Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-dop...Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.展开更多
Hard carbon materials are characterized by having rich resources,simple processing technology,and low cost,and they are promising as one of the anode electrodes for commercial applications of sodium-/potassium-ion bat...Hard carbon materials are characterized by having rich resources,simple processing technology,and low cost,and they are promising as one of the anode electrodes for commercial applications of sodium-/potassium-ion batteries.Simultaneously,exploring the alkali metal ion storage mechanism is particularly important for designing high-performance electrode materials.However,the structure of hard carbon is more complex,and the description of energy storage behavior is quite controversial.In this study,the Magnolia grandiflora Lima leaf is used as a precursor,combined with simple pyrolysis and impurity removal processes,to obtain biomass-derived hard carbon material(carbonized Magnolia grandiflora Lima leaf[CMGL]).When it is used as an anode for sodium-ion batteries,it exhibits a high specific capacity of 315mAh/g,and the capacity retention rate is 90.0%after 100 cycles.For potassium-ion batteries,the charge specific capacity is 263.5mAh/g,with a capacity retention rate of 85.5%at the same cycling.Furthermore,different electrochemical analysis methods and microstructure characterization techniques were used to further elucidate the sodium/potassium storage mechanism of the material.All the results indicate that the high potential slope region represents the adsorption/desorption characteristics on the surface active sites,whereas the low-potential quasiplateau region belongs to the ion insertion/extraction in the graphitic microcrystallites interlayer.It is noteworthy that potassium ion is randomly intercalated between the graphitic microcrystallite layer without forming a segmented intercalation compound structure.展开更多
Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidati...Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidation removal of CO intermediates is crucial to the durability of EOR-based catalysts.Herein,in order to effectively avoiding the catalyst CO poisoning and improve the durability,the graphene-nickel nitride hybrids(AG-Ni_(3)N)were designed for supporting palladium nanoparticles(Pd/AG-Ni_(3)N)and then used for ethanol electrooxidation.The density functional theory(DFT)calculations demonstrated the introduction of AG-Ni_(3)N depresses the CO absorption and simultaneously promotes the adsorption of OH species for CO oxidation removal.The fabricated Pd/AG-Ni_(3)N catalyst distinctively exhibits excellent electroactivity with the mass catalytic activity of 3499.5 m A mg^(-1) on EOR in alkaline media,which is around 5.24 times higher than Pd/C(commercial catalyst).Notably,the Pd/AG-Ni_(3)N hybrids display excellent stability and durability after chronoamperometric measurements with a total operation time of 150,000 s.展开更多
Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-ind...Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-induced electric field(PIEF)with different directions,to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd.Tourmaline nanoparticles are applied as the PIEF provider,of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field.Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd,reduced adsorption energy of COad,enhanced adsorption energy of*HCOOH and*OH,and promoted formate pathway of formic acid electrooxidation.Pd/TNP+/FTO,with the aid of positive PIEF,shows three-fold enhancement in the formic acid electrooxidation(4.74 mA·cm^(−2))with high durability and anti-poisoning ability compared with pristine Pd.This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field.展开更多
Rechargeable non-aqueous Li-O2 battery is regarded as one of the most promising energy-storage technologies on account of its high energy density.It is believed that the rational design of three-dimensional (3D) archi...Rechargeable non-aqueous Li-O2 battery is regarded as one of the most promising energy-storage technologies on account of its high energy density.It is believed that the rational design of three-dimensional (3D) architecture for catalyst is a key factor for the remarkable performance.Metal-organic frameworks (MOFs) derived materials possess excellent architecture,which is beneficial for Li-O2 batteries.In this work,ZIF-67 is used as precursor template and calcinated under different temperature to produce Co3O4 crystals.When the anneal treatment is under 350℃,the derived Co3O4 nanocage holds the most complete skeleton,which provides better charge transfer ability as well as O2 and Li^+ diffusion.Meanwhile,the Co3O4 nanocage owns more oxygen vacancies,offering more active sites.With the synergistic effect of nanocage structure and active sites,the Co3O4 nanocage stably delivers a large specific capacity of 15,500 mAh·g^-1 as well as a long cycle-life of 132 cycles at limited discharge capacity of 1,000 mAh·g^-1 under discharge/charge current density of 0.5 A·g^-1.展开更多
Lithium metal, the ideal anode material for next-generation high-energy batteries, suffers from the severe safety problem of Li dendrites. Herein, we report a simple approach to effectively maintain the morphology of ...Lithium metal, the ideal anode material for next-generation high-energy batteries, suffers from the severe safety problem of Li dendrites. Herein, we report a simple approach to effectively maintain the morphology of Li-metal anode and enhance the cycling performance of Li batteries by surface coating of a porous polyvinylidene fluoride (PVDF) thin film. In symmetrical cells testing, the cells with the Li@PVDF electrode display stable cycling performance more than 1300 h (650 cycles) at the current density of 0.5 mA/cm^2 with a stripping/plating capacity of 0.5 mAh/cm^2. The results with full cells employing Li@PVDF anode and LiFePO_4 cathode show a good cycling ability with a capacity retention of 80.0% after 500 cycles at 4 C and an excellent rate capability with a high capacity of 78.4 mAh/g even at a high rate of 10 C.展开更多
Nanometer scale thin film material of PtPd alloy supported on glassy carbon (nm-PtPd/GC) was prepared by the electrochemical codeposition method under cyclic voltammetric conditions. STM patterns demonstrated that the...Nanometer scale thin film material of PtPd alloy supported on glassy carbon (nm-PtPd/GC) was prepared by the electrochemical codeposition method under cyclic voltammetric conditions. STM patterns demonstrated that the prepared thin films are composed of layered crystallites in elliptic form. Electrochemical in situ FTIRS studies explored the abnormal infrared effects (AIREs) of nm-PtPd/GC for CO adsorption, which are (i) the remarkable enhancement of IR absorption, (ii) the inversion of COad band direction, and (iii) notable increase in the full width at half maximum (FWHM) of COad bands. The results demonstrated also that the enhancement factor of IR absorption varies with the thickness of PtPd alloy film and has reached a maximum value of 38.3 under the experimental conditions.展开更多
This paper reports an overpotential-dependent shape evolution of gold nano-crystals （Au NCs） in a choline chloride-urea （ChCl-urea） based deep eutectic solvent （DES）. It was found that the growth overpotentials ...This paper reports an overpotential-dependent shape evolution of gold nano-crystals （Au NCs） in a choline chloride-urea （ChCl-urea） based deep eutectic solvent （DES）. It was found that the growth overpotentials play a key role in tuning the shape of Au NCs. The shape evolution of Au NCs successively from concave rhombic dodecahedra （RD） to concave cubes, octopods, cuboctahedral boxes, and finally, to hollow octahedra （OH） was achieved by carefully controlling the growth overpotentials in the range from -0.50 to -0.95 V （vs. Pt quasi-reference electrode）. In addition, the presence of urea was important in the shape evolution of Au NCs. The surface structure of the as-prepared Au NCs was comprehensively characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and electrochemical studies. It was demonstrated that the electrocatalytic activity of the as-prepared Au NCs for D-glucose electrooxidation was sensitively dependent on their morphologies. The results illustrated that the dehydrogenated glucose adsorbed on concave RD and concave cubic Au NCs was preferentially transformed to gluconolactone at low electrode potentials. Subsequent gluconolactone oxidation occurred favorably on octopods with {111}-truncated arms and hollow OH at high electrode potential. This study opens up a new approach to develop the surface-structure-controlled growth of Au NCs by combining DES with electrochemical techniques. In addition, it is significant for the tuning of the electrocatalytic properties of NCs.展开更多
CO adsorption on nanometer-thin layer of surface alloys of Pt-Ru and Pt-Pd prepared by electrochemical codeposition has been studied using in situ FTIR spectroscopy. Abnormal infrared effects (AIREs) that consist of t...CO adsorption on nanometer-thin layer of surface alloys of Pt-Ru and Pt-Pd prepared by electrochemical codeposition has been studied using in situ FTIR spectroscopy. Abnormal infrared effects (AIREs) that consist of the enhancement of IR absorption by adsorbed CO on different surface sites and the inversion of IR band direction have been observed on the thin-layer prepared. The results also demonstrate the considerable significance of Pt-Ru and Pt-Pd surface alloys in electrocatalysis applications.展开更多
An array of platinum microelectrodes was designed and fabricated. The adsorption of CO on such a Pt microelectrode (μ-Pt) was investigated by employing microscope in situ FTIR spectroscopy. A nanostructured film is f...An array of platinum microelectrodes was designed and fabricated. The adsorption of CO on such a Pt microelectrode (μ-Pt) was investigated by employing microscope in situ FTIR spectroscopy. A nanostructured film is formed at the surface of μ-Pt (denoted as μ-Pt(R)) when it has been subjected to a treatment of fast potential cycling. Abnormal infrared effects (AIREs) were observed in CO adsorption on the surface of μ-Pt(R), consisting of the inversion of the IR bipolar CO band and the extensively enhanced IR adsorption of COad species.展开更多
Biological reduction of O2 to H2O justifies a serious look at heme as a potential O2 reduction reaction(ORR) catalyst for low temperature fuel cells.In this study,a novel non-platinum electrocatalyst for ORR was prepa...Biological reduction of O2 to H2O justifies a serious look at heme as a potential O2 reduction reaction(ORR) catalyst for low temperature fuel cells.In this study,a novel non-platinum electrocatalyst for ORR was prepared through hemin,which is hydrochloride of heme,supported on Black Pearls 2000 carbon black(Hm-BP) pyrolyzed at 700-900℃ in Ar atmosphere.The physical and electrocatalytic properties of as-prepared catalysts were characterized by TGA,XRD,XPS,TEM,rotating disk electrode(RDE) and rotating ring disk electrode(RRDE).It has found that the catalyst treated at 750℃(Hm-BP-750) exhibits the best property among the Hm-BP catalysts prepared.The onset potential of ORR on the Hm-BP-750 at 30℃ was measured ca.0.90 V(vs.RHE) in 0.1 M H2SO4,and mass current density was reached 15.3 mA mg-1 at 0.75 V.It has revealed that O2 could be reduced directly to water in a 4e process between 0.9 and 0.83V,and the yield of H2O2 was 0-18% in the potential range of 0.83-0.63 V.This methanol-tolerant catalyst also presents excellent stability in medium-term test of direct methanol fuel cell at 80℃.展开更多
Designing bifunctional oxygen electrocatalysts with high activity,lasting stability,and low-cost for rechargeable zinc-air batteries(RZABs)is a tough challenge.Herein,an advanced electrocatalyst is prepared by anchori...Designing bifunctional oxygen electrocatalysts with high activity,lasting stability,and low-cost for rechargeable zinc-air batteries(RZABs)is a tough challenge.Herein,an advanced electrocatalyst is prepared by anchoring atomically dispersed Co atoms on Ndoped graphene-like hierarchically porous carbon nanosheets(SA-Co-N4-GCs)and thereby forming Co-N4-C architecture.Its unique structure with excellent conductivity,large surface area,and three dimensional(3D)interconnected hierarchically porous architecture exposes not only more Co-N4 active sites to accelerate the kinetics of both oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),but also provides an efficient charge/mass transport environment to reduce diffusion barrier.Consequently,SA-Co-N4-GCs exhibits excellent ORR/OER bifunctional activities and durability,surpassing noble-metal catalysts.Liquid RZABs using SA-Co-N4-GCs cathodes display a high open-circuit voltage of 1.51 V,a remarkable power density of 149.3 mW·cm−2,as well as excellent stability and rechargeability with faint increase in polarization even at a large depth of charge–discharge cycle with 16 h per cycle over an entire 600 h long-term test.Moreover,flexible quasi-solid-state RZABs with SA-Co-N4-GCs cathodes also deliver a considerable power density of 124.5 mW·cm−2,which is even higher than that of liquid batteries using noble-metal catalysts.This work has thrown new insight into development of high-performance and low-cost electrocatalysts for energy conversion and storage.展开更多
基金financially supported by the National Natural Science Foundation of China (22005097)the State Key Laboratory of Physical Chemistry of Solid Surfaces,Xiamen University,Xiamen 361005,P.R.China (201815)。
文摘Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.
基金This study was financially supported by the National Natural Science Foundation of China(No.21965017).
文摘Hard carbon materials are characterized by having rich resources,simple processing technology,and low cost,and they are promising as one of the anode electrodes for commercial applications of sodium-/potassium-ion batteries.Simultaneously,exploring the alkali metal ion storage mechanism is particularly important for designing high-performance electrode materials.However,the structure of hard carbon is more complex,and the description of energy storage behavior is quite controversial.In this study,the Magnolia grandiflora Lima leaf is used as a precursor,combined with simple pyrolysis and impurity removal processes,to obtain biomass-derived hard carbon material(carbonized Magnolia grandiflora Lima leaf[CMGL]).When it is used as an anode for sodium-ion batteries,it exhibits a high specific capacity of 315mAh/g,and the capacity retention rate is 90.0%after 100 cycles.For potassium-ion batteries,the charge specific capacity is 263.5mAh/g,with a capacity retention rate of 85.5%at the same cycling.Furthermore,different electrochemical analysis methods and microstructure characterization techniques were used to further elucidate the sodium/potassium storage mechanism of the material.All the results indicate that the high potential slope region represents the adsorption/desorption characteristics on the surface active sites,whereas the low-potential quasiplateau region belongs to the ion insertion/extraction in the graphitic microcrystallites interlayer.It is noteworthy that potassium ion is randomly intercalated between the graphitic microcrystallite layer without forming a segmented intercalation compound structure.
基金funded by the National Natural Science Foundation of China(No.91745112)sponsored by Shanghai Rising-Star Program(No.19QA1404100)+1 种基金Financial support from the Science and Technology Commission of Shanghai Municipality(Nos.19DZ2271100 and 18020500800)the support from the Opening Project of PCOSS,Xiamen University,201910。
文摘Electrocatalysts for ethanol oxidation reaction(EOR)are generally limited by their poor durability because of the catalyst poisoning induced by the reaction intermediate carbon monoxide(CO).Therefore,the rapid oxidation removal of CO intermediates is crucial to the durability of EOR-based catalysts.Herein,in order to effectively avoiding the catalyst CO poisoning and improve the durability,the graphene-nickel nitride hybrids(AG-Ni_(3)N)were designed for supporting palladium nanoparticles(Pd/AG-Ni_(3)N)and then used for ethanol electrooxidation.The density functional theory(DFT)calculations demonstrated the introduction of AG-Ni_(3)N depresses the CO absorption and simultaneously promotes the adsorption of OH species for CO oxidation removal.The fabricated Pd/AG-Ni_(3)N catalyst distinctively exhibits excellent electroactivity with the mass catalytic activity of 3499.5 m A mg^(-1) on EOR in alkaline media,which is around 5.24 times higher than Pd/C(commercial catalyst).Notably,the Pd/AG-Ni_(3)N hybrids display excellent stability and durability after chronoamperometric measurements with a total operation time of 150,000 s.
基金This work was financially supported by the National Natural Science Foundation of China(No.22005097).
文摘Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-induced electric field(PIEF)with different directions,to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd.Tourmaline nanoparticles are applied as the PIEF provider,of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field.Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd,reduced adsorption energy of COad,enhanced adsorption energy of*HCOOH and*OH,and promoted formate pathway of formic acid electrooxidation.Pd/TNP+/FTO,with the aid of positive PIEF,shows three-fold enhancement in the formic acid electrooxidation(4.74 mA·cm^(−2))with high durability and anti-poisoning ability compared with pristine Pd.This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field.
基金the National Key R&D Program of China (No.2016YFB0100200)Science Foundation of China University of Petroleum,Beijing (C201604,No.2462014YJRC003)State key laboratory of physical chemistry of solid surfaces,Xiamen University (No.201703).
文摘Rechargeable non-aqueous Li-O2 battery is regarded as one of the most promising energy-storage technologies on account of its high energy density.It is believed that the rational design of three-dimensional (3D) architecture for catalyst is a key factor for the remarkable performance.Metal-organic frameworks (MOFs) derived materials possess excellent architecture,which is beneficial for Li-O2 batteries.In this work,ZIF-67 is used as precursor template and calcinated under different temperature to produce Co3O4 crystals.When the anneal treatment is under 350℃,the derived Co3O4 nanocage holds the most complete skeleton,which provides better charge transfer ability as well as O2 and Li^+ diffusion.Meanwhile,the Co3O4 nanocage owns more oxygen vacancies,offering more active sites.With the synergistic effect of nanocage structure and active sites,the Co3O4 nanocage stably delivers a large specific capacity of 15,500 mAh·g^-1 as well as a long cycle-life of 132 cycles at limited discharge capacity of 1,000 mAh·g^-1 under discharge/charge current density of 0.5 A·g^-1.
基金supported by the National Natural Science Foundation of China(Nos. 21621091, 21273184)the National Key Research and Development Program of China(No. 2016YFB0100202)
文摘Lithium metal, the ideal anode material for next-generation high-energy batteries, suffers from the severe safety problem of Li dendrites. Herein, we report a simple approach to effectively maintain the morphology of Li-metal anode and enhance the cycling performance of Li batteries by surface coating of a porous polyvinylidene fluoride (PVDF) thin film. In symmetrical cells testing, the cells with the Li@PVDF electrode display stable cycling performance more than 1300 h (650 cycles) at the current density of 0.5 mA/cm^2 with a stripping/plating capacity of 0.5 mAh/cm^2. The results with full cells employing Li@PVDF anode and LiFePO_4 cathode show a good cycling ability with a capacity retention of 80.0% after 500 cycles at 4 C and an excellent rate capability with a high capacity of 78.4 mAh/g even at a high rate of 10 C.
基金the National Naturalscience Foundation of China (Grant Nos. 29833060 and 29525307) and the Ministry of Education of China (Grant Nos. 1999038403 and 99177).
文摘Nanometer scale thin film material of PtPd alloy supported on glassy carbon (nm-PtPd/GC) was prepared by the electrochemical codeposition method under cyclic voltammetric conditions. STM patterns demonstrated that the prepared thin films are composed of layered crystallites in elliptic form. Electrochemical in situ FTIRS studies explored the abnormal infrared effects (AIREs) of nm-PtPd/GC for CO adsorption, which are (i) the remarkable enhancement of IR absorption, (ii) the inversion of COad band direction, and (iii) notable increase in the full width at half maximum (FWHM) of COad bands. The results demonstrated also that the enhancement factor of IR absorption varies with the thickness of PtPd alloy film and has reached a maximum value of 38.3 under the experimental conditions.
基金supported by the National Natural Science Foundation of China (21875042)Shanghai Science and Technology Committee (18QA1400800)+1 种基金the Program of Eastern Scholar at Shanghai Institutions and Yanchang Petroleum Groupsupported by the Frontier Research Center for Materials Structure, School of Materials Science and Engineering of Shanghai Jiao Tong University
基金This study was supported financially by the National Natural Science Foundation of China （Nos. 21361140374, 21229301, 21378113, and 21573183） and the Natural Science Fund project in Jiangsu Province, China （No. BK20160210）.
文摘This paper reports an overpotential-dependent shape evolution of gold nano-crystals （Au NCs） in a choline chloride-urea （ChCl-urea） based deep eutectic solvent （DES）. It was found that the growth overpotentials play a key role in tuning the shape of Au NCs. The shape evolution of Au NCs successively from concave rhombic dodecahedra （RD） to concave cubes, octopods, cuboctahedral boxes, and finally, to hollow octahedra （OH） was achieved by carefully controlling the growth overpotentials in the range from -0.50 to -0.95 V （vs. Pt quasi-reference electrode）. In addition, the presence of urea was important in the shape evolution of Au NCs. The surface structure of the as-prepared Au NCs was comprehensively characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and electrochemical studies. It was demonstrated that the electrocatalytic activity of the as-prepared Au NCs for D-glucose electrooxidation was sensitively dependent on their morphologies. The results illustrated that the dehydrogenated glucose adsorbed on concave RD and concave cubic Au NCs was preferentially transformed to gluconolactone at low electrode potentials. Subsequent gluconolactone oxidation occurred favorably on octopods with {111}-truncated arms and hollow OH at high electrode potential. This study opens up a new approach to develop the surface-structure-controlled growth of Au NCs by combining DES with electrochemical techniques. In addition, it is significant for the tuning of the electrocatalytic properties of NCs.
文摘CO adsorption on nanometer-thin layer of surface alloys of Pt-Ru and Pt-Pd prepared by electrochemical codeposition has been studied using in situ FTIR spectroscopy. Abnormal infrared effects (AIREs) that consist of the enhancement of IR absorption by adsorbed CO on different surface sites and the inversion of IR band direction have been observed on the thin-layer prepared. The results also demonstrate the considerable significance of Pt-Ru and Pt-Pd surface alloys in electrocatalysis applications.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 29525307 and 29833060) and the Ministry of Education of China (Grant No. 1999038403).
文摘An array of platinum microelectrodes was designed and fabricated. The adsorption of CO on such a Pt microelectrode (μ-Pt) was investigated by employing microscope in situ FTIR spectroscopy. A nanostructured film is formed at the surface of μ-Pt (denoted as μ-Pt(R)) when it has been subjected to a treatment of fast potential cycling. Abnormal infrared effects (AIREs) were observed in CO adsorption on the surface of μ-Pt(R), consisting of the inversion of the IR bipolar CO band and the extensively enhanced IR adsorption of COad species.
基金supported by the National Natural Science Foundation of China (20933004, 20833005, and 20921120405)
文摘Biological reduction of O2 to H2O justifies a serious look at heme as a potential O2 reduction reaction(ORR) catalyst for low temperature fuel cells.In this study,a novel non-platinum electrocatalyst for ORR was prepared through hemin,which is hydrochloride of heme,supported on Black Pearls 2000 carbon black(Hm-BP) pyrolyzed at 700-900℃ in Ar atmosphere.The physical and electrocatalytic properties of as-prepared catalysts were characterized by TGA,XRD,XPS,TEM,rotating disk electrode(RDE) and rotating ring disk electrode(RRDE).It has found that the catalyst treated at 750℃(Hm-BP-750) exhibits the best property among the Hm-BP catalysts prepared.The onset potential of ORR on the Hm-BP-750 at 30℃ was measured ca.0.90 V(vs.RHE) in 0.1 M H2SO4,and mass current density was reached 15.3 mA mg-1 at 0.75 V.It has revealed that O2 could be reduced directly to water in a 4e process between 0.9 and 0.83V,and the yield of H2O2 was 0-18% in the potential range of 0.83-0.63 V.This methanol-tolerant catalyst also presents excellent stability in medium-term test of direct methanol fuel cell at 80℃.
基金the National Natural Science Foundation of China(Nos.21603103 and U1601214)the Natural Science Foundation Committee of Jiangsu Province(No.BK20171462)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX21_0465).
文摘Designing bifunctional oxygen electrocatalysts with high activity,lasting stability,and low-cost for rechargeable zinc-air batteries(RZABs)is a tough challenge.Herein,an advanced electrocatalyst is prepared by anchoring atomically dispersed Co atoms on Ndoped graphene-like hierarchically porous carbon nanosheets(SA-Co-N4-GCs)and thereby forming Co-N4-C architecture.Its unique structure with excellent conductivity,large surface area,and three dimensional(3D)interconnected hierarchically porous architecture exposes not only more Co-N4 active sites to accelerate the kinetics of both oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),but also provides an efficient charge/mass transport environment to reduce diffusion barrier.Consequently,SA-Co-N4-GCs exhibits excellent ORR/OER bifunctional activities and durability,surpassing noble-metal catalysts.Liquid RZABs using SA-Co-N4-GCs cathodes display a high open-circuit voltage of 1.51 V,a remarkable power density of 149.3 mW·cm−2,as well as excellent stability and rechargeability with faint increase in polarization even at a large depth of charge–discharge cycle with 16 h per cycle over an entire 600 h long-term test.Moreover,flexible quasi-solid-state RZABs with SA-Co-N4-GCs cathodes also deliver a considerable power density of 124.5 mW·cm−2,which is even higher than that of liquid batteries using noble-metal catalysts.This work has thrown new insight into development of high-performance and low-cost electrocatalysts for energy conversion and storage.
