Photo-thermal CO_(2) reduction with methane(CRM)is beneficial for solar energy harvesting and energy storage.The search for efficient photo-thermal catalysts is of great significance.Here,we reveal that group Ⅷ metal...Photo-thermal CO_(2) reduction with methane(CRM)is beneficial for solar energy harvesting and energy storage.The search for efficient photo-thermal catalysts is of great significance.Here,we reveal that group Ⅷ metal catalysts supported by optical material WO_(3) are more effective for photo-thermal CRM,giving catalytic activities with visible light assistance that are 1.4-2.4 times higher than that achieved under thermal conditions.The activity enhancement(1.4-2.4 times)was comparable to that achieved with plasmonic-Au-promoted catalysts(1.7 times).Characterization results indicated that WO_(3) was partially reduced to WO_(3-x) in situ under the reductive CRM reaction atmosphere,and that WO_(3-x) rather than WO_(3) enhanced the activities with visible light assistance.Our method provides a promising approach for improving the activity of catalysts under light irradiation.展开更多
This article reports the production of COx free hydrogen and carbon nanofibers by the catalytic decomposition of methane over Ni-Al2O3-SiO2 catalysts. The influence of reaction temperature, pretreatment temperature, a...This article reports the production of COx free hydrogen and carbon nanofibers by the catalytic decomposition of methane over Ni-Al2O3-SiO2 catalysts. The influence of reaction temperature, pretreatment temperature, and effect of reductive pretreatment on the decomposition of methane activity is investigated. The physico-chemical characteristics of fresh and deactivated samples were characterized using BET-SA, XRD, TPR, SEM/TEM, CHNS analyses and correlated with the methane decomposition results obtained. The Ni-Al-Si （4 ： 0.5 ： 1.5） catalyst reduced with hydrazine hydrate produced better H2 yields of ca. 1815 mol H2/mol Ni than the catalyst reduced with 5% H2/N2.展开更多
Biofilm is an effective simultaneous denitrification and in situ sludge reduction system,and the characteristics of different biofilm carrier have important implications for biofilm growth and in situ sludge reduction...Biofilm is an effective simultaneous denitrification and in situ sludge reduction system,and the characteristics of different biofilm carrier have important implications for biofilm growth and in situ sludge reduction.In this study,the performance and mechanism of in situ sludge reduction were compared between FSC-SBBR and SC-SBBR with constructed by composite floating spherical carriers(FSC)and multi-faceted polyethylene suspension carriers(SC),respectively.The variation of EPS concentration indicated that the biofilm formation of FSC was faster than SC.Compared with SCSBBR,the FSC-SBBR yielded 0.16 g MLSS/g COD,almost 27.27%less sludge.The average removal rates of COD and NH_(4)^(+)-N were 93.39% and 96.66%,respectively,which were 5.21% and 1.43% higher than the average removal rate of SC-SBBR.Investigation of the mechanisms of sludge reduction revealed that,energy uncoupling metabolism and sludge decay were the main factors for sludge reduction inducing 43.13%and 49.65%less sludge,respectively,in FSC-SBBR.EEM fluorescence spectroscopy and SUVA analysis showed that the hydrolytic capacity of biofilm attached in FSC was stronger than those of SC,and the hydrolysis of EPS released more DOM contributed to lysis-cryptic growth metabolism.In additional,Bacteroidetes and Mizugakiibacter associated with sludge reduction were the dominant phylum and genus in FCS-SBBR.Thus,the effect of simultaneous in situ sludge reduction and pollutant removal in FSC-SBBR was better.展开更多
Silicon is considered an exceptionally promising alternative to the most commonly used material, graphite, as an anode for next-generation lithium-ion batteries, as it has high energy density owing to its high theoret...Silicon is considered an exceptionally promising alternative to the most commonly used material, graphite, as an anode for next-generation lithium-ion batteries, as it has high energy density owing to its high theoretical capacity and abundant storage. Here, microsized walnut-like porous silicon/reduced graphene oxide （P-Si/rGO） core-shell composites are successfully prepared via in situ reduction followed by a dealloying process. The composites show specific capacities of more than 2,100 mAh-g-1 at a current density of 1,000 mA-g-1, 1,600 mAh.g-1 at 2,000 mA-g-1, 1,500 mAh-g 1 at 3,000 mA-g-1, 1,200 mAh-g-1 at 4,000 mA.g-1, and 950 mAh.g~ at 5,000 mA.g-~, and maintain a value of 1,258 mAh.g-~ after 300 cycles at a current density of 1,000 mA-g 1. Their excellent rate performance and cycling stability can be attributed to the unique structural design： 1） The graphene shell dramatically improves the conductivity and stabilizes the solid- electrolyte interface layers; 2） the inner porous structure supplies sufficient space for silicon expansion; 3） the nanostructure of silicon can prevent the pulverization resulting from volume expansion stress. Notably, this in situ reduction method can be applied as a universal formula to coat graphene on almost all types of metals and alloys of various sizes, shapes, and compositions without adding any reagents to afford energy storage materials, graphene-based catalytic materials, graphene-enhanced composites, etc.展开更多
The heterostructure Ag@WO3-x（x=0.1 or 1） composites with high selectivity for breaking azo-bond were obtained by in situ reduction of Ag2WO4. The crystal structure and morphology of Ag@WO3-x were characterized by X-...The heterostructure Ag@WO3-x（x=0.1 or 1） composites with high selectivity for breaking azo-bond were obtained by in situ reduction of Ag2WO4. The crystal structure and morphology of Ag@WO3-x were characterized by X-ray powder diffraction（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The residue solution of methyl orange（MO） after degradation was tested by gas chromatograph mass spectrometer （GCMS） to analyze the exact components. The results indicate that the products after degradation are N,N-dimethylaniline, N,N-dimethyl-p-phenylenediamine and sulfanilic acid. This is caused by specific breaking of azo-bond in MO. The azo-bond breaking of MO by Ag@WO3-x could occur in dark without any light illumination. Therefore, we proposed a possible mechanism for this azo-bond breaking reaction based on the reaction condition and results.展开更多
The development of efficient and robust non-Pt and low-Pt catalysts with equivalent or even superior performance to commercial Pt-based catalysts for hydrogen evolution reaction(HER)is highly desired,but challenging,i...The development of efficient and robust non-Pt and low-Pt catalysts with equivalent or even superior performance to commercial Pt-based catalysts for hydrogen evolution reaction(HER)is highly desired,but challenging,in the field of water electrolysis.Herein,we report a facile and cost-effective in situ electrochemical approach for the synthesis of atomically dispersed metal sites including platinum(Pt),ruthenium(Ru),and palladium(Pd)on the polyaniline(PANI)support.The PANI exhibits not only high electrochemical conductivity but also efficientH+capture fromhydronium ions,leading to the formation of protonated amine groups that can be easily electrochemically reduced to H2 on atomically dispersed metal active sites.As an example,the atomically dispersed Pt sites anchored on carbon cloth-supported PANI(PANI-Pt/CC)demonstrate excellent activity and durability toward the HER.The mass activity of PANI-Pt-10/CC reaches 25 A mg_(Pt)^(−1),exhibiting a significant enhancement of 50-fold compared to that of the commercial Pt/C(0.5 A mg_(Pt)^(−1)).Therefore,this study presents a universally applicable approach for the design of atomically dispersed metal sites/conducting polymer heterostructures for highly efficient catalysts toward HER and beyond.展开更多
The sluggish reaction kinetics of CO_(2)electroreduction in perovskite-based cathodes severely limits the efficiency of solid oxide electrolysis cells(SOECs).The construction of the high-density active sites on the pe...The sluggish reaction kinetics of CO_(2)electroreduction in perovskite-based cathodes severely limits the efficiency of solid oxide electrolysis cells(SOECs).The construction of the high-density active sites on the perovskite sur-face is crucial for promoting CO_(2)electrolysis in SOEC.In this study,we explore a redox-induced redispersion strategy to produce RhO_(x)nanoclusters uniformly anchored on a Sr_(2)Fe_(1.45)Rh_(0.05)Mo_(0.5)O_(6-δ)(SFRhM)perovskite surface with a high density of 36,000μm^(−2).Compared with non-uniformly distributed RhO_(x)nanoparticles on Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)(RhO_(x)/SFM)prepared by a conventional impregnation process,the successive reduction and oxidation treatment first exsolves the highly dispersed RhFe alloy nanoparticles on SFRhM and then selectively dissolves the iron species in the RhFe alloy nanoparticles into the bulk of SFRhM,resulting in fully exposed RhO_(x)nanoclusters uniformly anchored on the SFRhM surface(RhO_(x)@SFRhM).Electrochemical measurements and density functional theory calculations indicate that the high-density RhO_(x)@SFRhM interfaces promote CO_(2)adsorption and activation during CO_(2)electrolysis,thus leading to improved electrocatalytic activity and stability compared to that of its SFRhM and RhO_(x)/SFM counterparts.展开更多
A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomat...A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH4 oxidation in alkaline solution. The morphology and phase composition of PtCo/C0304 NSs are characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy （XPS）. The catalytic performance of PtCo/Co3O4 NSs is investigated by cyclic voltammetry （CV） and chronoamperometry （CA） in a standard three-electrode system. Current densities of 70 and 850 mA·cm^-2 were obtained at -0.4 V for Co/Co3O4 and PtCo/Co3O4 NSs, respectively, in a solution containing 2 mol·L^-1 NaOH and 0.2 mol·L^-1 NaBH4. The use of a noble metal （Pt） greatly enhances the catalytic activity of the transition metal （Co） and Co3O4. Besides, both Co and Co3O4 exhibit good B-H bond breaking ability （in NaBH4）, which leads to better electrocatalytic activity and stability of PtCo/Co3O4 NSs in NaBH4 electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co3O4 NSs can be a promising electrocatalyst for borohydride oxidation.展开更多
结合了三维结构和亲锌物种的集流体构筑策略被认为是构建高稳定锌金属负极的有效方法.然而,高昂的成本和复杂的制备工艺阻碍了其实际应用.本文通过在有均匀Cu^(2+)锚定的碳布集流体(ACC-600@Cu^(2+))上沉积锌,合理设计了一种稳定的三维...结合了三维结构和亲锌物种的集流体构筑策略被认为是构建高稳定锌金属负极的有效方法.然而,高昂的成本和复杂的制备工艺阻碍了其实际应用.本文通过在有均匀Cu^(2+)锚定的碳布集流体(ACC-600@Cu^(2+))上沉积锌,合理设计了一种稳定的三维锌金属复合阳极(Zn@ACC-600@Cu^(2+)).在锌成核过程中,Cu^(2+)原位还原为金属Cu,然后随着锌的进一步沉积,碳布表面逐渐形成均匀的亲锌的Cu-Zn合金界面层.密度泛函理论计算和实验观察表明,Cu-Zn合金界面不仅可以作为锌离子的亲锌沉积点,而且可以提高导电率,使电场和锌离子通量均匀化.因此,ACC-600@Cu^(2+)集流体可以实现高的镀锌/剥离可逆性,并在15.8 mV的极化电压下稳定循环410 h以上.作为概念验证,我们组装的Zn@ACC-600@Cu^(2+)‖MnO_(2)全电池具有良好的电池倍率性能,与原始碳布相比,其比容量显著提高至110 mA h g^(-1).本文提出的原位还原策略为三维锌金属复合负极的设计提供了一种简便且低成本的方法,促进了无枝晶和高稳定锌金属电池的发展.展开更多
Reduced graphene oxide(rGO)films suffer from low capacitance for inner unreduced oxygen functional groups,restacking of sheets and high contact resistance.Herein,carbon spheres derived from renewable xylan were added ...Reduced graphene oxide(rGO)films suffer from low capacitance for inner unreduced oxygen functional groups,restacking of sheets and high contact resistance.Herein,carbon spheres derived from renewable xylan were added to graphene oxide with large sheet area to fabricate film by gelation and filtration,followed by in situ reduction for high-performance flexible supercapacitor.rGO film with transverse size about 13 pm showed a good specific capacitance of 967 mF/cm^(2) at a scanning rate of 5 mV/sand increased to 1786 mF/cm^(2) by in situ reducing its inner part,which generally remained oxidized due to outer hindering from hydrophobic graphene.Then,by hydrothermal carbonization of xylan and activation with KOH,activated carbon sphere(aXCS)was prepared,which had a diameter of 150-200 nm and a specific capacitance of 270 F/g.The aXCS acted as spacer and connector to avoid restacking of graphene sheets and decrease interlayer contact resistance,resulting 94%increase in capacitance performance from rGO film to aXCS/rGO film.Therefore,combined in situ reduction and enhancement through compositing aXCS,the final film(aXCS/rGO-AA)showed a boosted specific capacitance of 755 mF/cm^(2) at 1 mA/cm^(2) in double electrode system,power density of 22.5-2250 mW/cm^(2),and energy density of 11.88-25.2 mWh/cm^(2).Meanwhile,aXCS/rGO-AA had outstanding cycling stability that its specific capacitance maintained 108.7%after 10,000 cycles of charge-dis-charge,showing promising potential in wearable and portable electronics.展开更多
文摘Photo-thermal CO_(2) reduction with methane(CRM)is beneficial for solar energy harvesting and energy storage.The search for efficient photo-thermal catalysts is of great significance.Here,we reveal that group Ⅷ metal catalysts supported by optical material WO_(3) are more effective for photo-thermal CRM,giving catalytic activities with visible light assistance that are 1.4-2.4 times higher than that achieved under thermal conditions.The activity enhancement(1.4-2.4 times)was comparable to that achieved with plasmonic-Au-promoted catalysts(1.7 times).Characterization results indicated that WO_(3) was partially reduced to WO_(3-x) in situ under the reductive CRM reaction atmosphere,and that WO_(3-x) rather than WO_(3) enhanced the activities with visible light assistance.Our method provides a promising approach for improving the activity of catalysts under light irradiation.
文摘This article reports the production of COx free hydrogen and carbon nanofibers by the catalytic decomposition of methane over Ni-Al2O3-SiO2 catalysts. The influence of reaction temperature, pretreatment temperature, and effect of reductive pretreatment on the decomposition of methane activity is investigated. The physico-chemical characteristics of fresh and deactivated samples were characterized using BET-SA, XRD, TPR, SEM/TEM, CHNS analyses and correlated with the methane decomposition results obtained. The Ni-Al-Si （4 ： 0.5 ： 1.5） catalyst reduced with hydrazine hydrate produced better H2 yields of ca. 1815 mol H2/mol Ni than the catalyst reduced with 5% H2/N2.
基金supported by the Natural Science Foundation of Shandong Province(ZR2016EEM32)the Doctoral Fund of Shandong Jianzhu University in 2015(XNBS1511)Scientific and technological Innovation Project of Planning and Design Institute of Huaihe River Basin Water Conservancy Administration Bureau of Shandong Province in 2018(SFSJKY2018-01).
文摘Biofilm is an effective simultaneous denitrification and in situ sludge reduction system,and the characteristics of different biofilm carrier have important implications for biofilm growth and in situ sludge reduction.In this study,the performance and mechanism of in situ sludge reduction were compared between FSC-SBBR and SC-SBBR with constructed by composite floating spherical carriers(FSC)and multi-faceted polyethylene suspension carriers(SC),respectively.The variation of EPS concentration indicated that the biofilm formation of FSC was faster than SC.Compared with SCSBBR,the FSC-SBBR yielded 0.16 g MLSS/g COD,almost 27.27%less sludge.The average removal rates of COD and NH_(4)^(+)-N were 93.39% and 96.66%,respectively,which were 5.21% and 1.43% higher than the average removal rate of SC-SBBR.Investigation of the mechanisms of sludge reduction revealed that,energy uncoupling metabolism and sludge decay were the main factors for sludge reduction inducing 43.13%and 49.65%less sludge,respectively,in FSC-SBBR.EEM fluorescence spectroscopy and SUVA analysis showed that the hydrolytic capacity of biofilm attached in FSC was stronger than those of SC,and the hydrolysis of EPS released more DOM contributed to lysis-cryptic growth metabolism.In additional,Bacteroidetes and Mizugakiibacter associated with sludge reduction were the dominant phylum and genus in FCS-SBBR.Thus,the effect of simultaneous in situ sludge reduction and pollutant removal in FSC-SBBR was better.
文摘Silicon is considered an exceptionally promising alternative to the most commonly used material, graphite, as an anode for next-generation lithium-ion batteries, as it has high energy density owing to its high theoretical capacity and abundant storage. Here, microsized walnut-like porous silicon/reduced graphene oxide （P-Si/rGO） core-shell composites are successfully prepared via in situ reduction followed by a dealloying process. The composites show specific capacities of more than 2,100 mAh-g-1 at a current density of 1,000 mA-g-1, 1,600 mAh.g-1 at 2,000 mA-g-1, 1,500 mAh-g 1 at 3,000 mA-g-1, 1,200 mAh-g-1 at 4,000 mA.g-1, and 950 mAh.g~ at 5,000 mA.g-~, and maintain a value of 1,258 mAh.g-~ after 300 cycles at a current density of 1,000 mA-g 1. Their excellent rate performance and cycling stability can be attributed to the unique structural design： 1） The graphene shell dramatically improves the conductivity and stabilizes the solid- electrolyte interface layers; 2） the inner porous structure supplies sufficient space for silicon expansion; 3） the nanostructure of silicon can prevent the pulverization resulting from volume expansion stress. Notably, this in situ reduction method can be applied as a universal formula to coat graphene on almost all types of metals and alloys of various sizes, shapes, and compositions without adding any reagents to afford energy storage materials, graphene-based catalytic materials, graphene-enhanced composites, etc.
基金Supported by the National Natural Science Foundation of China（No.21371066）.
文摘The heterostructure Ag@WO3-x（x=0.1 or 1） composites with high selectivity for breaking azo-bond were obtained by in situ reduction of Ag2WO4. The crystal structure and morphology of Ag@WO3-x were characterized by X-ray powder diffraction（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The residue solution of methyl orange（MO） after degradation was tested by gas chromatograph mass spectrometer （GCMS） to analyze the exact components. The results indicate that the products after degradation are N,N-dimethylaniline, N,N-dimethyl-p-phenylenediamine and sulfanilic acid. This is caused by specific breaking of azo-bond in MO. The azo-bond breaking of MO by Ag@WO3-x could occur in dark without any light illumination. Therefore, we proposed a possible mechanism for this azo-bond breaking reaction based on the reaction condition and results.
基金The Natural Sciences and Engineering Research Council of Canada。
文摘The development of efficient and robust non-Pt and low-Pt catalysts with equivalent or even superior performance to commercial Pt-based catalysts for hydrogen evolution reaction(HER)is highly desired,but challenging,in the field of water electrolysis.Herein,we report a facile and cost-effective in situ electrochemical approach for the synthesis of atomically dispersed metal sites including platinum(Pt),ruthenium(Ru),and palladium(Pd)on the polyaniline(PANI)support.The PANI exhibits not only high electrochemical conductivity but also efficientH+capture fromhydronium ions,leading to the formation of protonated amine groups that can be easily electrochemically reduced to H2 on atomically dispersed metal active sites.As an example,the atomically dispersed Pt sites anchored on carbon cloth-supported PANI(PANI-Pt/CC)demonstrate excellent activity and durability toward the HER.The mass activity of PANI-Pt-10/CC reaches 25 A mg_(Pt)^(−1),exhibiting a significant enhancement of 50-fold compared to that of the commercial Pt/C(0.5 A mg_(Pt)^(−1)).Therefore,this study presents a universally applicable approach for the design of atomically dispersed metal sites/conducting polymer heterostructures for highly efficient catalysts toward HER and beyond.
基金the National Key R&D Program of China(2017YFA0700102)the National Natural Science Foundation of China(22125205,22102175,92045302,22072146,and 21688102)+3 种基金Dalian National Laboratory for Clean Energy(DNL201923)the“Transformational Technologies for Clean Energy and Demonstration”Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21070613)China Postdoctoral Science Foundation(2021M693124)G.X.Wang thanks the financial support from CAS Youth Innovation Promotion(Y201938).
文摘The sluggish reaction kinetics of CO_(2)electroreduction in perovskite-based cathodes severely limits the efficiency of solid oxide electrolysis cells(SOECs).The construction of the high-density active sites on the perovskite sur-face is crucial for promoting CO_(2)electrolysis in SOEC.In this study,we explore a redox-induced redispersion strategy to produce RhO_(x)nanoclusters uniformly anchored on a Sr_(2)Fe_(1.45)Rh_(0.05)Mo_(0.5)O_(6-δ)(SFRhM)perovskite surface with a high density of 36,000μm^(−2).Compared with non-uniformly distributed RhO_(x)nanoparticles on Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)(RhO_(x)/SFM)prepared by a conventional impregnation process,the successive reduction and oxidation treatment first exsolves the highly dispersed RhFe alloy nanoparticles on SFRhM and then selectively dissolves the iron species in the RhFe alloy nanoparticles into the bulk of SFRhM,resulting in fully exposed RhO_(x)nanoclusters uniformly anchored on the SFRhM surface(RhO_(x)@SFRhM).Electrochemical measurements and density functional theory calculations indicate that the high-density RhO_(x)@SFRhM interfaces promote CO_(2)adsorption and activation during CO_(2)electrolysis,thus leading to improved electrocatalytic activity and stability compared to that of its SFRhM and RhO_(x)/SFM counterparts.
基金We gratefully acknowledge the financial support of this research by the National Natural Science Foundation of China （No. 51572052）, the Natural Science Foundation of Heilongjiang Province of China （No. LC2015004）, the China Postdoctoral Science Special Foundation （No. 2015T80329）, the Major Project of Science and Technology of Heilongjiang Province （No. GA14A101） and the Project of Research and Development of Applied Technology of Harbin （No. 2014DB4AG016）.
文摘A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH4 oxidation in alkaline solution. The morphology and phase composition of PtCo/C0304 NSs are characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy （XPS）. The catalytic performance of PtCo/Co3O4 NSs is investigated by cyclic voltammetry （CV） and chronoamperometry （CA） in a standard three-electrode system. Current densities of 70 and 850 mA·cm^-2 were obtained at -0.4 V for Co/Co3O4 and PtCo/Co3O4 NSs, respectively, in a solution containing 2 mol·L^-1 NaOH and 0.2 mol·L^-1 NaBH4. The use of a noble metal （Pt） greatly enhances the catalytic activity of the transition metal （Co） and Co3O4. Besides, both Co and Co3O4 exhibit good B-H bond breaking ability （in NaBH4）, which leads to better electrocatalytic activity and stability of PtCo/Co3O4 NSs in NaBH4 electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co3O4 NSs can be a promising electrocatalyst for borohydride oxidation.
基金supported by the National Natural Science Foundation of China(22001236)the Program for Innovative Research Team(in Science and Technology)in Universities of Henan Province(19IRTSTHN022)Zhengzhou University。
文摘结合了三维结构和亲锌物种的集流体构筑策略被认为是构建高稳定锌金属负极的有效方法.然而,高昂的成本和复杂的制备工艺阻碍了其实际应用.本文通过在有均匀Cu^(2+)锚定的碳布集流体(ACC-600@Cu^(2+))上沉积锌,合理设计了一种稳定的三维锌金属复合阳极(Zn@ACC-600@Cu^(2+)).在锌成核过程中,Cu^(2+)原位还原为金属Cu,然后随着锌的进一步沉积,碳布表面逐渐形成均匀的亲锌的Cu-Zn合金界面层.密度泛函理论计算和实验观察表明,Cu-Zn合金界面不仅可以作为锌离子的亲锌沉积点,而且可以提高导电率,使电场和锌离子通量均匀化.因此,ACC-600@Cu^(2+)集流体可以实现高的镀锌/剥离可逆性,并在15.8 mV的极化电压下稳定循环410 h以上.作为概念验证,我们组装的Zn@ACC-600@Cu^(2+)‖MnO_(2)全电池具有良好的电池倍率性能,与原始碳布相比,其比容量显著提高至110 mA h g^(-1).本文提出的原位还原策略为三维锌金属复合负极的设计提供了一种简便且低成本的方法,促进了无枝晶和高稳定锌金属电池的发展.
基金financially supported by National Natural Science Foundation of China(No.22208114)Science and Technology Planning Project of Guangzhou City(No.202201010178)+1 种基金China Postdoctoral Science foundation(2022M721195)Leading Talents in the Yellow River Delta Industry
文摘Reduced graphene oxide(rGO)films suffer from low capacitance for inner unreduced oxygen functional groups,restacking of sheets and high contact resistance.Herein,carbon spheres derived from renewable xylan were added to graphene oxide with large sheet area to fabricate film by gelation and filtration,followed by in situ reduction for high-performance flexible supercapacitor.rGO film with transverse size about 13 pm showed a good specific capacitance of 967 mF/cm^(2) at a scanning rate of 5 mV/sand increased to 1786 mF/cm^(2) by in situ reducing its inner part,which generally remained oxidized due to outer hindering from hydrophobic graphene.Then,by hydrothermal carbonization of xylan and activation with KOH,activated carbon sphere(aXCS)was prepared,which had a diameter of 150-200 nm and a specific capacitance of 270 F/g.The aXCS acted as spacer and connector to avoid restacking of graphene sheets and decrease interlayer contact resistance,resulting 94%increase in capacitance performance from rGO film to aXCS/rGO film.Therefore,combined in situ reduction and enhancement through compositing aXCS,the final film(aXCS/rGO-AA)showed a boosted specific capacitance of 755 mF/cm^(2) at 1 mA/cm^(2) in double electrode system,power density of 22.5-2250 mW/cm^(2),and energy density of 11.88-25.2 mWh/cm^(2).Meanwhile,aXCS/rGO-AA had outstanding cycling stability that its specific capacitance maintained 108.7%after 10,000 cycles of charge-dis-charge,showing promising potential in wearable and portable electronics.
