The design of efficient and robust non-precious metal electrocatalysts towards oxygen evolution reaction(OER)is of great value for developing green energy technologies.The in-situ formed high-valence(oxy)hydroxides sp...The design of efficient and robust non-precious metal electrocatalysts towards oxygen evolution reaction(OER)is of great value for developing green energy technologies.The in-situ formed high-valence(oxy)hydroxides species during the reconstruction process of pre-catalysts are recognized as the real contributing sites for OER.However,pre-catalysts generally undergo a slow and inadequate self-reconstruction.Herein,we reported a PO^(3-)_(4)optimized CoFe-based OER catalysts with amorphous structure,which enables a fast and deep reconstruction during the OER process.The amorphous structure induced by ligands PO^(3-)_(4)is prone to evolution and further form active species for OER.The electron interaction between metal sites can be modulated by electron-rich PO^(3-)_(4),which promotes generation of high active CoOOH.Simultaneously,the etching of PO^(3-)_(4)from the pre-catalysts during the catalytic process is in favor of accelerating the self-reconstruction.As a result,as-prepared precatalyst can generate high active CoOOH at a low potential of 1.4 V and achieve an in-depth reconstructed nanosheet structure with abundant OER active sites.Our work provides a promising design of pre-catalysts for realizing efficient catalysis of water oxidation.展开更多
In this work,we fabricated an efficient pre-catalyst based on(Ni,Co)S2solid solution with hierarchical architecture and high porosity to boost urea oxidation reaction and electrocatalytic oxidation of organic small mo...In this work,we fabricated an efficient pre-catalyst based on(Ni,Co)S2solid solution with hierarchical architecture and high porosity to boost urea oxidation reaction and electrocatalytic oxidation of organic small molecules.The interaction between Ni and Co can optimize the electronic structure,resulting in the improved conductivity and accelerated charge transfer rate.The 2D/3D architecture can enrich more active species and endow the mass and electron transport to facilitate the surface oxidation and the following catalytic process.Post-structure and catalytic characterizations confirm the surface oxidation of(Ni,Co)S_(2)during the stability test,and the in-situ formed Co(Ni)based(oxy)hydroxides exhibit superior catalytic activity and facilitated charge transfer ability.As a result,the optimal(Ni,Co)S_(2)solid solution pre-catalyst displays facilitated catalytic behavior and good stability for multifunctional electrocatalytic oxidation,in which a high conversion of benzyl alcohol(97.50%),a good selectivity to benzoic acid(93.78%)and a satisfied faraday efficiency(91.86%)can be achieved.展开更多
Fabrication of single-crystalline metal-organic framework(MOF)hollow nanostructures with two-dimensional(2D)morphologies is a challenging task.Herein,twin-like MOF nanobricks,a quasi-hollow 2D architecture,with multi-...Fabrication of single-crystalline metal-organic framework(MOF)hollow nanostructures with two-dimensional(2D)morphologies is a challenging task.Herein,twin-like MOF nanobricks,a quasi-hollow 2D architecture,with multi-metal nodes and replaceable organic ligands,are uniformly and firmly grown on conductive Ni foam through a generic one-pot approach.The formation process of twin-like MOF nanobricks mainly includes selective epitaxial growth of Fe-rich MOF layer and simultaneously dissolution of the pre-formed Ni-rich metal-organic frameworks(MOFs),all of which can be ascribed to a special self-templated mechanism.The fantastic structural merits of twin-like MOF nanobrick arrays,featuring highly exposed active sites,remarkable electrical conductivity,and hierarchical porosities,enable this material for efficient electrocatalysis.Using bimetallic NiFe-MOFs grown on Ni foam as an example,the resultant twin-like nanobrick arrays can be directly utilized as three-dimensional(3D)integrated electrode for high-performance water oxidation in 1 M KOH with a low overpotential,fast reaction kinetics(28.5 mV·dec^(-1)),and superb stability.Interestingly,the unstable NiFe-MOFs were served as an oxygen evolution reaction(OER)pre-catalyst and the single-crystalline NiFe-MOF precursor can be in-situ topochemically regulated into porous and lowcrystalline NiFeOx nanosheets during the OER process.This work extends the hollowing strategy to fabricate hollow MOFs with 2D architectures and highlights their direct utilization for advanced electrocatalysis.展开更多
Amorphous transition metal compounds(a-TMC)become one of the most promising pre-catalysts toward oxygen evolution reaction(OER)due to their high-entropy nature and flexible self-reconstruction to highly active derivat...Amorphous transition metal compounds(a-TMC)become one of the most promising pre-catalysts toward oxygen evolution reaction(OER)due to their high-entropy nature and flexible self-reconstruction to highly active derivatives.However,the loosen bonds inside the amorphous structure make it an electronic insulator with unstable structure.Here,monodispersed Ni^(2+)-phytate nanospheres implanted by Fe^(3+)ions(NS_(FeNiPA))were firstly prepared and subsequently transferred into homogeneous high-entropy type Fe-Ni-P-O-C amorphous nanospheres(CNS_(FeNiPO)).It is shown that the CNS_(FeNiPO) presents robust structure and remarkable Fe ions migration during potential-driven activation process,which benefits efficient surface reconstruction and spherical morphology preservation.The CNS_(FeNiPO) with low mass loading of 0.1mg/cm^(2)could deliver small overpotential of 270mV at 10mAcm^(−2)and almost 100%retention of the initial current density after 10h test.The improved electrocatalytic activity is attributed to the boosted electron transfer from Ni sites to O-containing intermediates by introduction of Fe and P atoms.Moreover,rechargeable Zn-air battery with CNS_(FeNiPO)+Pt/C could achieve lower charge potential platform and better cycling performance than that with commercial RuO_(2)+Pt/C.This work provides new insights into the design and understanding of high-entropy amorphous pre-catalysts toward OER.展开更多
The development of inexpensive and efficient electrocatalysts is key to commercializing energy-related electrocatalytic techniques such as water electrolyzers and metal-air batteries.In particular,novel oxygen evoluti...The development of inexpensive and efficient electrocatalysts is key to commercializing energy-related electrocatalytic techniques such as water electrolyzers and metal-air batteries.In particular,novel oxygen evolution reaction(OER)pre-catalysts,such as transition metal chalcogenides(TMCs)and phosphides(TMPs),have evolved in recent years from traditional stable OER electrocatalysts,which show superior OER electrocatalytic performance compared with transition metal oxides(TMOs)or(oxy)hydroxides(TMOHs).In this feature article,we summarize recent advances in the development of TMCand TMP-based OER electrocatalysts,as well as approaches to improve the OER performance in terms of morphology,structure,composition,surface engineering,lattice-strained and in-situ transformation in the electrolysis process.In particular,the electrochemical stability of TMCs and TMPs in alkaline electrolytes and the evolution of morphology,structure and composition under OER conditions are discussed.In the last section,we discuss the challenges that need to be addressed in this specific area of research and the implications for further research.展开更多
For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial ...For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but challenging.In this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction conditions.Upon activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches.The catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride counterparts.The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break.Particularly,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).展开更多
The development of sustainable hydrogen production technologies is critical to addressing the global energy crisis and environmental challenges.Among water electrolysis systems,anion-exchange membrane water electrolyz...The development of sustainable hydrogen production technologies is critical to addressing the global energy crisis and environmental challenges.Among water electrolysis systems,anion-exchange membrane water electrolyzers(AEMWEs)have gained attention for their ability to combine cost-effectiveness with high efficiency.However,AEMWEs face challenges such as sluggish oxygen evolution reaction(OER)catalysts with low conductivity and density of active sites,especially with the feed stock of pure water.In this study,a tri-metal Prussian blue analogue(PBA)was synthesized at room temperature and employed as an efficient OER pre-catalyst.Electrochemical activation of this as-prepared material in the alkaline solution generates highly active and conductive crystalline-amorphous metal(oxy)hydroxides as the true catalytic sites,which exhibited exceptional OER performance with the overpotential of 251 mV at 10 mA·cm^(-2) and stable operation for 500 h in the alkaline solution.When applied as anode in AEMWEs,it delivered 1 A·cm^(-2) at 1.72 and 2.20 V with the feedstock of alkaline solution(1 M KOH)and pure water,respectively,demonstrating its large application prospect in AEMWE.展开更多
The rational design of high-performance bifunctional electrocatalysts for overall water splitting(OWS)is the key to popularize hydrogen production technology.The active metal oxyhydroxide(MOOH)formed after surface sel...The rational design of high-performance bifunctional electrocatalysts for overall water splitting(OWS)is the key to popularize hydrogen production technology.The active metal oxyhydroxide(MOOH)formed after surface self-reconfiguration of transition metal sulfide(TMS)electrocatalyst is often regarded as the"actual catalyst"in oxygen evolution reaction(OER).Herein,an Fe doped Co S2/Mo S2hollow TMS polyhedron(Fe-Co S2/Mo S2)with rich Mott-Schottky heterojunction is reported and directly utilized as an OWS electrocatalyst.The spontaneous built-in electric field(BEF)at the heterogeneous interface regulates the electronic structure and D-band center of the catalyst.More importantly,the“TMS-MOOH”core-shell structure obtained in the KOH electrolyte shows enhanced OER properties.And the introduction of Fe ions activates the inert basal plane of Mo S2,which greatly steps up the performance of HER.Hence,the preferable Fe-CoS_(2)/MoS_(2)–400 presents superior OER activity(η_(10)=178 m V,η_(100)=375 m V),HER activity(η_(10)=92 m V)and ultra-high stability for 50 h.This work has deeply explored the catalytic mechanism of TMS and provided a new idea for the construction of efficient bifunctional catalysts.展开更多
Developing high-efficiency and low-cost oxygen evolution reaction(OER)catalysts is crucial to advance the water splitting technology for sustainable hydrogen production.Here,a FeCoNi coordinated benzene-1,3,5-tricarbo...Developing high-efficiency and low-cost oxygen evolution reaction(OER)catalysts is crucial to advance the water splitting technology for sustainable hydrogen production.Here,a FeCoNi coordinated benzene-1,3,5-tricarboxylic acid(FeCoNiBTC)metal-organic framework(MOF)was synthesized by one-step solvothermal method for OER.A rapid in-situ chemical and electrochemical transformation was observed on the surface of the FeCoNiBTC MOF during OER process.The formed catalytic active FeCoNiOx(OH)y species retained the unique structure feature of initial FeCoNiBTC,moreover,it possessed multiple transition metal active nodes that cooperate with each other to adjust the electronic structure.Owing to the above structure advantages,the in-situ transformed FeCoNiOx(OH)y showed excellent OER catalytic activity with a small overpotential of 230 mV to achieve the 100 mA·cm^(−2),a low Tafel slope of 50.2 mV·dec^(−1),and superior stability of almost 80 h in alkaline aqueous solution.This work systematically studies the structure-performance relations of the multi-metal MOF-based materials in OER process,and it would enrich the exploration of highly efficient OER electrocatalysts.展开更多
A new two-stage catalytic system was developed to overcome the problems of low yield of hydrogenrich gas and serious carbon deposition on the catalyst during biomass pyrolysis catalysis.The operating temperature,catal...A new two-stage catalytic system was developed to overcome the problems of low yield of hydrogenrich gas and serious carbon deposition on the catalyst during biomass pyrolysis catalysis.The operating temperature,catalyst type and catalyst addition ratio were compared,and the optimum hydrogen production conditions were obtained(with yield reaching 52.21 wt%and the hydrogen yield reaching 29.15 vol%).The catalysts were modified by metals,including Ni,Ni-Co,Ni-Fe,Ni-Mo and Ni-Ce.Ni-Ce/Al_(2)O_(3)exhibited the highest tar-cracking efficiency during one-stage catalysis,attributed to the redox cycle between Ce^(3+)/Ce^(4+).In order to further improve the catalytic performance,the biochar pre-catalytic layer with rich porous structure and surface functional groups was introduced.Macromolecular volatiles were selectively adsorbed by the pre-catalyst and promoted in chain reactions.Macromolecular volatiles were selectively adsorbed by the pre-catalyst,in which the tar reforming reaction was promoted,resulting in an increase in hydrogen production to 29.76-48.87 vol%in two-stage catalysis.In addition,Biochar pre-catalyst promoted free radical recombination by enhancing the formation of H_(2)and H·and reducing the binding of polycyclic aromatic hydrocarbons,which effectively inhibited carbon deposition.This study provides theoretical insights and proposes a novel stepwise catalytic strategy for efficient hydrogen production from biomass,highlighting its potential for practical energy conversion applications.展开更多
In this study,post-consumer low-density polyethylene packaging waste was converted via plasma-assisted and conventional thermal pyrolysis,respectively.A perovskite-type La_(0.6)Ca0.4Co_(0.2)Fe_(0.8)O_(3−δ)pre-catalys...In this study,post-consumer low-density polyethylene packaging waste was converted via plasma-assisted and conventional thermal pyrolysis,respectively.A perovskite-type La_(0.6)Ca0.4Co_(0.2)Fe_(0.8)O_(3−δ)pre-catalyst was employed to simultaneously generate hydrogen and carbon nanomaterials.The plasma-thermal catalytic process demonstrated superior conversion efficiency for both gaseous and solid products compared to the two-stage thermal catalytic approach.To evaluate the potential of the synthesized carbon nanotube composites for low-grade energy storage applications,the metal oxide-carbon composites obtained from both synthesis methods were employed as a host for sulfur cathodes in lithium-sulfur batteries.Electrochemical analysis demonstrated comparable cycling stability between the two approaches,with initial discharge capacities of 296 and 291 mAh g^(−1),which stabilized at 125 and 112 mAh g^(−1)after 50 cycles at a 0.05 C(1C=1675 mAh g^(−1))rate for the plasma-thermal and thermal catalytic processes,respectively.These results highlight the feasibility of directly incorporating the derived carbon nanotube composites into energy storage technologies,offering a potentially sustainable route for large-scale plastic waste valorization and advanced material development.展开更多
基金financially supported by the National Natural Science Foundation of China (Grants Nos.51772338,51972349,91963210 and U1801255).
文摘The design of efficient and robust non-precious metal electrocatalysts towards oxygen evolution reaction(OER)is of great value for developing green energy technologies.The in-situ formed high-valence(oxy)hydroxides species during the reconstruction process of pre-catalysts are recognized as the real contributing sites for OER.However,pre-catalysts generally undergo a slow and inadequate self-reconstruction.Herein,we reported a PO^(3-)_(4)optimized CoFe-based OER catalysts with amorphous structure,which enables a fast and deep reconstruction during the OER process.The amorphous structure induced by ligands PO^(3-)_(4)is prone to evolution and further form active species for OER.The electron interaction between metal sites can be modulated by electron-rich PO^(3-)_(4),which promotes generation of high active CoOOH.Simultaneously,the etching of PO^(3-)_(4)from the pre-catalysts during the catalytic process is in favor of accelerating the self-reconstruction.As a result,as-prepared precatalyst can generate high active CoOOH at a low potential of 1.4 V and achieve an in-depth reconstructed nanosheet structure with abundant OER active sites.Our work provides a promising design of pre-catalysts for realizing efficient catalysis of water oxidation.
基金supported by National Natural Science Foundation of China(Nos.21927811,51602182,21808129)the Natural Science Foundation of Shandong Province,China(No.ZR2021ME032)。
文摘In this work,we fabricated an efficient pre-catalyst based on(Ni,Co)S2solid solution with hierarchical architecture and high porosity to boost urea oxidation reaction and electrocatalytic oxidation of organic small molecules.The interaction between Ni and Co can optimize the electronic structure,resulting in the improved conductivity and accelerated charge transfer rate.The 2D/3D architecture can enrich more active species and endow the mass and electron transport to facilitate the surface oxidation and the following catalytic process.Post-structure and catalytic characterizations confirm the surface oxidation of(Ni,Co)S_(2)during the stability test,and the in-situ formed Co(Ni)based(oxy)hydroxides exhibit superior catalytic activity and facilitated charge transfer ability.As a result,the optimal(Ni,Co)S_(2)solid solution pre-catalyst displays facilitated catalytic behavior and good stability for multifunctional electrocatalytic oxidation,in which a high conversion of benzyl alcohol(97.50%),a good selectivity to benzoic acid(93.78%)and a satisfied faraday efficiency(91.86%)can be achieved.
基金This work was jointly supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project(No.HZQB-KCZYB-2020030)the National Key R&D Program of China(Project No.2017YFA0204403)Innovation and Technology Commission of HKSAR through Hong Kong Branch of National Precious Metals Material Engineering Research Centre and Shenzhen Science and Technology Innovation Committee(No.JCYJ20200109113212238).
文摘Fabrication of single-crystalline metal-organic framework(MOF)hollow nanostructures with two-dimensional(2D)morphologies is a challenging task.Herein,twin-like MOF nanobricks,a quasi-hollow 2D architecture,with multi-metal nodes and replaceable organic ligands,are uniformly and firmly grown on conductive Ni foam through a generic one-pot approach.The formation process of twin-like MOF nanobricks mainly includes selective epitaxial growth of Fe-rich MOF layer and simultaneously dissolution of the pre-formed Ni-rich metal-organic frameworks(MOFs),all of which can be ascribed to a special self-templated mechanism.The fantastic structural merits of twin-like MOF nanobrick arrays,featuring highly exposed active sites,remarkable electrical conductivity,and hierarchical porosities,enable this material for efficient electrocatalysis.Using bimetallic NiFe-MOFs grown on Ni foam as an example,the resultant twin-like nanobrick arrays can be directly utilized as three-dimensional(3D)integrated electrode for high-performance water oxidation in 1 M KOH with a low overpotential,fast reaction kinetics(28.5 mV·dec^(-1)),and superb stability.Interestingly,the unstable NiFe-MOFs were served as an oxygen evolution reaction(OER)pre-catalyst and the single-crystalline NiFe-MOF precursor can be in-situ topochemically regulated into porous and lowcrystalline NiFeOx nanosheets during the OER process.This work extends the hollowing strategy to fabricate hollow MOFs with 2D architectures and highlights their direct utilization for advanced electrocatalysis.
基金financially supported by National Natural Science Foundation of China(22278170,52172058)Natural Science Foundation of Anhui Province(2408085QB037)+3 种基金Natural Science Foundation of Anhui Provincial Department of Education(2023AH020042,2024AH051721)financial support from High-Level Talents Introduction and Cultivation Plan of Anhui Province-Young Top Talent,Huainan Innovation and Entrepreneurship Star Team(HNSTD-2024),Huainan Research Center of New Carbon Energy Materials(HNSPT02)New Energy Materials and Technology Research Center of Huainan Normal University.Business Finland,BATCircle2.0 project(Grant No.44612/31/2020)is acknowledged for financial supportU.L.acknowledges Finnish Research Impact Foundation for Tandem Industry Academy Professorship funding in 2023-2025.
文摘Amorphous transition metal compounds(a-TMC)become one of the most promising pre-catalysts toward oxygen evolution reaction(OER)due to their high-entropy nature and flexible self-reconstruction to highly active derivatives.However,the loosen bonds inside the amorphous structure make it an electronic insulator with unstable structure.Here,monodispersed Ni^(2+)-phytate nanospheres implanted by Fe^(3+)ions(NS_(FeNiPA))were firstly prepared and subsequently transferred into homogeneous high-entropy type Fe-Ni-P-O-C amorphous nanospheres(CNS_(FeNiPO)).It is shown that the CNS_(FeNiPO) presents robust structure and remarkable Fe ions migration during potential-driven activation process,which benefits efficient surface reconstruction and spherical morphology preservation.The CNS_(FeNiPO) with low mass loading of 0.1mg/cm^(2)could deliver small overpotential of 270mV at 10mAcm^(−2)and almost 100%retention of the initial current density after 10h test.The improved electrocatalytic activity is attributed to the boosted electron transfer from Ni sites to O-containing intermediates by introduction of Fe and P atoms.Moreover,rechargeable Zn-air battery with CNS_(FeNiPO)+Pt/C could achieve lower charge potential platform and better cycling performance than that with commercial RuO_(2)+Pt/C.This work provides new insights into the design and understanding of high-entropy amorphous pre-catalysts toward OER.
基金supported by the National Natural Science Foundation of China (No.22179014)the China Postdoctoral Science Foundation (No.2022 M720593)+2 种基金the Scientific Research Foundation of Chongqing University of Technology (Nos.2022ZDZ011,2022PYZ026)the Youth Project of Science and Technology Research Program of Chongqing Municipal Education Commission (No.KJQN202201127)the Project of Natural Science Foundation of Chongqing (No.2022NSCQ-MSX1123)。
文摘The development of inexpensive and efficient electrocatalysts is key to commercializing energy-related electrocatalytic techniques such as water electrolyzers and metal-air batteries.In particular,novel oxygen evolution reaction(OER)pre-catalysts,such as transition metal chalcogenides(TMCs)and phosphides(TMPs),have evolved in recent years from traditional stable OER electrocatalysts,which show superior OER electrocatalytic performance compared with transition metal oxides(TMOs)or(oxy)hydroxides(TMOHs).In this feature article,we summarize recent advances in the development of TMCand TMP-based OER electrocatalysts,as well as approaches to improve the OER performance in terms of morphology,structure,composition,surface engineering,lattice-strained and in-situ transformation in the electrolysis process.In particular,the electrochemical stability of TMCs and TMPs in alkaline electrolytes and the evolution of morphology,structure and composition under OER conditions are discussed.In the last section,we discuss the challenges that need to be addressed in this specific area of research and the implications for further research.
基金This work was financially supported by the Chemistry and Chemical Engineering Guangdong Laboratory(Nos.2111018 and 2132012)Q.M.would like to express gratitude towards the Foreign Youth Talent Program(No.QN2022030008L)for their support.
文摘For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but challenging.In this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction conditions.Upon activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches.The catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride counterparts.The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break.Particularly,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).
基金supported by the National Natural Science Foundation of China(Nos.52122308 and 22305225)the Postdoctoral Fellowship Program of CPSF(No.GZC20232391).
文摘The development of sustainable hydrogen production technologies is critical to addressing the global energy crisis and environmental challenges.Among water electrolysis systems,anion-exchange membrane water electrolyzers(AEMWEs)have gained attention for their ability to combine cost-effectiveness with high efficiency.However,AEMWEs face challenges such as sluggish oxygen evolution reaction(OER)catalysts with low conductivity and density of active sites,especially with the feed stock of pure water.In this study,a tri-metal Prussian blue analogue(PBA)was synthesized at room temperature and employed as an efficient OER pre-catalyst.Electrochemical activation of this as-prepared material in the alkaline solution generates highly active and conductive crystalline-amorphous metal(oxy)hydroxides as the true catalytic sites,which exhibited exceptional OER performance with the overpotential of 251 mV at 10 mA·cm^(-2) and stable operation for 500 h in the alkaline solution.When applied as anode in AEMWEs,it delivered 1 A·cm^(-2) at 1.72 and 2.20 V with the feedstock of alkaline solution(1 M KOH)and pure water,respectively,demonstrating its large application prospect in AEMWE.
基金supported by National Natural Science Foundation of China(Nos.52073199 and 52274304)。
文摘The rational design of high-performance bifunctional electrocatalysts for overall water splitting(OWS)is the key to popularize hydrogen production technology.The active metal oxyhydroxide(MOOH)formed after surface self-reconfiguration of transition metal sulfide(TMS)electrocatalyst is often regarded as the"actual catalyst"in oxygen evolution reaction(OER).Herein,an Fe doped Co S2/Mo S2hollow TMS polyhedron(Fe-Co S2/Mo S2)with rich Mott-Schottky heterojunction is reported and directly utilized as an OWS electrocatalyst.The spontaneous built-in electric field(BEF)at the heterogeneous interface regulates the electronic structure and D-band center of the catalyst.More importantly,the“TMS-MOOH”core-shell structure obtained in the KOH electrolyte shows enhanced OER properties.And the introduction of Fe ions activates the inert basal plane of Mo S2,which greatly steps up the performance of HER.Hence,the preferable Fe-CoS_(2)/MoS_(2)–400 presents superior OER activity(η_(10)=178 m V,η_(100)=375 m V),HER activity(η_(10)=92 m V)and ultra-high stability for 50 h.This work has deeply explored the catalytic mechanism of TMS and provided a new idea for the construction of efficient bifunctional catalysts.
基金funded by the financial support from the Start-up Foundation of Shanghai Institute of Ceramics,Chinese Academy of Sciences(Nos.E03ZZ51501 and E11YB5150G)the financial support by the Natural Science Foundation of Shanghai(No.22ZR1471900)+1 种基金Shanghai Qimingxing Project(No.22QA1410300),Shanghai Municipal Science and Technology Commission of Carbon Peak&Carbon Neutrality Project(No.21DZ1207900)the Hundred Talents Program of the Chinese Academy of Sciences(Nos.E13ZB313 and E11YB515).
文摘Developing high-efficiency and low-cost oxygen evolution reaction(OER)catalysts is crucial to advance the water splitting technology for sustainable hydrogen production.Here,a FeCoNi coordinated benzene-1,3,5-tricarboxylic acid(FeCoNiBTC)metal-organic framework(MOF)was synthesized by one-step solvothermal method for OER.A rapid in-situ chemical and electrochemical transformation was observed on the surface of the FeCoNiBTC MOF during OER process.The formed catalytic active FeCoNiOx(OH)y species retained the unique structure feature of initial FeCoNiBTC,moreover,it possessed multiple transition metal active nodes that cooperate with each other to adjust the electronic structure.Owing to the above structure advantages,the in-situ transformed FeCoNiOx(OH)y showed excellent OER catalytic activity with a small overpotential of 230 mV to achieve the 100 mA·cm^(−2),a low Tafel slope of 50.2 mV·dec^(−1),and superior stability of almost 80 h in alkaline aqueous solution.This work systematically studies the structure-performance relations of the multi-metal MOF-based materials in OER process,and it would enrich the exploration of highly efficient OER electrocatalysts.
基金supported by the National Key R&D Program of China(2023YFD1701502)Key Technologies Equipment and Product Development for Efficient Utilization of Rural Wastes(CAAS-ZDRW202510.2).
文摘A new two-stage catalytic system was developed to overcome the problems of low yield of hydrogenrich gas and serious carbon deposition on the catalyst during biomass pyrolysis catalysis.The operating temperature,catalyst type and catalyst addition ratio were compared,and the optimum hydrogen production conditions were obtained(with yield reaching 52.21 wt%and the hydrogen yield reaching 29.15 vol%).The catalysts were modified by metals,including Ni,Ni-Co,Ni-Fe,Ni-Mo and Ni-Ce.Ni-Ce/Al_(2)O_(3)exhibited the highest tar-cracking efficiency during one-stage catalysis,attributed to the redox cycle between Ce^(3+)/Ce^(4+).In order to further improve the catalytic performance,the biochar pre-catalytic layer with rich porous structure and surface functional groups was introduced.Macromolecular volatiles were selectively adsorbed by the pre-catalyst and promoted in chain reactions.Macromolecular volatiles were selectively adsorbed by the pre-catalyst,in which the tar reforming reaction was promoted,resulting in an increase in hydrogen production to 29.76-48.87 vol%in two-stage catalysis.In addition,Biochar pre-catalyst promoted free radical recombination by enhancing the formation of H_(2)and H·and reducing the binding of polycyclic aromatic hydrocarbons,which effectively inhibited carbon deposition.This study provides theoretical insights and proposes a novel stepwise catalytic strategy for efficient hydrogen production from biomass,highlighting its potential for practical energy conversion applications.
文摘In this study,post-consumer low-density polyethylene packaging waste was converted via plasma-assisted and conventional thermal pyrolysis,respectively.A perovskite-type La_(0.6)Ca0.4Co_(0.2)Fe_(0.8)O_(3−δ)pre-catalyst was employed to simultaneously generate hydrogen and carbon nanomaterials.The plasma-thermal catalytic process demonstrated superior conversion efficiency for both gaseous and solid products compared to the two-stage thermal catalytic approach.To evaluate the potential of the synthesized carbon nanotube composites for low-grade energy storage applications,the metal oxide-carbon composites obtained from both synthesis methods were employed as a host for sulfur cathodes in lithium-sulfur batteries.Electrochemical analysis demonstrated comparable cycling stability between the two approaches,with initial discharge capacities of 296 and 291 mAh g^(−1),which stabilized at 125 and 112 mAh g^(−1)after 50 cycles at a 0.05 C(1C=1675 mAh g^(−1))rate for the plasma-thermal and thermal catalytic processes,respectively.These results highlight the feasibility of directly incorporating the derived carbon nanotube composites into energy storage technologies,offering a potentially sustainable route for large-scale plastic waste valorization and advanced material development.
