant intermediates and catalytic products also occur continuous conversion and reconstruction.This makes them difficult to be accurately captured,making the identification of ORR active sites and the elucidation of ORR mechanisms difficult.Thus,it is necessary to use extensive in-situ characterization techniques to proceed the real-time monitoring of the catalyst structure and the evolution state of intermediates and products during ORR.This work reviews the major advances in the use of various in-situ techniques to characterize the catalytic processes of various catalysts.Specifically,the catalyst structure evolutions revealed directly by in-situ techniques are systematically summarized,such as phase,valence,electronic transfer,coordination,and spin states varies.In-situ revelation of intermediate adsorption/desorption behavior,and the real-time monitoring of the product nucleation,growth,and reconstruction evolution are equally emphasized in the discussion.Other interference factors,as well as in-situ signal assignment with the aid of theoretical calculations,are also covered.Finally,some major challenges and prospects of in-situ techniques for future catalysts research in the ORR process are proposed.展开更多
metal oxide electronic interactions in composite electrocatalysts have a considerable impact on their catalytic capability.In this study,we successfully synthesized an electrocatalytic material composed of MoO_(3)/C s...metal oxide electronic interactions in composite electrocatalysts have a considerable impact on their catalytic capability.In this study,we successfully synthesized an electrocatalytic material composed of MoO_(3)/C speciessupported Pd nanoparticles(Pd-MoO_(3)/C)using a convenient hydrothermal method,which exhibited excellent catalytic activities for both ethanol oxidation and oxygen reduction in KOH media.The specific activity of PdMoO_(3)/C toward ethanol oxidation with MoO_(3)loading(40wt%)was~2.6 times greater than that for the commercial Pd/C(10 wt%)with the same Pd content.In particular,the activity could effectively hold up to~60%of its maximum activity after 500-cycle tests,demonstrating improved cyclical stability.Notably,the fast electron transfer kinetics toward oxygen reduction for Pd-MoO_(3)/C(40%)were also comparable to those of commercial Pt/C(20 wt%)catalysts.These superior electrochemical features are primarily derived from the stronger electronic coupling between Pd and MoO_(3)through charge transfer,which can supply more active centers and improve the anti-poisoning ability.Meanwhile,the MoO_(3)species in the Pd-MoO_(3)/C composite may provide additional benefits in terms of electrical conductivity and dispersion.展开更多
The electrochemical nitrogen reduction reaction(NRR)to directly produce NH3 from N_(2) and H_(2)O under ambient conditions has attracted significant attention due to its ecofriendliness.Nevertheless,the electrochemica...The electrochemical nitrogen reduction reaction(NRR)to directly produce NH3 from N_(2) and H_(2)O under ambient conditions has attracted significant attention due to its ecofriendliness.Nevertheless,the electrochemical NRR presents several practical challenges,including sluggish reaction and low selectivity.Here,bi-atom catalysts have been proposed to achieve excellent activity and high selectivity toward the electrochemical NRR by Ma and his co-workers.It could accelerate the kinetics of N_(2)-to-NH_(3) electrochemical conversion and possess better electrochemical NRR selectivity.This work sheds light on the introduction of bi-atom catalysts to enhance the performance of the electrochemical NRR.展开更多
Studies have extensively addressed the development of electrocatalytic technologies for energy storage and conversion,fuel production,and environmental protection.Electrode processes such as different oxidation and re...Studies have extensively addressed the development of electrocatalytic technologies for energy storage and conversion,fuel production,and environmental protection.Electrode processes such as different oxidation and reduction reactions play a vital and significant role in these technologies.In this regard,efficient,inexpensive,and stable electrocatalysts capable can significantly promote electrochemical reactions.Unique features of metal–organic frameworks(MOFs)such as their high porosity,tunable structure,size,and pore shape,high surface area,and redox properties have introduced them as an ideal electrocatalyst candidate.This review is thus aimed at elucidating the role of MOF-based materials(pristine,derivatives and composites)as efficient electrocatalysts in energy and sensing-related oxidation and reduction reactions such as oxygen reduction reaction(ORR),hydrogen oxidation reaction(HOR),carbon dioxide reduction reaction(CO_(2)RR),urea oxidation reaction(UOR),alcohol oxidation reaction(AOR),nitrogen reduction reaction(NRR),and glucose oxidation reaction(GOR)in advanced energy and sensing devices.Also,the structure–property relationship of the electrocatalyst was elaborated for each electrocatalytic reaction.Finally,perspectives on the potential research topics for practical use of MOF-based electrocatalysts are addressed.The present review can improve the interest in MOF-based electrocatalysts to study different oxidation and reduction reactions in energy and sensing systems.展开更多
The pyrolysis under inert atmosphere has been widely used for the synthesis of metal containing heteroatoms doped carbon materials, versatile catalysts for various reactions. However, it is difficult to prevent metal ...The pyrolysis under inert atmosphere has been widely used for the synthesis of metal containing heteroatoms doped carbon materials, versatile catalysts for various reactions. However, it is difficult to prevent metal nanoparticles aggregation during pyrolysis process. Herein, we reported the efficient synthesis of nitrogen doped carbon hollow nanospheres with cobalt nanoparticles （Co NP, ca. 10nm in size） distributed uniformly in the shell via pyrolysis of yolk-shell structured Zn-Co-ZIFs@polydopamine （PDA）. PDA acted as both protection layer and carbon source, which successfully prevented the aggregation of cobalt nanoparticles during high-temperature pyrolysis process. The Co NP and N containing carbon （Co NP/NC） hollow nanospheres were active for both oxygen evolution reaction （OER） and oxygen reduction reaction （ORR）, affording overpotential of 430 mV at 10 mA/cm2 for OER in 1 M KOH and comparable half-wave potential to that of Pt/C （0.80V vs RHE） for ORR in 0.1 M KOH. The superior performance of carbon hollow nanospheres for both OER and ORR was mainly attributed to its small metal nanoparticles, N-doping and hollow nanostructure. The protection and confinement effect that originated from PDA coating strategy could be extended to the synthesis of other hollow structured carbon materials, especially the ones with small metal nanoparticles.展开更多
To replace precious metal oxygen reduction reaction(ORR)electrocatalysts,many transition metals and N-doped car-bon composites have been proposed in the last decade resulting in their rapid development as promising no...To replace precious metal oxygen reduction reaction(ORR)electrocatalysts,many transition metals and N-doped car-bon composites have been proposed in the last decade resulting in their rapid development as promising non-precious metal catalysts.We used Ketjenblack carbon as the precursor and mixed it with a polymeric ionic liquid(PIL)of[Hvim]NO_(3) and Fe(NO_(3))_(3),which was thermally calcined at 900℃ to produce a porous FeO_(x),N co-doped carbon material denoted FeO_(x)-N/C.Because the PIL of[Hvim]NO_(3) strongly combines with and disperses Fe^(3+)ions,and NO_(3)−is thermally pyrolyzed to form the porous structure,the FeO_(x)-N/C catalyst has a high electrocatalytic activity for the ORR in both 0.1 mol L^(−1) KOH and 0.5 mol L^(−1) H_(2)SO_(4) electrolytes.It was used as the catalyst to assemble a zinc-air battery,which had a peak power density of 185 mW·cm^(−2).Its superior electrocatalytic activity,wide pH range,and easy preparation make FeO_(x)-N/C a promising electrocatalyst for fuel cells and metal-air batteries.展开更多
Electrocatalytic reduction reactions,powered by clean energy sources such as solar energy and wind,offer a sustainable method for converting inexpensive feedstocks(e.g.,CO_(2),N_(2)/NO_(x),organics,and O_(2))into high...Electrocatalytic reduction reactions,powered by clean energy sources such as solar energy and wind,offer a sustainable method for converting inexpensive feedstocks(e.g.,CO_(2),N_(2)/NO_(x),organics,and O_(2))into high-value-added chemicals or fuels.The design and modification of electrocatalysts have been widely implemented to improve their performance in these reactions.However,bottle-necks are encountered,making it challenging to further improve performance through catalyst development alone.Recently,cations in the electrolyte have emerged as critical factors for tuning both the activity and product selectivity of reduction reactions.This review summarizes recent advances in understanding the role of cation effects in electrocatalytic reduction reactions.First,we introduce the mechanisms underlying cation effects.We then provide a comprehensive overview of their application in electroreduction reactions.Characterization techniques and theoretical calcula-tion methods for studying cation effects are also discussed.Finally,we address remaining challeng-es and future perspectives in this field.We hope that this review offers fundamental insights and design guidance for utilizing cation effects,thereby advancing their development.展开更多
Oxygen evolution and oxygen reduction are considered as essential processes in the energy conversion devices.The progress of cost-effective bifunctional catalysts has become a critical issue to be solved.Here,we repor...Oxygen evolution and oxygen reduction are considered as essential processes in the energy conversion devices.The progress of cost-effective bifunctional catalysts has become a critical issue to be solved.Here,we report that Co(OH)_(2)@N-doped carbon(NC)was facilely synthesized through the impregnation strategy of metal-organic frameworks derived carbon and cobalt ions.N-doped carbon with porous structure and cobalt hydroxide nanosheets play a synergistic effect role,representing excellent catalytic performance toward oxygen evolution and reduction reactions.The obtained Co(OH)_(2)@NC exhibits remarkable activity in terms of a lower overpotential of 330 mV@10 mA cm^(-2) for OER and a more positive half-wave potential(E_(1/2)=0.84 V)for ORR in alkaline medium,outperforming IrO_(2) and Pt/C.Due to its superior bifunctional catalytic performance,Co(OH)_(2)@NC catalyst is applied into a promising air electrode of Zn-air battery.This presented strategy of impregnation synthesis in this work provides a new design direction for practical electrochemical energy devices.展开更多
The rotating disk electrode technique is commonly used for screening and characterizing the performance of electrocatalysts for the oxygen reduction reaction(ORR).However,a reliable performance comparison of different...The rotating disk electrode technique is commonly used for screening and characterizing the performance of electrocatalysts for the oxygen reduction reaction(ORR).However,a reliable performance comparison of different electrocatalysts from different labs remains a challenge because of the inconsistency in the measurement of commercial Pt/C.Commercial Pt/C has been adopted extensively as a reference for evaluating the ORR performance of a new electrocatalyst.However,the reported ORR performances of commercial Pt/C from different labs could be significantly different because of multiple factors.Herein,we conducted a meta‐analysis of the ORR performance of commercial Pt/C via data mining of the literature.This revealed the optimal testing conditions for the most repeatable ORR performance,with commercial Pt/C in both acid and alkaline electrolytes;the optimal Pt loading was 20μg/cm^(2) on a 4 mm glassy carbon working electrode.The value of 0.84±0.03 V was suggested as the“Golden reference”of the commercial Pt/C(with Pt 20 wt%)ORR half‐wave potential for the performance evaluation of other ORR catalysts in both acid and alkaline electrolytes.The conclusion obtained through the meta‐analysis was confirmed by experiments.This study provides general guidance for a reliable measurement of the ORR performance of commercial Pt/C as a reference.展开更多
Hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)relying on high-performance and low-cost single-atom catalysts(SACs)driven by renewable energy sources offer a sustainable route to carbo...Hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)relying on high-performance and low-cost single-atom catalysts(SACs)driven by renewable energy sources offer a sustainable route to carbon-neutral chemicals and fuels.Herein,first-principles calculations were performed to investigate the catalytic HER/OER/ORR activity of a novel graphitic carbon nitride monolayer(g-C_(7)N_(3))supported single transition metal(TM@g-C_(7)N_(3)).High stability as well as positively charged active site(TM-site)and desirable electrical conductivity lay the foundation for TM@g-C_(7)N_(3)acting as efficient HER/OER/ORR electrocatalysts.We screened out the non-noble-metal Rh@g-C_(7)N_(3)SAC exhibiting great potential as the trifunctional electrocatalysts for water splitting(η^(HER)=0.06 V andηOER=0.46 V)and a metal-air battery(η^(ORR)=0.28 V)on both kinetic and thermodynamic scales,whereas the Ni@g-C_(7)N_(3)can be served as a bifunctional OER/ORR catalyst with a low overpotential of 0.33 V/0.31 V,for both of which the high thermodynamic stability and oxidation barrier guarantee their outstanding performances at ambient conditions.The mechanism analysis indicates the filling of d-orbital electrons of TM-atom can play an important role in determining the value of an energy descriptor(ΔGOH*),and the suitableΔGOH*values make for the TM@g-C_(7)N_(3)candidates to possess favorable OER/ORR overpotential.Particularly,the Rh-d orbital of Rh@g-C_(7)N_(3)is evidently hybridized with the OH*-p orbital,resulting in the lone electrons initially distributed in the antibonding orbital pairing up and occupying the downward bonding orbital,ensuring OH*can be adsorbed on Rh@g-C_(7)N_(3)appropriately.Moreover,multiple-level descriptors including d-band center,COHP,Nd,andφare used to reveal the origin of the electrocatalytic activity.展开更多
Development of high-efficiency bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts is vital for the widespread application of zinc-air batteries(ZABs).However,it still remains...Development of high-efficiency bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts is vital for the widespread application of zinc-air batteries(ZABs).However,it still remains a great challenge to avoid the inhomogeneous distribution and aggregation of metal single-atomic active centers in the construction of bifunctional electrocatalysts with atomically dispersed multimetallic sites because of the common calcination method.Herein,we report a novel catalyst with phthalocyanine-assembled Fe-Co-Ni single-atomic triple sites dispersed on sulfur-doped graphene using a simple ultrasonic procedure without calcination,and X-ray absorption fine structure(XAFS),aberration-corrected scanning transmission electron microscopy(AC-STEM),and other detailed characterizations are performed to demonstrate the successful synthesis.The novel catalyst shows extraordinary bifunctional ORR/OER activities with a fairly low potential difference(ΔE=0.621 V)between the OER overpotential(Ej10=315 mV at 10 m A cm^(-2))and the ORR half-wave potential(Ehalf-wave=0.924 V).Moreover,the above catalyst shows excellent ZAB performance,with an outstanding specific capacity(786 mAh g^(-1)),noteworthy maximum power density(139 mW cm^(-2)),and extraordinary rechargeability(discharged and charged at 5 mA cm^(-2) for more than 1000 h).Theoretical calculations reveal the vital importance of the preferable synergetic coupling effect between adjacent active sites in the Fe-Co-Ni trimetallic single-atomic sites during the ORR/OER processes.This study provides a new avenue for the investigation of bifunctional electrocatalysts with atomically dispersed trimetallic sites,which is intended for enhancing the ORR/OER performance in ZABs.展开更多
High entropy alloys(HEAs)have gained significant attention in electrocatalysis research due to their distinctive multi-element composition,intricate electronic structure,and superior properties.By harnessing multi-com...High entropy alloys(HEAs)have gained significant attention in electrocatalysis research due to their distinctive multi-element composition,intricate electronic structure,and superior properties.By harnessing multi-component synergy,precise electron regulation,and the high-entropy effect,HEA electrocatalysts exhibit remarkable catalytic activity,selectivity,and stability.These materials demonstrate outstanding catalytic performance in a variety of electrocatalytic small molecule reduction reactions,including oxygen reduction(ORR),hydrogen evolution(HER),and CO_(2)reduction(CO_(2)RR),making them promising candidates for clean energy conversion and storage applications,including fuel cells,metal-air batteries,water electrolysis,and CO_(2)conversion technologies.This review highlights recent advancements in HEA electrocatalyst research,focusing on their synthesis,characterization,and applications in electrocatalytic small molecule reduction reactions.It also explores the underlying mechanisms of the high-entropy effect,multi-component synergy,and structural design.Finally,it discusses key challenges that remain in the application of HEAs for electrocatalytic small molecule reduction and outlines potential directions for future development in this field.展开更多
Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespr...Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespread attention for CO_(2)RR due to their high catalytic activity,selectivity,excellent stability,and low cost.However,they still need to be further improved to meet the needs of industrial applications.This review article comprehensively summarizes the recent advances in regulation strategies of Bi-based catalysts and can be divided into six categories:(1)defect engineering,(2)atomic doping engineering,(3)organic framework engineering,(4)inorganic heterojunction engineering,(5)crystal face engineering,and(6)alloying and polarization engineering.Meanwhile,the corresponding catalytic mechanisms of each regulation strategy will also be discussed in detail,aiming to enable researchers to understand the structure-property relationship of the improved Bibased catalysts fundamentally.Finally,the challenges and future opportunities of the Bi-based catalysts in the photoelectrocatalytic CO_(2)RR application field will also be featured from the perspectives of the(1)combination or synergy of multiple regulatory strategies,(2)revealing formation mechanism and realizing controllable synthesis,and(3)in situ multiscale investigation of activation pathways and uncovering the catalytic mechanisms.On the one hand,through the comparative analysis and mechanism explanation of the six major regulatory strategies,a multidimensional knowledge framework of the structure-activity relationship of Bi-based catalysts can be constructed for researchers,which not only deepens the atomic-level understanding of catalytic active sites,charge transport paths,and the adsorption behavior of intermediate products,but also provides theoretical guiding principles for the controllable design of new catalysts;on the other hand,the promising collaborative regulation strategies,controllable synthetic paths,and the in situ multiscale characterization techniques presented in this work provides a paradigm reference for shortening the research and development cycle of high-performance catalysts,conducive to facilitating the transition of photoelectrocatalytic CO_(2)RR technology from the laboratory routes to industrial application.展开更多
Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-...Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-doped carbon(Fe/SNC)via in situ incorporation of 2-aminothiazole molecules into zeolitic imidazolate framework-8(ZIF-8)through coordination between metal ions and organic ligands.Sulfur and nitrogen doping in carbon supports effectively modulates the electronic structure of the catalyst,increases the Brunauer-Emmett-Teller surface area,and exposes more Fe-N_(x)active centers.Fe-loaded,S and N co-doped carbon with Fe/S molar ratio of 1:10(Fe/SNC-10)exhibits a half-wave potential of 0.902 V vs.RHE.After 5000 cycles of cyclic voltammetry,its half-wave potential decreases by only 20 mV vs.RHE,indicating excellent stability.Due to sulfur s lower electronegativity,the electronic structure of the Fe-N_(x)active center is modulated.Additionally,the larger atomic radius of sulfur introduces defects into the carbon support.As a result,Fe/SNC-10 demonstrates superior ORR activity and stability in alkaline solution compared with Fe-loaded N-doped carbon(Fe/NC).Furthermore,the zinc-air battery assembled with the Fe/SNC-10 catalyst shows enhanced performance relative to those assembled with Fe/NC and Pt/C catalysts.This work offers a novel design strategy for advanced energy storage and conversion applications.展开更多
Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction...Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction(ORR)and chlorideinduced degradation over conventional catalysts.In this study,we proposed a universal synthetic strategy to construct heteroatom axially coordinated Fe–N_(4) single-atom seawater catalyst materials(Cl–Fe–N_(4) and S–Fe–N_(4)).X-ray absorption spectroscopy confirmed their five-coordinated square pyramidal structure.Systematic evaluation of catalytic activities revealed that compared with S–Fe–N_(4),Cl–Fe–N_(4) exhibits smaller electrochemical active surface area and specific surface area,yet demonstrates higher limiting current density(5.8 mA cm^(−2)).The assembled zinc-air batteries using Cl–Fe–N_(4) showed superior power density(187.7 mW cm^(−2) at 245.1 mA cm^(−2)),indicating that Cl axial coordination more effectively enhances the intrinsic ORR activity.Moreover,Cl–Fe–N_(4) demonstrates stronger Cl−poisoning resistance in seawater environments.Chronoamperometry tests and zinc-air battery cycling performance evaluations confirmed its enhanced stability.Density functional theory calculations revealed that the introduction of heteroatoms in the axial direction regulates the electron center of Fe single atom,leading to more active reaction intermediates and increased electron density of Fe single sites,thereby enhancing the reduction in adsorbed intermediates and hence the overall ORR catalytic activity.展开更多
Electrocatalytic reduction reactions play a crucial role in electrochemical energy conversion and storage technology,which are emerging technologies to ameliorate environmental problems.Spinel oxides are widely explor...Electrocatalytic reduction reactions play a crucial role in electrochemical energy conversion and storage technology,which are emerging technologies to ameliorate environmental problems.Spinel oxides are widely explored in electrocatalytic oxidation reactions but have a poor intrinsic ability to reduction reactions,making their electrocatalytic ability less effective.To improve this,defect engineering is a valuable method for regulating the electronic structure and coordination environment.Herein,this manuscript discusses the use of defect spinel oxides in electrocatalytic reduction reactions,including the different types of defects,construction methods,and characterization techniques.It also outlines the various applications of defect spinel oxides in different electrocatalytic reduction reactions.Finally,it goes over the challenges and future outlooks for defect spinels.This review aims to thoroughly explain how defect spinels work in electrocatalytic reduction reactions and serve as a helpful guide for creating effective electrocatalysts.展开更多
Noble metals, such as platinum, ruthenium and iridium‐group metals, are often used as oxygen reduction or evolution reaction （ORR/OER） electrocatalysts. To reduce the cost and provide an application of bifunctional...Noble metals, such as platinum, ruthenium and iridium‐group metals, are often used as oxygen reduction or evolution reaction （ORR/OER） electrocatalysts. To reduce the cost and provide an application of bifunctional catalysis, in this work, cobalt oxide supported on nitrogen and phospho‐rus co‐doped carbon （Co3O4/NPC） was fabricated and examined as a bifunctional electrocatalyst for OER and ORR. To prepare Co3O4/NPC, NPC was pyrolyzed from melamine and phytic acid support‐ed on carbon, followed by the solvothermal synthesis of Co3O4 on NPC. Linear sweep voltammetry was used to evaluate the activity for OER and ORR. For OER, Co3O4/NPC showed an onset potential of 0.54 V （versus the saturated calomel electrode） and a current density of 21.95 mA/cm2 at 0.80 V, which was better than both Co3O4/C and NPC. The high activity of Co3O4/NPC was attributed to a synergistic effect of the N, P co‐dopants and Co3O4. For ORR, Co3O4/NPC exhibited an activity close to commercial Pt/C in terms of the diffusion limited current density （–4.49 vs–4.76 mA/cm2 at–0.80 V）, and Co3O4 played the key role for the catalysis. Chronoamperometry （current versus time） was used to evaluate the stability, which showed that Co3O4/NPC maintained 46%current after the chronoamperometry test for OER and 95% current for ORR. Overall, Co3O4/NPC exhibited high activity and improved stability for both OER and ORR.展开更多
The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electro...The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electrolysers, fuel cells, and metal–air batteries emerge in response to the need for developing sustainable energy carriers, in which the oxygen evolution reaction and the oxygen reduction reaction play key roles. However, both reactions suffer from sluggish kinetics that restricts the reactivity. Therefore, it is vital to probe into the structure of the catalysts to exploit high-performance bifunctional oxygen electrocatalysts. Spinel-type catalysts are a class of materials with advantages of versatility, low toxicity, low expense, high abundance, flexible ion arrangement, and multivalence structure. In this review, we afford a basic overview of spinel-type materials and then introduce the relevant theoretical principles for electrocatalytic activity, following that we shed light on the structure–property relationship strategies for spinel-type catalysts including electronic structure, microstructure, phase and composition regulation,and coupling with electrically conductive supports. We elaborate the relationship between structure and property, in order to provide some insights into the design of spinel-type bifunctional oxygen electrocatalysts.展开更多
基金financial support from the National Natural Science Foundation of China(No.22072183)the Natural Science Foundation of Hunan Province,China(No.2022JJ30690)supported in part by the High Performance Computing Center of Central South University。
文摘Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency.
基金supported by the National Natural Science Foundation of China(21476087,21576101)the Innovation Project of Guangdong Department of Education(2014KTSCX016)+1 种基金the Science&Technology Research Project of Guangdong Province(2013B010405005,2014A010105041)the Fundamental Research Funds for the Central Universities~~
文摘Aniline,pyrrole and phenanthroline,which have different nitrogen compositions,are used as carbon precursors to synthesize nitrogen-doped ordered mesoporous carbons（NOMCs） by the nanocasting method.The effect of the precursor on the resultant NOMC is extensively investigated by nitrogen adsorption-desorption measurements,scanning electron microscopy,X-ray photoelectron spectroscopy（XPS）,cyclic voltammetry and rotating ring-disk electrode measurements.Salient findings are as follows.First,the precursor has a significant influence on the specific surface area and textural properties.The NOMC materials derived from pyrrole（C-PY-900：765 m^2/） and phenanthroline（C-Phen-900：746 m^2/） exhibit higher specific surface areas than the aniline analog（C-PA-900：569 m^2/）.Second,the XPS results indicate that the total nitrogen content（ca.3.1–3.3 at%） is similar for the three carbon sources,except for a slight difference in the nitrogen configuration.Furthermore,the content of the nitrogen-activated carbon atoms is found to closely depend on the precursor,which is the highest for the phenanthroline-derived carbon.Third,the electrochemical results reveal that the electrocatalytic activity follows in the order C-PA-900 C-PY-900 C-Phen-900,confirming that the nitrogen-activated carbon atoms are the active sites for the oxygen reduction reaction（ORR）.In summary,the precursor has considerable influence on the composition and textural properties of the NOMC materials,of which the ORR electrocatalytic activity can be enhanced through optimization of the NOMCs.
基金the National Natural Science Foundation of China(No.52072256)Shanxi Science and Technology Major Project(No.20201101016)+1 种基金Key R&D program of Shanxi Province(No.202102030201006)Research Project Supported by Shanxi Scholarship Council of China(HGKY2019031).
文摘Electrocatalytic oxygen reduction reaction(ORR)is one of the most important reactions in electrochemical energy technologies such as fuel cells and metal–O2/air batteries,etc.However,the essential catalysts to overcome its slow reaction kinetic always undergo a complex dynamic evolution in the actual catalytic process,and the concomitant intermediates and catalytic products also occur continuous conversion and reconstruction.This makes them difficult to be accurately captured,making the identification of ORR active sites and the elucidation of ORR mechanisms difficult.Thus,it is necessary to use extensive in-situ characterization techniques to proceed the real-time monitoring of the catalyst structure and the evolution state of intermediates and products during ORR.This work reviews the major advances in the use of various in-situ techniques to characterize the catalytic processes of various catalysts.Specifically,the catalyst structure evolutions revealed directly by in-situ techniques are systematically summarized,such as phase,valence,electronic transfer,coordination,and spin states varies.In-situ revelation of intermediate adsorption/desorption behavior,and the real-time monitoring of the product nucleation,growth,and reconstruction evolution are equally emphasized in the discussion.Other interference factors,as well as in-situ signal assignment with the aid of theoretical calculations,are also covered.Finally,some major challenges and prospects of in-situ techniques for future catalysts research in the ORR process are proposed.
基金financially supported by the Natural Science Foundation of Shanxi Province(No.201901D111277)the National Natural Science Foundation of China(No.21571119)+1 种基金the Graduate Science and Technology Innovation Project Foundation of Shanxi Normal University(No.2021DCXM71)the Program for New Century Excellent Talents in University(No.NCET-12-1035)。
文摘metal oxide electronic interactions in composite electrocatalysts have a considerable impact on their catalytic capability.In this study,we successfully synthesized an electrocatalytic material composed of MoO_(3)/C speciessupported Pd nanoparticles(Pd-MoO_(3)/C)using a convenient hydrothermal method,which exhibited excellent catalytic activities for both ethanol oxidation and oxygen reduction in KOH media.The specific activity of PdMoO_(3)/C toward ethanol oxidation with MoO_(3)loading(40wt%)was~2.6 times greater than that for the commercial Pd/C(10 wt%)with the same Pd content.In particular,the activity could effectively hold up to~60%of its maximum activity after 500-cycle tests,demonstrating improved cyclical stability.Notably,the fast electron transfer kinetics toward oxygen reduction for Pd-MoO_(3)/C(40%)were also comparable to those of commercial Pt/C(20 wt%)catalysts.These superior electrochemical features are primarily derived from the stronger electronic coupling between Pd and MoO_(3)through charge transfer,which can supply more active centers and improve the anti-poisoning ability.Meanwhile,the MoO_(3)species in the Pd-MoO_(3)/C composite may provide additional benefits in terms of electrical conductivity and dispersion.
文摘The electrochemical nitrogen reduction reaction(NRR)to directly produce NH3 from N_(2) and H_(2)O under ambient conditions has attracted significant attention due to its ecofriendliness.Nevertheless,the electrochemical NRR presents several practical challenges,including sluggish reaction and low selectivity.Here,bi-atom catalysts have been proposed to achieve excellent activity and high selectivity toward the electrochemical NRR by Ma and his co-workers.It could accelerate the kinetics of N_(2)-to-NH_(3) electrochemical conversion and possess better electrochemical NRR selectivity.This work sheds light on the introduction of bi-atom catalysts to enhance the performance of the electrochemical NRR.
文摘Studies have extensively addressed the development of electrocatalytic technologies for energy storage and conversion,fuel production,and environmental protection.Electrode processes such as different oxidation and reduction reactions play a vital and significant role in these technologies.In this regard,efficient,inexpensive,and stable electrocatalysts capable can significantly promote electrochemical reactions.Unique features of metal–organic frameworks(MOFs)such as their high porosity,tunable structure,size,and pore shape,high surface area,and redox properties have introduced them as an ideal electrocatalyst candidate.This review is thus aimed at elucidating the role of MOF-based materials(pristine,derivatives and composites)as efficient electrocatalysts in energy and sensing-related oxidation and reduction reactions such as oxygen reduction reaction(ORR),hydrogen oxidation reaction(HOR),carbon dioxide reduction reaction(CO_(2)RR),urea oxidation reaction(UOR),alcohol oxidation reaction(AOR),nitrogen reduction reaction(NRR),and glucose oxidation reaction(GOR)in advanced energy and sensing devices.Also,the structure–property relationship of the electrocatalyst was elaborated for each electrocatalytic reaction.Finally,perspectives on the potential research topics for practical use of MOF-based electrocatalysts are addressed.The present review can improve the interest in MOF-based electrocatalysts to study different oxidation and reduction reactions in energy and sensing systems.
文摘The pyrolysis under inert atmosphere has been widely used for the synthesis of metal containing heteroatoms doped carbon materials, versatile catalysts for various reactions. However, it is difficult to prevent metal nanoparticles aggregation during pyrolysis process. Herein, we reported the efficient synthesis of nitrogen doped carbon hollow nanospheres with cobalt nanoparticles （Co NP, ca. 10nm in size） distributed uniformly in the shell via pyrolysis of yolk-shell structured Zn-Co-ZIFs@polydopamine （PDA）. PDA acted as both protection layer and carbon source, which successfully prevented the aggregation of cobalt nanoparticles during high-temperature pyrolysis process. The Co NP and N containing carbon （Co NP/NC） hollow nanospheres were active for both oxygen evolution reaction （OER） and oxygen reduction reaction （ORR）, affording overpotential of 430 mV at 10 mA/cm2 for OER in 1 M KOH and comparable half-wave potential to that of Pt/C （0.80V vs RHE） for ORR in 0.1 M KOH. The superior performance of carbon hollow nanospheres for both OER and ORR was mainly attributed to its small metal nanoparticles, N-doping and hollow nanostructure. The protection and confinement effect that originated from PDA coating strategy could be extended to the synthesis of other hollow structured carbon materials, especially the ones with small metal nanoparticles.
文摘To replace precious metal oxygen reduction reaction(ORR)electrocatalysts,many transition metals and N-doped car-bon composites have been proposed in the last decade resulting in their rapid development as promising non-precious metal catalysts.We used Ketjenblack carbon as the precursor and mixed it with a polymeric ionic liquid(PIL)of[Hvim]NO_(3) and Fe(NO_(3))_(3),which was thermally calcined at 900℃ to produce a porous FeO_(x),N co-doped carbon material denoted FeO_(x)-N/C.Because the PIL of[Hvim]NO_(3) strongly combines with and disperses Fe^(3+)ions,and NO_(3)−is thermally pyrolyzed to form the porous structure,the FeO_(x)-N/C catalyst has a high electrocatalytic activity for the ORR in both 0.1 mol L^(−1) KOH and 0.5 mol L^(−1) H_(2)SO_(4) electrolytes.It was used as the catalyst to assemble a zinc-air battery,which had a peak power density of 185 mW·cm^(−2).Its superior electrocatalytic activity,wide pH range,and easy preparation make FeO_(x)-N/C a promising electrocatalyst for fuel cells and metal-air batteries.
文摘Electrocatalytic reduction reactions,powered by clean energy sources such as solar energy and wind,offer a sustainable method for converting inexpensive feedstocks(e.g.,CO_(2),N_(2)/NO_(x),organics,and O_(2))into high-value-added chemicals or fuels.The design and modification of electrocatalysts have been widely implemented to improve their performance in these reactions.However,bottle-necks are encountered,making it challenging to further improve performance through catalyst development alone.Recently,cations in the electrolyte have emerged as critical factors for tuning both the activity and product selectivity of reduction reactions.This review summarizes recent advances in understanding the role of cation effects in electrocatalytic reduction reactions.First,we introduce the mechanisms underlying cation effects.We then provide a comprehensive overview of their application in electroreduction reactions.Characterization techniques and theoretical calcula-tion methods for studying cation effects are also discussed.Finally,we address remaining challeng-es and future perspectives in this field.We hope that this review offers fundamental insights and design guidance for utilizing cation effects,thereby advancing their development.
基金This work was supported by the National Natural Science Foundation of China(Nos.91963113,51701139,and U1601216)。
文摘Oxygen evolution and oxygen reduction are considered as essential processes in the energy conversion devices.The progress of cost-effective bifunctional catalysts has become a critical issue to be solved.Here,we report that Co(OH)_(2)@N-doped carbon(NC)was facilely synthesized through the impregnation strategy of metal-organic frameworks derived carbon and cobalt ions.N-doped carbon with porous structure and cobalt hydroxide nanosheets play a synergistic effect role,representing excellent catalytic performance toward oxygen evolution and reduction reactions.The obtained Co(OH)_(2)@NC exhibits remarkable activity in terms of a lower overpotential of 330 mV@10 mA cm^(-2) for OER and a more positive half-wave potential(E_(1/2)=0.84 V)for ORR in alkaline medium,outperforming IrO_(2) and Pt/C.Due to its superior bifunctional catalytic performance,Co(OH)_(2)@NC catalyst is applied into a promising air electrode of Zn-air battery.This presented strategy of impregnation synthesis in this work provides a new design direction for practical electrochemical energy devices.
文摘The rotating disk electrode technique is commonly used for screening and characterizing the performance of electrocatalysts for the oxygen reduction reaction(ORR).However,a reliable performance comparison of different electrocatalysts from different labs remains a challenge because of the inconsistency in the measurement of commercial Pt/C.Commercial Pt/C has been adopted extensively as a reference for evaluating the ORR performance of a new electrocatalyst.However,the reported ORR performances of commercial Pt/C from different labs could be significantly different because of multiple factors.Herein,we conducted a meta‐analysis of the ORR performance of commercial Pt/C via data mining of the literature.This revealed the optimal testing conditions for the most repeatable ORR performance,with commercial Pt/C in both acid and alkaline electrolytes;the optimal Pt loading was 20μg/cm^(2) on a 4 mm glassy carbon working electrode.The value of 0.84±0.03 V was suggested as the“Golden reference”of the commercial Pt/C(with Pt 20 wt%)ORR half‐wave potential for the performance evaluation of other ORR catalysts in both acid and alkaline electrolytes.The conclusion obtained through the meta‐analysis was confirmed by experiments.This study provides general guidance for a reliable measurement of the ORR performance of commercial Pt/C as a reference.
基金supported by the National Natural Science Foundation of China(No.21905175).
文摘Hydrogen evolution reaction(HER)and oxygen evolution/reduction reaction(OER/ORR)relying on high-performance and low-cost single-atom catalysts(SACs)driven by renewable energy sources offer a sustainable route to carbon-neutral chemicals and fuels.Herein,first-principles calculations were performed to investigate the catalytic HER/OER/ORR activity of a novel graphitic carbon nitride monolayer(g-C_(7)N_(3))supported single transition metal(TM@g-C_(7)N_(3)).High stability as well as positively charged active site(TM-site)and desirable electrical conductivity lay the foundation for TM@g-C_(7)N_(3)acting as efficient HER/OER/ORR electrocatalysts.We screened out the non-noble-metal Rh@g-C_(7)N_(3)SAC exhibiting great potential as the trifunctional electrocatalysts for water splitting(η^(HER)=0.06 V andηOER=0.46 V)and a metal-air battery(η^(ORR)=0.28 V)on both kinetic and thermodynamic scales,whereas the Ni@g-C_(7)N_(3)can be served as a bifunctional OER/ORR catalyst with a low overpotential of 0.33 V/0.31 V,for both of which the high thermodynamic stability and oxidation barrier guarantee their outstanding performances at ambient conditions.The mechanism analysis indicates the filling of d-orbital electrons of TM-atom can play an important role in determining the value of an energy descriptor(ΔGOH*),and the suitableΔGOH*values make for the TM@g-C_(7)N_(3)candidates to possess favorable OER/ORR overpotential.Particularly,the Rh-d orbital of Rh@g-C_(7)N_(3)is evidently hybridized with the OH*-p orbital,resulting in the lone electrons initially distributed in the antibonding orbital pairing up and occupying the downward bonding orbital,ensuring OH*can be adsorbed on Rh@g-C_(7)N_(3)appropriately.Moreover,multiple-level descriptors including d-band center,COHP,Nd,andφare used to reveal the origin of the electrocatalytic activity.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.22305071,52472200,52271176,and52072114)the 111 Project(Grant No.D17007)+3 种基金Henan Center for Outstanding Overseas Scientists(Grant No.GZS2022017)the China Postdoctoral Science Foundation(Grant No.2022M721049)the Henan Province Key Research and Development Project(Grant No.231111520500)the Natural Science Foundation of Henan Province(Grant No.252300421556)。
文摘Development of high-efficiency bifunctional oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalysts is vital for the widespread application of zinc-air batteries(ZABs).However,it still remains a great challenge to avoid the inhomogeneous distribution and aggregation of metal single-atomic active centers in the construction of bifunctional electrocatalysts with atomically dispersed multimetallic sites because of the common calcination method.Herein,we report a novel catalyst with phthalocyanine-assembled Fe-Co-Ni single-atomic triple sites dispersed on sulfur-doped graphene using a simple ultrasonic procedure without calcination,and X-ray absorption fine structure(XAFS),aberration-corrected scanning transmission electron microscopy(AC-STEM),and other detailed characterizations are performed to demonstrate the successful synthesis.The novel catalyst shows extraordinary bifunctional ORR/OER activities with a fairly low potential difference(ΔE=0.621 V)between the OER overpotential(Ej10=315 mV at 10 m A cm^(-2))and the ORR half-wave potential(Ehalf-wave=0.924 V).Moreover,the above catalyst shows excellent ZAB performance,with an outstanding specific capacity(786 mAh g^(-1)),noteworthy maximum power density(139 mW cm^(-2)),and extraordinary rechargeability(discharged and charged at 5 mA cm^(-2) for more than 1000 h).Theoretical calculations reveal the vital importance of the preferable synergetic coupling effect between adjacent active sites in the Fe-Co-Ni trimetallic single-atomic sites during the ORR/OER processes.This study provides a new avenue for the investigation of bifunctional electrocatalysts with atomically dispersed trimetallic sites,which is intended for enhancing the ORR/OER performance in ZABs.
基金supported by the National Natural Science Foundation of China(Grant No.22302042)the Pilot Group Program of the Research Fund for International Senior Scientists(Grant No.22250710676).
文摘High entropy alloys(HEAs)have gained significant attention in electrocatalysis research due to their distinctive multi-element composition,intricate electronic structure,and superior properties.By harnessing multi-component synergy,precise electron regulation,and the high-entropy effect,HEA electrocatalysts exhibit remarkable catalytic activity,selectivity,and stability.These materials demonstrate outstanding catalytic performance in a variety of electrocatalytic small molecule reduction reactions,including oxygen reduction(ORR),hydrogen evolution(HER),and CO_(2)reduction(CO_(2)RR),making them promising candidates for clean energy conversion and storage applications,including fuel cells,metal-air batteries,water electrolysis,and CO_(2)conversion technologies.This review highlights recent advancements in HEA electrocatalyst research,focusing on their synthesis,characterization,and applications in electrocatalytic small molecule reduction reactions.It also explores the underlying mechanisms of the high-entropy effect,multi-component synergy,and structural design.Finally,it discusses key challenges that remain in the application of HEAs for electrocatalytic small molecule reduction and outlines potential directions for future development in this field.
基金supports from the National Natural Science Foundation of China(Grant Nos.12305372 and 22376217)the National Key Research&Development Program of China(Grant Nos.2022YFA1603802 and 2022YFB3504100)+1 种基金the projects of the key laboratory of advanced energy materials chemistry,ministry of education(Nankai University)key laboratory of Jiangxi Province for persistent pollutants prevention control and resource reuse(2023SSY02061)are gratefully acknowledged.
文摘Using photoelectrocatalytic CO_(2) reduction reaction(CO_(2)RR)to produce valuable fuels is a fascinating way to alleviate environmental issues and energy crises.Bismuth-based(Bi-based)catalysts have attracted widespread attention for CO_(2)RR due to their high catalytic activity,selectivity,excellent stability,and low cost.However,they still need to be further improved to meet the needs of industrial applications.This review article comprehensively summarizes the recent advances in regulation strategies of Bi-based catalysts and can be divided into six categories:(1)defect engineering,(2)atomic doping engineering,(3)organic framework engineering,(4)inorganic heterojunction engineering,(5)crystal face engineering,and(6)alloying and polarization engineering.Meanwhile,the corresponding catalytic mechanisms of each regulation strategy will also be discussed in detail,aiming to enable researchers to understand the structure-property relationship of the improved Bibased catalysts fundamentally.Finally,the challenges and future opportunities of the Bi-based catalysts in the photoelectrocatalytic CO_(2)RR application field will also be featured from the perspectives of the(1)combination or synergy of multiple regulatory strategies,(2)revealing formation mechanism and realizing controllable synthesis,and(3)in situ multiscale investigation of activation pathways and uncovering the catalytic mechanisms.On the one hand,through the comparative analysis and mechanism explanation of the six major regulatory strategies,a multidimensional knowledge framework of the structure-activity relationship of Bi-based catalysts can be constructed for researchers,which not only deepens the atomic-level understanding of catalytic active sites,charge transport paths,and the adsorption behavior of intermediate products,but also provides theoretical guiding principles for the controllable design of new catalysts;on the other hand,the promising collaborative regulation strategies,controllable synthetic paths,and the in situ multiscale characterization techniques presented in this work provides a paradigm reference for shortening the research and development cycle of high-performance catalysts,conducive to facilitating the transition of photoelectrocatalytic CO_(2)RR technology from the laboratory routes to industrial application.
基金financial support of the National Natural Science Foundation of China(No.52472271)the National Key Research and Development Program of China(No.2023YFE0115800)。
文摘Heteroatom-doped carbon is considered a promising alternative to commercial Pt/C as an efficient catalyst for the oxygen reduction reaction(ORR).This study presents the synthesis of iron-loaded,sulfur and nitrogen co-doped carbon(Fe/SNC)via in situ incorporation of 2-aminothiazole molecules into zeolitic imidazolate framework-8(ZIF-8)through coordination between metal ions and organic ligands.Sulfur and nitrogen doping in carbon supports effectively modulates the electronic structure of the catalyst,increases the Brunauer-Emmett-Teller surface area,and exposes more Fe-N_(x)active centers.Fe-loaded,S and N co-doped carbon with Fe/S molar ratio of 1:10(Fe/SNC-10)exhibits a half-wave potential of 0.902 V vs.RHE.After 5000 cycles of cyclic voltammetry,its half-wave potential decreases by only 20 mV vs.RHE,indicating excellent stability.Due to sulfur s lower electronegativity,the electronic structure of the Fe-N_(x)active center is modulated.Additionally,the larger atomic radius of sulfur introduces defects into the carbon support.As a result,Fe/SNC-10 demonstrates superior ORR activity and stability in alkaline solution compared with Fe-loaded N-doped carbon(Fe/NC).Furthermore,the zinc-air battery assembled with the Fe/SNC-10 catalyst shows enhanced performance relative to those assembled with Fe/NC and Pt/C catalysts.This work offers a novel design strategy for advanced energy storage and conversion applications.
基金funded by the Innovative Research Group Project of the National Natural Science Foundation of China(52121004)the Research Development Fund(No.RDF-21-02-060)by Xi’an Jiaotong-Liverpool University+1 种基金support received from the Suzhou Industrial Park High Quality Innovation Platform of Functional Molecular Materials and Devices(YZCXPT2023105)the XJTLU Advanced Materials Research Center(AMRC).
文摘Seawater zinc-air batteries are promising energy storage devices due to their high energy density and utilization of seawater electrolytes.However,their efficiency is hindered by the sluggish oxygen reduction reaction(ORR)and chlorideinduced degradation over conventional catalysts.In this study,we proposed a universal synthetic strategy to construct heteroatom axially coordinated Fe–N_(4) single-atom seawater catalyst materials(Cl–Fe–N_(4) and S–Fe–N_(4)).X-ray absorption spectroscopy confirmed their five-coordinated square pyramidal structure.Systematic evaluation of catalytic activities revealed that compared with S–Fe–N_(4),Cl–Fe–N_(4) exhibits smaller electrochemical active surface area and specific surface area,yet demonstrates higher limiting current density(5.8 mA cm^(−2)).The assembled zinc-air batteries using Cl–Fe–N_(4) showed superior power density(187.7 mW cm^(−2) at 245.1 mA cm^(−2)),indicating that Cl axial coordination more effectively enhances the intrinsic ORR activity.Moreover,Cl–Fe–N_(4) demonstrates stronger Cl−poisoning resistance in seawater environments.Chronoamperometry tests and zinc-air battery cycling performance evaluations confirmed its enhanced stability.Density functional theory calculations revealed that the introduction of heteroatoms in the axial direction regulates the electron center of Fe single atom,leading to more active reaction intermediates and increased electron density of Fe single sites,thereby enhancing the reduction in adsorbed intermediates and hence the overall ORR catalytic activity.
基金supported by National Natural Science Foundation of China(Nos.22272047,21905088,22102155)the China Postdoctoral Science Foundation(Nos.2021M692909,2022T150587)the Provincial Natural Science Foundation of Hunan(No.2022JJ10006).
文摘Electrocatalytic reduction reactions play a crucial role in electrochemical energy conversion and storage technology,which are emerging technologies to ameliorate environmental problems.Spinel oxides are widely explored in electrocatalytic oxidation reactions but have a poor intrinsic ability to reduction reactions,making their electrocatalytic ability less effective.To improve this,defect engineering is a valuable method for regulating the electronic structure and coordination environment.Herein,this manuscript discusses the use of defect spinel oxides in electrocatalytic reduction reactions,including the different types of defects,construction methods,and characterization techniques.It also outlines the various applications of defect spinel oxides in different electrocatalytic reduction reactions.Finally,it goes over the challenges and future outlooks for defect spinels.This review aims to thoroughly explain how defect spinels work in electrocatalytic reduction reactions and serve as a helpful guide for creating effective electrocatalysts.
基金supported by the National Natural Science Foundation of China (21375016,20475022 and 21505019)~~
文摘Noble metals, such as platinum, ruthenium and iridium‐group metals, are often used as oxygen reduction or evolution reaction （ORR/OER） electrocatalysts. To reduce the cost and provide an application of bifunctional catalysis, in this work, cobalt oxide supported on nitrogen and phospho‐rus co‐doped carbon （Co3O4/NPC） was fabricated and examined as a bifunctional electrocatalyst for OER and ORR. To prepare Co3O4/NPC, NPC was pyrolyzed from melamine and phytic acid support‐ed on carbon, followed by the solvothermal synthesis of Co3O4 on NPC. Linear sweep voltammetry was used to evaluate the activity for OER and ORR. For OER, Co3O4/NPC showed an onset potential of 0.54 V （versus the saturated calomel electrode） and a current density of 21.95 mA/cm2 at 0.80 V, which was better than both Co3O4/C and NPC. The high activity of Co3O4/NPC was attributed to a synergistic effect of the N, P co‐dopants and Co3O4. For ORR, Co3O4/NPC exhibited an activity close to commercial Pt/C in terms of the diffusion limited current density （–4.49 vs–4.76 mA/cm2 at–0.80 V）, and Co3O4 played the key role for the catalysis. Chronoamperometry （current versus time） was used to evaluate the stability, which showed that Co3O4/NPC maintained 46%current after the chronoamperometry test for OER and 95% current for ORR. Overall, Co3O4/NPC exhibited high activity and improved stability for both OER and ORR.
基金supported by the Natural Scientific Foundation of China (21825501)National Key Research and Development Program (2016YFA0202500 and 2016YFA0200102)+1 种基金Australian Research Council (DP160103107, FT170100224)Tsinghua University Initiative Scientific Research Program。
文摘The demand for efficient and environmentally-benign electrocatalysts that help availably harness the renewable energy resources is growing rapidly. In recent years, increasing insights into the design of water electrolysers, fuel cells, and metal–air batteries emerge in response to the need for developing sustainable energy carriers, in which the oxygen evolution reaction and the oxygen reduction reaction play key roles. However, both reactions suffer from sluggish kinetics that restricts the reactivity. Therefore, it is vital to probe into the structure of the catalysts to exploit high-performance bifunctional oxygen electrocatalysts. Spinel-type catalysts are a class of materials with advantages of versatility, low toxicity, low expense, high abundance, flexible ion arrangement, and multivalence structure. In this review, we afford a basic overview of spinel-type materials and then introduce the relevant theoretical principles for electrocatalytic activity, following that we shed light on the structure–property relationship strategies for spinel-type catalysts including electronic structure, microstructure, phase and composition regulation,and coupling with electrically conductive supports. We elaborate the relationship between structure and property, in order to provide some insights into the design of spinel-type bifunctional oxygen electrocatalysts.
