Designing high-performance electrocatalysts toward hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is essential to reduce the activation barrier and optimize free adsorption energy of reactive interm...Designing high-performance electrocatalysts toward hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is essential to reduce the activation barrier and optimize free adsorption energy of reactive intermediates.Herein,we report that incorporating high-valence Cr into NiSe_(2)(Cr_(x)Ni_(1-x)Se_(2))kinetically and thermodynamically expedites elementary steps of both HER and OER.The as-prepared Cr_(0.05)Ni_(0.95)Se_(2) catalyst displays excellent HER and OER activities,with low overpotentials of 89 and 272 mV at the current density of 10 mA·cm^(-2)(j10),respectively,and remains stable during operation for 30 h.A low cell voltage of only 1.59 V is required to drive j10 in alkaline media.In situ Raman spectroscopy reveals that Cr incorporation facilitates the formation of NiOOH active species during the OER process.Meanwhile,theoretical explorations demonstrate that high-valence Cr incorporation efficiently accelerates water dissociation kinetics and improves H*adsorption during HER process,lowering the activation barrier of OER and optimizing the adsorption energy of oxygen-based intermediate,thus kinetically and thermodynamically enhancing the intrinsic performance of NiSe_(2) for over water splitting.This strategy provides a new horizon to design transition metal based electrocatalysts in the clean energy field.展开更多
Developing high-efficiency electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is required to enhance the sluggish kinetics of water dissociation and optimize the adsorption free e...Developing high-efficiency electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is required to enhance the sluggish kinetics of water dissociation and optimize the adsorption free energy of reaction intermediates.Herein,we tackle this challenge by incorporating high-valence Zr into CoP(ZrxCo_(1-x)P),which significantly accelerates the elementary steps of water electrolysis.Theoretical calculations indicate that the appropriate Zr incorporation effectively expedites the sluggish H2O dissociation kinetics and optimizes the adsorption energy of reaction intermediates for boosting the alkaline water electrolysis.These are confirmed by the experimental results of Zr_(0.06)Co_(0.94)P catalyst that delivers exceptional electrochemical activity.The overpotentials at the current density of 10 mA cm^(-2)(j10) are only 62(HER) and 240 mV(OER) in alkaline media.Furthermore,the Zr_(0.06)Co_(0.94)P/CC‖Zr_(0.06)Co_(0.94)P/CC system exhibits superior overall water splitting activity(1.53 V/j10),surpassing most of the reported bifunctional catalysts.This high-valence Zr incorporation and material design methods explore new avenues for realizing high-performance non-noble metal electrocatalysts.展开更多
Among various earth-abundant and noble metal-free catalysts for oxygen reduction reaction(ORR),manganese-based oxides are promising candidates owing to the rich variety of manganese valence.Herein,an extremely facile ...Among various earth-abundant and noble metal-free catalysts for oxygen reduction reaction(ORR),manganese-based oxides are promising candidates owing to the rich variety of manganese valence.Herein,an extremely facile method for the synthesis of cubic and orthorhombic phase coexisting Mn(Ⅱ)O electrocatalyst as an efficient ORR catalyst was explored.The obtained MnO electrocatalyst with oxygen vacancies shows a significantly elevated ORR catalytic activity with a half-wave potential(E1/2) of as high as 0.895 V,in comparison with that of commercial Pt/C(E1/2=0.877 V).More impressively,the MnO electrocatalyst exhibits a marked activity enhancement after test under a constant applied potential for 1000 s thanks to the in situ generation and stable presence of high-valence manganese species(Mn^3+ and Mn^4+) during the electrochemical process,initiating a synergetic catalytic effect with oxygen vacancies,which is proved to largely accelerate the adsorption and reduction of O_2 molecules favoring the ORR activity elevation.Such an excellent ORR catalytic performance of this MnO electrocatalyst is applied in Zn-air battery,which shows an extra-high peak power density of 63.2 mW cm^-2 in comparison with that(47.4 m W cm^-2) of commercial Pt/C under identical test conditions.展开更多
A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe lea...A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe leads to substantively enhanced OER activity.However,the critical role of Fe species during the electrocatalytic process is still under evaluation.Herein,we report nickel(oxy)hydroxide incorporated with Fe through the surface reconstruction of a bimetallic metal-organic framework(NiFe-MOF)during the water oxidation process.The spectroscopic investigations with theoretical calculations reveal the critical role of Fe in promoting the formation of highly oxidized Ni^(4+),which directly correlates with an enhanced OER activity.Both the geometric and electronic structu res of the as-reconstructed Ni_(1-x)Fe_(x)OOH electrocatalysts can be delicately tuned by the Ni-Fe ratio of the bimetallic NiFe-MOF,further affecting the catalytic activity.As a result,the Ni_(1-x)Fe_(x)OOH derived from Ni_(0.9)Fe_(0.1)-MOF delivers low overpotentials of 260 mV at 10 mA cm^(-2)and 400 mV at 300 mA cm^(-2).展开更多
Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensi...Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensional(3D)honeycomb-like cobalt sulfide(Co_(x)S_(y))network organized by cross-linked nanosheets(Co_(x)S_(y)-T NSs)was prepared via a simple triethanolamine(TEOA)-assisted self-templating strategy.Interestingly,it has been found for the first time that the introduction of TEOA in the reaction effectively increases the ratio of high-valence Co^(3+)in the final product.Benefiting from the synergetic effect of the tailored high-valence Co^(3+)with the 3D network structure,the Co_(x)S_(y)-T NS electrode exhibits a maximum specific capacity of 351 mA h g^(-1)(2635 F g^(-1))at 5 A g^(-1)as well as excellent cycling stability.Furthermore,with the solid-state asymmetric supercapacitor(ASC)constructed based on the Co_(x)S_(y)-T NSs and activated carbon(AC)electrodes,a high energy density up to 81.62 W h kg^(-1)has been achieved at the power density of 0.81 kW kg^(-1)and 96.2%capacitance is preserved after 7000 cycles,indicating robust cycling stability.This result highlights the simple approach of simultaneously tailoring highvalence metal species and constructing 3D network structure toward high-performance electrode materials for energy storage and conversion.展开更多
Developing efficient and durable non-noble metal-based oxygen evolution catalysts is of great importance for electrochemical water splitting.Here,we report a new and facile strategy for controllable synthesis of high-...Developing efficient and durable non-noble metal-based oxygen evolution catalysts is of great importance for electrochemical water splitting.Here,we report a new and facile strategy for controllable synthesis of high-valence Mo modified FeNiV oxides as efficient OER catalysts.The Mo-dopant displays a significant influence on the valence state of Fe species in the catalysts,which lead to tunable OER performance.When the feed ratio of Mo-dopant is 5%,the Mo-modified FeNiV oxide shows the best OER performance in terms of low overpotential(237 mV at the current density of 10 mA cm^(−2)),Tafel slope(38 mV per decade),and high mass activity,which exceeds its counterparts and most reported OER catalysts.Furthermore,by assembling the catalyst with a carbon fiber cloth,the fabricated water-splitting device exhibits excellent activity and longterm durability in alkaline electrolyte compared with commercial catalysts equipped device.This work not only provides a series of Mo-modified FeNiV-based oxides as high-performance OER catalysts but also offers a new pathway to tune the charge states of OER active centers.展开更多
Metal-organic frameworks(MOFs) possess the features of highly porosity-tunable and electronic-tunable structures,. Taking advantages of these merits, we successfully installed high-valence W6+ions onto the Ti-oxo clus...Metal-organic frameworks(MOFs) possess the features of highly porosity-tunable and electronic-tunable structures,. Taking advantages of these merits, we successfully installed high-valence W6+ions onto the Ti-oxo clusters of MIL-125(Ti)(W-MIL-125). The installed W^(6+) ions which form a W–O–Ti structure trigger the metal-to-cluster charge transfer(MCCT), together with an enhanced light absorption.Structural and spectroscopic characterizations reveal that the MCCT process optimizes the charge transfer process and efficiently separates the photogenerated electron-hole spatially.The as-obtained sample of 3.45 W-MIL-125 with optimized electronic structure demonstrates an enhanced photocatalytic hydrogen evolution performance of 1110.7 ± 63.7 μmol g^(-1)h^(-1) under light irradiation, which is 4.0 times that of the pristine MIL-125(Ti). This work will open up a new avenue for local structural modification of MOFs to boost photocatalytic performance.展开更多
氢能作为一种潜在的能源载体,有望取代化石燃料,解决当今社会的能源需求和环境问题.质子交换膜电解水(PEMWE)技术因其工作电流密度大、氢气纯度高和系统响应迅速等优点,能够有效地弥补可再生能源波动性等缺点,被认为是一种利用可再生能...氢能作为一种潜在的能源载体,有望取代化石燃料,解决当今社会的能源需求和环境问题.质子交换膜电解水(PEMWE)技术因其工作电流密度大、氢气纯度高和系统响应迅速等优点,能够有效地弥补可再生能源波动性等缺点,被认为是一种利用可再生能源制氢的可持续手段.但其阳极氧析出反应(OER)为四电子/质子转移过程,反应动力学缓慢,同时强氧化性和强酸性环境会对阳极催化剂的产生腐蚀,导致稳定性差,因此亟需开发高效且稳定的催化剂.研究发现,无定型氧化铱材料中的特殊缺陷结构可显著提升其催化酸性OER的活性,但该结构也会加速反应过程中铱的溶解,导致催化剂稳定性降低,严重限制了其实际应用.本文采用高价金属掺杂的策略,利用高价金属元素与氧的强成键作用,对无定型氧化铱的整体结构及活性位点起到优化且稳定的作用.首先,采用改性的亚当斯熔融法制备了金属钽掺杂的无定型氧化铱:350-Ta@IrO_(x),400-Ta@IrO_(x),450-Ta@IrO_(x)(350,400和450代表样品分别在350,400和450℃烧结),并用于催化酸性OER;作为对比,制备了无掺杂的无定型氧化铱:350-IrO_(x),400-IrO_(x)和450-IrO_(x).然后,通过扫描电子显微镜、透射电子显微镜(TEM)和X射线衍射等表征技术考察了材料的宏观形貌及微观结构.结果表明,掺杂后的350-Ta@IrO_(x)材料表面具有丰富的氧空位贡献的活性位点,且表现出多晶的超小纳米颗粒形貌.电化学测试结果表明,350-Ta@IrO_(x)具有较好的酸性OER活性,在10 mA cm-2的电流密度下,过电势仅为223 mV,在1.55 V vs.RHE的电位下质量活性为1207.4 A gIr-1,是商业二氧化铱的147.7倍.且该催化剂的稳定性比未掺杂Ta样品及商业二氧化铱有明显提升,在0.5 mol L^(-1)硫酸溶液中反应500 h后电位未发生明显变化.密度泛函理论计算结果表明,Ta掺杂与构建缺陷有利于OER决速步中水分子的亲核进攻,从而提升催�展开更多
基金supported by the National Natural Science Foundation of China(Nos.12034002,22279044,and 22202080)Jilin Province Science and Technology Development Program(No.20210301009GX)the fellowship of China Postdoctoral Science Foundation(No.2022M711296).
文摘Designing high-performance electrocatalysts toward hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is essential to reduce the activation barrier and optimize free adsorption energy of reactive intermediates.Herein,we report that incorporating high-valence Cr into NiSe_(2)(Cr_(x)Ni_(1-x)Se_(2))kinetically and thermodynamically expedites elementary steps of both HER and OER.The as-prepared Cr_(0.05)Ni_(0.95)Se_(2) catalyst displays excellent HER and OER activities,with low overpotentials of 89 and 272 mV at the current density of 10 mA·cm^(-2)(j10),respectively,and remains stable during operation for 30 h.A low cell voltage of only 1.59 V is required to drive j10 in alkaline media.In situ Raman spectroscopy reveals that Cr incorporation facilitates the formation of NiOOH active species during the OER process.Meanwhile,theoretical explorations demonstrate that high-valence Cr incorporation efficiently accelerates water dissociation kinetics and improves H*adsorption during HER process,lowering the activation barrier of OER and optimizing the adsorption energy of oxygen-based intermediate,thus kinetically and thermodynamically enhancing the intrinsic performance of NiSe_(2) for over water splitting.This strategy provides a new horizon to design transition metal based electrocatalysts in the clean energy field.
基金National Natural Science Foundation of China (22202080,51872116, 12034002)the fellowship of China Postdoctoral Science Foundation (2022 M711296)the Jilin Province Science and Technology Development Program (20210301009GX)。
文摘Developing high-efficiency electrocatalysts for hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is required to enhance the sluggish kinetics of water dissociation and optimize the adsorption free energy of reaction intermediates.Herein,we tackle this challenge by incorporating high-valence Zr into CoP(ZrxCo_(1-x)P),which significantly accelerates the elementary steps of water electrolysis.Theoretical calculations indicate that the appropriate Zr incorporation effectively expedites the sluggish H2O dissociation kinetics and optimizes the adsorption energy of reaction intermediates for boosting the alkaline water electrolysis.These are confirmed by the experimental results of Zr_(0.06)Co_(0.94)P catalyst that delivers exceptional electrochemical activity.The overpotentials at the current density of 10 mA cm^(-2)(j10) are only 62(HER) and 240 mV(OER) in alkaline media.Furthermore,the Zr_(0.06)Co_(0.94)P/CC‖Zr_(0.06)Co_(0.94)P/CC system exhibits superior overall water splitting activity(1.53 V/j10),surpassing most of the reported bifunctional catalysts.This high-valence Zr incorporation and material design methods explore new avenues for realizing high-performance non-noble metal electrocatalysts.
基金the support of this research by Natural Science Foundation of Shanghai (19ZR1479400)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University (KF1818)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technology)。
文摘Among various earth-abundant and noble metal-free catalysts for oxygen reduction reaction(ORR),manganese-based oxides are promising candidates owing to the rich variety of manganese valence.Herein,an extremely facile method for the synthesis of cubic and orthorhombic phase coexisting Mn(Ⅱ)O electrocatalyst as an efficient ORR catalyst was explored.The obtained MnO electrocatalyst with oxygen vacancies shows a significantly elevated ORR catalytic activity with a half-wave potential(E1/2) of as high as 0.895 V,in comparison with that of commercial Pt/C(E1/2=0.877 V).More impressively,the MnO electrocatalyst exhibits a marked activity enhancement after test under a constant applied potential for 1000 s thanks to the in situ generation and stable presence of high-valence manganese species(Mn^3+ and Mn^4+) during the electrochemical process,initiating a synergetic catalytic effect with oxygen vacancies,which is proved to largely accelerate the adsorption and reduction of O_2 molecules favoring the ORR activity elevation.Such an excellent ORR catalytic performance of this MnO electrocatalyst is applied in Zn-air battery,which shows an extra-high peak power density of 63.2 mW cm^-2 in comparison with that(47.4 m W cm^-2) of commercial Pt/C under identical test conditions.
基金supported by the National Natural Science Foundation of China(22105060)the Natural Science Foundation of Hebei Province(E2020205004)+1 种基金Funding from the Science Foundation of Hebei Normal University(L2020B13)the Science and Technology Project of Hebei Education Department(BJ2021028)。
文摘A mixture of Ni and Fe oxides is among the most commonly active catalysts for the oxygen evolution reaction(OER)during the water oxidation process.In particular,Ni oxide incorporated with even a small amount of Fe leads to substantively enhanced OER activity.However,the critical role of Fe species during the electrocatalytic process is still under evaluation.Herein,we report nickel(oxy)hydroxide incorporated with Fe through the surface reconstruction of a bimetallic metal-organic framework(NiFe-MOF)during the water oxidation process.The spectroscopic investigations with theoretical calculations reveal the critical role of Fe in promoting the formation of highly oxidized Ni^(4+),which directly correlates with an enhanced OER activity.Both the geometric and electronic structu res of the as-reconstructed Ni_(1-x)Fe_(x)OOH electrocatalysts can be delicately tuned by the Ni-Fe ratio of the bimetallic NiFe-MOF,further affecting the catalytic activity.As a result,the Ni_(1-x)Fe_(x)OOH derived from Ni_(0.9)Fe_(0.1)-MOF delivers low overpotentials of 260 mV at 10 mA cm^(-2)and 400 mV at 300 mA cm^(-2).
基金the National Natural Science Foundation of China(21671173)Zhejiang Provincial Ten Thousand Talent Program(2017R52043)。
文摘Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensional(3D)honeycomb-like cobalt sulfide(Co_(x)S_(y))network organized by cross-linked nanosheets(Co_(x)S_(y)-T NSs)was prepared via a simple triethanolamine(TEOA)-assisted self-templating strategy.Interestingly,it has been found for the first time that the introduction of TEOA in the reaction effectively increases the ratio of high-valence Co^(3+)in the final product.Benefiting from the synergetic effect of the tailored high-valence Co^(3+)with the 3D network structure,the Co_(x)S_(y)-T NS electrode exhibits a maximum specific capacity of 351 mA h g^(-1)(2635 F g^(-1))at 5 A g^(-1)as well as excellent cycling stability.Furthermore,with the solid-state asymmetric supercapacitor(ASC)constructed based on the Co_(x)S_(y)-T NSs and activated carbon(AC)electrodes,a high energy density up to 81.62 W h kg^(-1)has been achieved at the power density of 0.81 kW kg^(-1)and 96.2%capacitance is preserved after 7000 cycles,indicating robust cycling stability.This result highlights the simple approach of simultaneously tailoring highvalence metal species and constructing 3D network structure toward high-performance electrode materials for energy storage and conversion.
基金National Natural Science Foundation of China(Nos.52173133,51903178,81971622,and 51803134)the Science and Technology Project of Sichuan Province(2021YFH0135,2020YJ0055,and 2020YFH0087)+4 种基金China Postdoctoral Science Foundation(2021M692303)the Post-Doctor Research Project of Sichuan University(No.2021SCU12013)the 1・3・5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(No.ZYJC21047)Prof.Cheng acknowledges the financial support of the State Key Laboratory of Polymer Materials Engineering(Grant No.sklpme2021-4-02)Fundamental Research Funds for the Central Universities,and Thousand Youth Talents Plan.Dr.S.Li acknowledges the financial support by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Basismodul,Eigene Stelle(LI 3545/1-1).
文摘Developing efficient and durable non-noble metal-based oxygen evolution catalysts is of great importance for electrochemical water splitting.Here,we report a new and facile strategy for controllable synthesis of high-valence Mo modified FeNiV oxides as efficient OER catalysts.The Mo-dopant displays a significant influence on the valence state of Fe species in the catalysts,which lead to tunable OER performance.When the feed ratio of Mo-dopant is 5%,the Mo-modified FeNiV oxide shows the best OER performance in terms of low overpotential(237 mV at the current density of 10 mA cm^(−2)),Tafel slope(38 mV per decade),and high mass activity,which exceeds its counterparts and most reported OER catalysts.Furthermore,by assembling the catalyst with a carbon fiber cloth,the fabricated water-splitting device exhibits excellent activity and longterm durability in alkaline electrolyte compared with commercial catalysts equipped device.This work not only provides a series of Mo-modified FeNiV-based oxides as high-performance OER catalysts but also offers a new pathway to tune the charge states of OER active centers.
基金financially supported by the National Natural Science Funds for Distinguished Young Scholars (51725201)the International (Regional) Cooperation and Exchange Projects of the National Natural Science Foundation of China (51920105003)+6 种基金the Innovation Program of Shanghai Municipal Education Commission (E00014)China Postdoctoral Science Foundation Funded Project (2020M681201)Shanghai Engineering Research Center of Hierarchical Nanomaterials (18DZ2252400)the Fundamental Research Funds for the Central Universities (JKD01211519)the support by Shanghai Rising-star Program (20QA1402400)the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learningprovided by the Feringa Nobel Prize Scientist Joint Research Center。
文摘Metal-organic frameworks(MOFs) possess the features of highly porosity-tunable and electronic-tunable structures,. Taking advantages of these merits, we successfully installed high-valence W6+ions onto the Ti-oxo clusters of MIL-125(Ti)(W-MIL-125). The installed W^(6+) ions which form a W–O–Ti structure trigger the metal-to-cluster charge transfer(MCCT), together with an enhanced light absorption.Structural and spectroscopic characterizations reveal that the MCCT process optimizes the charge transfer process and efficiently separates the photogenerated electron-hole spatially.The as-obtained sample of 3.45 W-MIL-125 with optimized electronic structure demonstrates an enhanced photocatalytic hydrogen evolution performance of 1110.7 ± 63.7 μmol g^(-1)h^(-1) under light irradiation, which is 4.0 times that of the pristine MIL-125(Ti). This work will open up a new avenue for local structural modification of MOFs to boost photocatalytic performance.
文摘氢能作为一种潜在的能源载体,有望取代化石燃料,解决当今社会的能源需求和环境问题.质子交换膜电解水(PEMWE)技术因其工作电流密度大、氢气纯度高和系统响应迅速等优点,能够有效地弥补可再生能源波动性等缺点,被认为是一种利用可再生能源制氢的可持续手段.但其阳极氧析出反应(OER)为四电子/质子转移过程,反应动力学缓慢,同时强氧化性和强酸性环境会对阳极催化剂的产生腐蚀,导致稳定性差,因此亟需开发高效且稳定的催化剂.研究发现,无定型氧化铱材料中的特殊缺陷结构可显著提升其催化酸性OER的活性,但该结构也会加速反应过程中铱的溶解,导致催化剂稳定性降低,严重限制了其实际应用.本文采用高价金属掺杂的策略,利用高价金属元素与氧的强成键作用,对无定型氧化铱的整体结构及活性位点起到优化且稳定的作用.首先,采用改性的亚当斯熔融法制备了金属钽掺杂的无定型氧化铱:350-Ta@IrO_(x),400-Ta@IrO_(x),450-Ta@IrO_(x)(350,400和450代表样品分别在350,400和450℃烧结),并用于催化酸性OER;作为对比,制备了无掺杂的无定型氧化铱:350-IrO_(x),400-IrO_(x)和450-IrO_(x).然后,通过扫描电子显微镜、透射电子显微镜(TEM)和X射线衍射等表征技术考察了材料的宏观形貌及微观结构.结果表明,掺杂后的350-Ta@IrO_(x)材料表面具有丰富的氧空位贡献的活性位点,且表现出多晶的超小纳米颗粒形貌.电化学测试结果表明,350-Ta@IrO_(x)具有较好的酸性OER活性,在10 mA cm-2的电流密度下,过电势仅为223 mV,在1.55 V vs.RHE的电位下质量活性为1207.4 A gIr-1,是商业二氧化铱的147.7倍.且该催化剂的稳定性比未掺杂Ta样品及商业二氧化铱有明显提升,在0.5 mol L^(-1)硫酸溶液中反应500 h后电位未发生明显变化.密度泛函理论计算结果表明,Ta掺杂与构建缺陷有利于OER决速步中水分子的亲核进攻,从而提升催�
