Hematite is regarded as a promising photoanode for photoelectrochemical(PEC) water splitting.However,the charge recombination occurred at the interface of FTO/hematite strictly limits the PEC performance of hematite.H...Hematite is regarded as a promising photoanode for photoelectrochemical(PEC) water splitting.However,the charge recombination occurred at the interface of FTO/hematite strictly limits the PEC performance of hematite.Herein,we reported a Ti3C2 MXene underlayer modified hematite(Ti-Fe2O3) photoanode via a simple drop-casting followed by hydrothermal and annealing processes.Owing to the bifunctional role of Ti3C2 MXene underlayer in improving the interfacial properties of FTO/hematite and providing Ti source for the construction of Fe2 TiO5/Fe2O3 heterostructure in hematite nanostructure,the bulk and interfacial charge transfer dynamics of hematite are significantly enhanced,and consequently enhancing the PEC performance.Compared with the pristine hematite,the as-prepared Ti-Fe2O3 photoanode shows an increased photocurrent density from 0.80 mA/cm^(2) to 1.30 mA/cm^(2) at 1.23 V vs.RHE.Moreover,a further promoted PEC performance including a dramatically increased photocurrent density of 2.49 mA/cm^(2) at1.23 V vs.RHE and an obviously lowered onset potential is achieved for the Ti-Fe2O3 sample after the subsequent surface F-treatment and the loading of FeNiOOH cocatalyst.Such results suggest that the introduction of Ti3C2 MXene underlayer is a facile but effective approach to improve the PEC water splitting activity of hematite.展开更多
MXene stands out as a rising family of transition metal carbides/nitrides with exceptional size-dependent properties and versatile potential applications. However, the realization of large MXene with a controllable su...MXene stands out as a rising family of transition metal carbides/nitrides with exceptional size-dependent properties and versatile potential applications. However, the realization of large MXene with a controllable surface at atomic level remains challenging to keep the balance among the conductivity, stability and activity. Herein, the horizontal oscillation-induced delamination(HOD)strategy is proposed to acquire Ti_(3)C_(2) flakes with large size and low Ti–Ti coordination(HO-Ti_(3)C_(2)). The average size of the asobtained flakes can reach 6.48 μm to keep the overall conductive skeleton and merits from large size. Simultaneously, metal atoms at surface can be partially removed due to the enhanced local vibrational turbulence during the reciprocating horizontal oscillation process. Such MXenes with clear and unique surface states exhibit high potentials in ion adsorption together with satisfied electric conductivity and stability. As proof of concept, HO-Ti_(3)C_(2) anode exhibits remarkable rate capability and longterm stability during sodium storage. A capacity of 100.5 m Ah g^(-1)with a long-life cycle(4,500 cycles) at a high rate of 1.0 A g^(-1)originates from the increased s-d interaction between Na and Ti. Therefore, the HOD strategy provides a controllable surface design to promote the clear criteria into size-dependent research on MXene.展开更多
Breakthroughs in energy storage and conversion devices depend heavily on the exploration of low-cost and high-performance materials.Carbon-supported electrocatalysts with dimensional varieties have recently attracted ...Breakthroughs in energy storage and conversion devices depend heavily on the exploration of low-cost and high-performance materials.Carbon-supported electrocatalysts with dimensional varieties have recently attracted significant attention due to their strong structural flexibility and easy accessibility.Nevertheless,understanding the connection between their electronic,structural properties,and catalytic performance must remain a top priority.Synchrotron radiation(SR)X-ray absorption spectroscopy(XAS)techniques,including hard XAS and soft XAS,are recognized as efficient and comprehensive platforms for probing the surface,interface,and bulk electronic structure of elements of interest in the materials community.In the past decade,the flourishing development of materials science and advanced characterization technologies have led to a deeper understanding at different temporal,longitudinal,and spatial scales.In this review,we briefly describe the concept of XAS techniques and summarize their recent progress in addressing scientific questions on carbon-supported electrocatalysts through the development of advanced instruments and experimental methods.We then discuss the remaining challenges and potential research directions in nextgeneration materials frontiers,and suggest challenges and perspectives for shedding light on the structure–activity relationship.展开更多
Transition metal selenides have aroused great attention in recent years due to their high theoretical capacity.However,the huge volume fluctuation generated by conversion reaction during the charge/discharge process r...Transition metal selenides have aroused great attention in recent years due to their high theoretical capacity.However,the huge volume fluctuation generated by conversion reaction during the charge/discharge process results in the significant electrochemical performance reduction.Herein,the carbon-regulated copper(I)selenide(Cu_(2)Se@C)is designed to significantly promote the interface stability and ion diffusion for selenide electrodes.The systematic X-ray spectroscopies characterizations and density functional theory(DFT)simulations reveal that the Cu–Se–C bonding forming on the surface of Cu2Se not only improves the electronic conductivity of Cu_(2)Se@C but also retards the volume change during electrochemical cycling,playing a pivotal role in interface regulation.Consequently,the storage kinetics of Cu_(2)Se@C is mainly controlled by the capacitance process diverting from the ion diffusion-controlled process of Cu2Se.When employed this distinctive Cu_(2)Se@C as anode active material in Li coin cell configuration,the ultrahigh specific capacity of 810.3 mA·h·g^(−1)at 0.1 A·g^(−1)and the capacity retention of 83%after 1,500 cycles at 5 A·g^(−1)is achieved,implying the best Cu-based Li^(+)-storage capacity reported so far.This strategy of heterojunction combined with chemical bonding regulation opens up a potential way for the development of advanced electrodes for battery storage systems.展开更多
Metal-nitrogen-carbon materials are promising catalysts for CO2 electroreduction to CO. Herein, by taking the unique hierarchical carbon nanocages as the support, an advanced nickel-nitrogen-carbon single-site catalys...Metal-nitrogen-carbon materials are promising catalysts for CO2 electroreduction to CO. Herein, by taking the unique hierarchical carbon nanocages as the support, an advanced nickel-nitrogen-carbon single-site catalyst is conveniently prepared by pyrolyzing the mixture of NiCl2 and phenanthroline, which exhibits a Faradaic efficiency plateau of > 87% in a wide potential window of −0.6 – −1.0 V. Further S-doping by adding KSCN into the precursor much enhances the CO specific current density by 68%, up to 37.5 A·g−1 at −0.8 V, along with an improved CO Faradaic efficiency plateau of > 90%. Such an enhancement can be ascribed to the facilitated CO pathway and suppressed hydrogen evolution from thermodynamic viewpoint as well as the increased electroactive surface area and improved charge transfer fromkinetic viewpoint due to the S-doping. This study demonstrates a simple and effective approach to advanced electrocatalysts by synergetic modification of the porous carbon-based support and electronic structure of the active sites.展开更多
The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder pra...The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder practical applications such as electrolyzer compatible with the powerful proton exchange membrane and biohybrid fuel production.Here,we report a borondoped ruthenium dioxide electrocatalyst(B-RuO_(2))fabricated by a facile boric acid assisted strategy which demonstrates excellent acidic and neutral OER performances.Density functional theory calculations and advanced characterizations reveal that the boron species form an anomalous B–O covalent bonding with the oxygen atoms of RuO_(2)and expose the fully coordinately bridge ruthenium site(Ru-bri site),which seems like a switch that turns on the inactive Ru-bri site into OER-active,resulting in more exposed active sites,modified electronic structure,and optimized binding energy of intermediates.Thus,the B-RuO_(2)exhibits an ultralow overpotential of 200 mV at 10 mA/cm^(2)and maintains excellent stability compared to commercial RuO_(2)in 0.5 M sulfuric acid.Moreover,the superior performance is as well displayed in neutral electrolyte,surpassing most previously reported catalysts.展开更多
The phase transformation of catalysts has been extensively observed in heterogeneous catalytic reactions that hinder the long cycling catalysis,and it remains a big challenge to precisely control the active phase duri...The phase transformation of catalysts has been extensively observed in heterogeneous catalytic reactions that hinder the long cycling catalysis,and it remains a big challenge to precisely control the active phase during the complex conditions in electrochemical catalysis.Here,we theoretically predict that carbon-based support could achieve the phase engineering regulation of catalysts by suppressing specific phase transformation.Taken single-walled carbon nanotube(SWCNT)as typical support,combined with calculated E-pH(Pourbaix)diagram and advanced synchrotron-based characterizations technologies prove there are two different active phases source from cobalt selenide which demonstrate that the feasibility of using support effect regulating the potential advantageous catalysts.Moreover,it is worth noting that the phase engineering derived Co_(3)O_(4)-SWCNT exhibits a low overpotential of 201 mV for delivering the current density of 10 mA/cm^(2)in electrocatalytic oxygen evolution reaction(OER).Also,it reaches a record current density of 529 mA/cm^(2)at 1.63 V(vs.RHE)in the electrocatalytic urea oxidation reaction(UOR),overwhelming most previously reported catalysts.展开更多
基金the support from the high-performance computing platform of Jiangsu UniversityThe Jiangsu University Foundation (18JDG019)+3 种基金the Postdoctoral Foundation of Jiangsu Province (2018K072C)Six Talent Peak Project of Jiangsu Province (XLC-158)the China Postdoctoral Science Foundation (2019M651727, 2019M651719)the National Natural Science Foundation of China (21808090, 51902139, U1932211) financially supported this work。
文摘Hematite is regarded as a promising photoanode for photoelectrochemical(PEC) water splitting.However,the charge recombination occurred at the interface of FTO/hematite strictly limits the PEC performance of hematite.Herein,we reported a Ti3C2 MXene underlayer modified hematite(Ti-Fe2O3) photoanode via a simple drop-casting followed by hydrothermal and annealing processes.Owing to the bifunctional role of Ti3C2 MXene underlayer in improving the interfacial properties of FTO/hematite and providing Ti source for the construction of Fe2 TiO5/Fe2O3 heterostructure in hematite nanostructure,the bulk and interfacial charge transfer dynamics of hematite are significantly enhanced,and consequently enhancing the PEC performance.Compared with the pristine hematite,the as-prepared Ti-Fe2O3 photoanode shows an increased photocurrent density from 0.80 mA/cm^(2) to 1.30 mA/cm^(2) at 1.23 V vs.RHE.Moreover,a further promoted PEC performance including a dramatically increased photocurrent density of 2.49 mA/cm^(2) at1.23 V vs.RHE and an obviously lowered onset potential is achieved for the Ti-Fe2O3 sample after the subsequent surface F-treatment and the loading of FeNiOOH cocatalyst.Such results suggest that the introduction of Ti3C2 MXene underlayer is a facile but effective approach to improve the PEC water splitting activity of hematite.
基金financially supported by the National Key R&D Program of China (2019YFA0210000, 2021YFA1501502)the National Natural Science Foundation of China (22075263, 52002366, 12205303)the Fundamental Research Funds for the Central Universities (WK2060000039, WK2310000108)。
文摘MXene stands out as a rising family of transition metal carbides/nitrides with exceptional size-dependent properties and versatile potential applications. However, the realization of large MXene with a controllable surface at atomic level remains challenging to keep the balance among the conductivity, stability and activity. Herein, the horizontal oscillation-induced delamination(HOD)strategy is proposed to acquire Ti_(3)C_(2) flakes with large size and low Ti–Ti coordination(HO-Ti_(3)C_(2)). The average size of the asobtained flakes can reach 6.48 μm to keep the overall conductive skeleton and merits from large size. Simultaneously, metal atoms at surface can be partially removed due to the enhanced local vibrational turbulence during the reciprocating horizontal oscillation process. Such MXenes with clear and unique surface states exhibit high potentials in ion adsorption together with satisfied electric conductivity and stability. As proof of concept, HO-Ti_(3)C_(2) anode exhibits remarkable rate capability and longterm stability during sodium storage. A capacity of 100.5 m Ah g^(-1)with a long-life cycle(4,500 cycles) at a high rate of 1.0 A g^(-1)originates from the increased s-d interaction between Na and Ti. Therefore, the HOD strategy provides a controllable surface design to promote the clear criteria into size-dependent research on MXene.
基金supported in part by the National Key R&D Program of China(Nos.2020YFA0405800,2022YFA1504104,and 2022YFA1605400)the National Natural Science Foundation of China(Nos.12225508,12322515,U1932201,U2032113,and 22075264)+5 种基金the Youth Innovation Promotion Association of CAS(No.2022457)the Institute of Energy,Hefei Comprehensive National Science Center,University Synergy Innovation Program of Anhui Province(No.GXXT-2020-002)and the CAS Iterdisciplinary Innovation Team.We thank the Shanghai Synchrotron Radiation Facility(BL14W1,BL14B1,and SSRF)the Beijing Synchrotron Radiation Facility(1W1B,4B7A,and BSRF)the Hefei Synchrotron Radiation Facility(Infrared Spectroscopy and Microspectroscopy,MCD-A and MCD-B Soochow Beamline for Energy Materials at NSRL)and the USTC Center for Micro and Nanoscale Research and Fabrication for helps in characterizations.
文摘Breakthroughs in energy storage and conversion devices depend heavily on the exploration of low-cost and high-performance materials.Carbon-supported electrocatalysts with dimensional varieties have recently attracted significant attention due to their strong structural flexibility and easy accessibility.Nevertheless,understanding the connection between their electronic,structural properties,and catalytic performance must remain a top priority.Synchrotron radiation(SR)X-ray absorption spectroscopy(XAS)techniques,including hard XAS and soft XAS,are recognized as efficient and comprehensive platforms for probing the surface,interface,and bulk electronic structure of elements of interest in the materials community.In the past decade,the flourishing development of materials science and advanced characterization technologies have led to a deeper understanding at different temporal,longitudinal,and spatial scales.In this review,we briefly describe the concept of XAS techniques and summarize their recent progress in addressing scientific questions on carbon-supported electrocatalysts through the development of advanced instruments and experimental methods.We then discuss the remaining challenges and potential research directions in nextgeneration materials frontiers,and suggest challenges and perspectives for shedding light on the structure–activity relationship.
基金financially supported in part by the National Key Research and Development Program of China(No.2020YFA0405800)the National Natural Science Foundation of China(NSFC,Nos.U1932201 and U2032113)+4 种基金Youth Innovation Promotion Association of Chinese Academy of Sciences(CAS)(No.2022457)CAS Collaborative Innovation Program of Hefei Science Center(No.2020HSC-CIP002)CAS International Partnership Program(No.211134KYSB20190063)the Fundamental Research Funds for the Central Universities(No.WK2060000039)L.S.acknowledges the support from the Institute of Energy,Hefei Comprehensive National Science Center,University Synergy Innovation Program of Anhui Province(No.GXXT-2020-002).
文摘Transition metal selenides have aroused great attention in recent years due to their high theoretical capacity.However,the huge volume fluctuation generated by conversion reaction during the charge/discharge process results in the significant electrochemical performance reduction.Herein,the carbon-regulated copper(I)selenide(Cu_(2)Se@C)is designed to significantly promote the interface stability and ion diffusion for selenide electrodes.The systematic X-ray spectroscopies characterizations and density functional theory(DFT)simulations reveal that the Cu–Se–C bonding forming on the surface of Cu2Se not only improves the electronic conductivity of Cu_(2)Se@C but also retards the volume change during electrochemical cycling,playing a pivotal role in interface regulation.Consequently,the storage kinetics of Cu_(2)Se@C is mainly controlled by the capacitance process diverting from the ion diffusion-controlled process of Cu2Se.When employed this distinctive Cu_(2)Se@C as anode active material in Li coin cell configuration,the ultrahigh specific capacity of 810.3 mA·h·g^(−1)at 0.1 A·g^(−1)and the capacity retention of 83%after 1,500 cycles at 5 A·g^(−1)is achieved,implying the best Cu-based Li^(+)-storage capacity reported so far.This strategy of heterojunction combined with chemical bonding regulation opens up a potential way for the development of advanced electrodes for battery storage systems.
基金the National Key Research and Development Program of China(Nos.2017 YFA0206500 and 2018YFA0209103)the National Natural Science Foundation of China(Nos.21832003,21773111,21972061,51571110,and 21573107).The numerical calculations have been done on the computing facilities in the High Performance Computing Center(HPCC)of Nanjing University.
文摘Metal-nitrogen-carbon materials are promising catalysts for CO2 electroreduction to CO. Herein, by taking the unique hierarchical carbon nanocages as the support, an advanced nickel-nitrogen-carbon single-site catalyst is conveniently prepared by pyrolyzing the mixture of NiCl2 and phenanthroline, which exhibits a Faradaic efficiency plateau of > 87% in a wide potential window of −0.6 – −1.0 V. Further S-doping by adding KSCN into the precursor much enhances the CO specific current density by 68%, up to 37.5 A·g−1 at −0.8 V, along with an improved CO Faradaic efficiency plateau of > 90%. Such an enhancement can be ascribed to the facilitated CO pathway and suppressed hydrogen evolution from thermodynamic viewpoint as well as the increased electroactive surface area and improved charge transfer fromkinetic viewpoint due to the S-doping. This study demonstrates a simple and effective approach to advanced electrocatalysts by synergetic modification of the porous carbon-based support and electronic structure of the active sites.
基金the National Key Research and Development Program of China(No.2020YFA0405800)the National Natrual Science Foundation of China(Nos.U1932201,U2032113,and 22075264)+2 种基金CAS Collaborative Innovation Program of Hefei Science Center(No.2020HSC-CIP002)CAS Interdisciplinary Innovation Team,and USTC Research Funds of the Double First-Class Initiative(No.YD2310002003)L.S.also thanks the financial support from State Key Laboratory of Inorganic Synthesis and Preparative Chemistry,College of Chemistry,Jilin University.
文摘The electrocatalysis of oxygen evolution reaction(OER)plays a key role in clean energy storage and transfer.Nonetheless,the sluggish kinetics and poor durability under acidic and neutral conditions severely hinder practical applications such as electrolyzer compatible with the powerful proton exchange membrane and biohybrid fuel production.Here,we report a borondoped ruthenium dioxide electrocatalyst(B-RuO_(2))fabricated by a facile boric acid assisted strategy which demonstrates excellent acidic and neutral OER performances.Density functional theory calculations and advanced characterizations reveal that the boron species form an anomalous B–O covalent bonding with the oxygen atoms of RuO_(2)and expose the fully coordinately bridge ruthenium site(Ru-bri site),which seems like a switch that turns on the inactive Ru-bri site into OER-active,resulting in more exposed active sites,modified electronic structure,and optimized binding energy of intermediates.Thus,the B-RuO_(2)exhibits an ultralow overpotential of 200 mV at 10 mA/cm^(2)and maintains excellent stability compared to commercial RuO_(2)in 0.5 M sulfuric acid.Moreover,the superior performance is as well displayed in neutral electrolyte,surpassing most previously reported catalysts.
基金the National Key R&D Program of China(Nos.2020YFA0405800 and 2017YFA0303500)the National Natural Science Foundation of China(NSFC)(Nos.U1932201,U2032113,and 22075264)+3 种基金CAS Collaborative Innovation Program of Hefei Science Center(Nos.2019HSC-CIP002 and 2020HSC-CIP002)USTC Research Funds of the Double First-Class Initiative(No.YD2310002003)Institute of Energy,Hefei Comprehensive Nation Science Center,University Synergy Innovation Program of Anhui Province(GXXT-2020-002)CAS Iterdisciplinary Innovation Team.L.S.acknowledges the support from Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education),Nankai University(111 project,B12015)。
文摘The phase transformation of catalysts has been extensively observed in heterogeneous catalytic reactions that hinder the long cycling catalysis,and it remains a big challenge to precisely control the active phase during the complex conditions in electrochemical catalysis.Here,we theoretically predict that carbon-based support could achieve the phase engineering regulation of catalysts by suppressing specific phase transformation.Taken single-walled carbon nanotube(SWCNT)as typical support,combined with calculated E-pH(Pourbaix)diagram and advanced synchrotron-based characterizations technologies prove there are two different active phases source from cobalt selenide which demonstrate that the feasibility of using support effect regulating the potential advantageous catalysts.Moreover,it is worth noting that the phase engineering derived Co_(3)O_(4)-SWCNT exhibits a low overpotential of 201 mV for delivering the current density of 10 mA/cm^(2)in electrocatalytic oxygen evolution reaction(OER).Also,it reaches a record current density of 529 mA/cm^(2)at 1.63 V(vs.RHE)in the electrocatalytic urea oxidation reaction(UOR),overwhelming most previously reported catalysts.
