Surface/interface engineering of a multimetallic nanostructure with diverse electrocatalytic properties for direct liquid fuel cells is desirable yet challenging.Herein,using visible light,a class of quaternary Pt_(1)...Surface/interface engineering of a multimetallic nanostructure with diverse electrocatalytic properties for direct liquid fuel cells is desirable yet challenging.Herein,using visible light,a class of quaternary Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)ultrathin nanosheets is fabricated and used as high-performance anode electrocatalysts for formic acid-/alcohol-air fuel cells.The modified electronic structure of Pt,enhanced hydroxyl adsorption,and abundant exterior defects afford Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C high intrinsic anodic electrocatalytic activity to boost the power densities of direct formic acid-/methanol-/ethanol-/ethylene glycol-/glycerol-air fuel cells,and the corresponding peak power density of Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C is respectively 129.7,142.3,105.4,124.3,and 128.0 mW cm^(-2),considerably outperforming Pt/C.Operando in situ Fourier transform infrared reflection spectroscopy reveals that formic acid oxidation on Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C occurs via a CO_(2)-free direct pathway.Density functional theory calculations show that the presence of Ag,Bi,and Te in Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)suppresses CO^(*)formation while optimizing dehydrogenation steps and synergistic effect and modified Pt effectively enhance H_(2)O dissociation to improve electrocatalytic performance.This synthesis strategy can be extended to 43 other types of ultrathin multimetallic nanosheets(from ternary to octonary nanosheets),and efficiently capture precious metals(i.e.,Pd,Pt,Rh,Ru,Au,and Ag)from different water sources.展开更多
Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of gr...Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of graphene oxide(GO)and sulfonated graphene oxide(SGO)and crosslinked with sulfosuccinic acid(SSA).The chemical structure was corroborated and suitable thermal properties were found.Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes,a significant reduction of the ethanol solution swelling and crossover was encountered,more relevant for those functionalised with SGO.In general,the composite membranes were stable under simulated service conditions.The addition of GO and SGO particles permitted to buffer the loss and almost retain similar proton conductivity than prior to immersion.These membranes are alternative polyelectrolytes,which overcome current concerns of actual commercial membranes such as the high cost or the crossover phenomenon.展开更多
Ni/Carbon was prepared in two steps： initially cellulose as carbon source and NiCl2·6H2O as catalyst of the carbonization process were submitted to hydrothermal treatment at 200 ℃ and further to thermal treatme...Ni/Carbon was prepared in two steps： initially cellulose as carbon source and NiCl2·6H2O as catalyst of the carbonization process were submitted to hydrothermal treatment at 200 ℃ and further to thermal treatment at 900 ℃ under argon atmosphere. The obtained material contains Ni nanoparticles with face-centered cubic （fcc） structure dispersed on amorphous carbon with graphitic domains. PtRu/C electrocatalysts （carbon- supported PtRu nanoparticles） were prepared by an alcohol-reduction process using Ni/Carbon as support. The materials were characterized by thermogravimetric analysis, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and tested as anodes in single direct methanol fuel cell （DMFC）. The performances of PtRu/C electrocatalysts using Ni/Carbon as support were superior to those obtained for PtRu/C using commercial carbon black Vulcan XC72 as support.展开更多
电催化反应过程涉及固、液、气传输以及电子和质子传导,为确保反应的顺利进行和提高催化剂中贵金属的利用率及延长催化剂的寿命,理想的电催化剂载体必须同时具备高比表面积、导电性好、合适的孔结构、耐腐蚀以及合适的表面基团等.为此,...电催化反应过程涉及固、液、气传输以及电子和质子传导,为确保反应的顺利进行和提高催化剂中贵金属的利用率及延长催化剂的寿命,理想的电催化剂载体必须同时具备高比表面积、导电性好、合适的孔结构、耐腐蚀以及合适的表面基团等.为此,碳载体的改性工作受到关注,常用的方法是通过酸、碱、氧化和高分子等手段改变载体的结构和表面性质,以期接近理想电催化剂载体的要求;同时在开发新型碳载体方面做了更大量的工作.本文简要评述了商品炭载体如碳黑Vulcan XC-72R以及其它的乙炔黑、黑珍珠-2000、Printex XE-2和Ketjen Black EC等碳材料在直接醇燃料电池中的应用,但对纳米碳纤维、碳纳米管、有序多孔碳、中间相碳小球、碳纳米角、碳纳米卷和碳气凝胶等新型碳载体则进行了较全面的评述.与商品碳载体相比,新型碳载体在一定程度上都表现出比XC-72R更优的性能,这主要是因为新型碳材料具有特殊的结构、更高的结晶性能(导电性)和更好的传质能力.展开更多
In this study, hydrothermal carbonization(HTC)was applied for surface functionalization of carbon nanotubes(CNTs) in the presence of glucose and urea. The HTC process allowed the deposition of thin nitrogen-doped carb...In this study, hydrothermal carbonization(HTC)was applied for surface functionalization of carbon nanotubes(CNTs) in the presence of glucose and urea. The HTC process allowed the deposition of thin nitrogen-doped carbon layers on the surface of the CNTs. By controlling the ratio of glucose to urea, nitrogen contents of up to 1.7 wt%were achieved. The nitrogen-doped carbon nanotube-supported Pd catalysts exhibited superior electrochemical activity for ethanol oxidation relative to the pristine CNTs.Importantly, a 1.5-fold increase in the specific activity was observed for the Pd/HTC-N1.67%CNTs relative to the catalyst without nitrogen doping(Pd/HTC-CNTs). Furtherexperiments indicated that the introduction of nitrogen species on the surface of the CNTs improved the Pd(0)loading and increased the binding energy.展开更多
基金supported by the National Natural Science Foundation of China(21571038,22035004)the Education Department of Guizhou Province(2021312)+2 种基金the Foundation of Guizhou Province(2019-5666)the National Key R&D Program of China(2017YFA0700101)the State Key Laboratory of Physical Chemistry of Solid Surfaces(Xiamen University,202009)。
文摘Surface/interface engineering of a multimetallic nanostructure with diverse electrocatalytic properties for direct liquid fuel cells is desirable yet challenging.Herein,using visible light,a class of quaternary Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)ultrathin nanosheets is fabricated and used as high-performance anode electrocatalysts for formic acid-/alcohol-air fuel cells.The modified electronic structure of Pt,enhanced hydroxyl adsorption,and abundant exterior defects afford Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C high intrinsic anodic electrocatalytic activity to boost the power densities of direct formic acid-/methanol-/ethanol-/ethylene glycol-/glycerol-air fuel cells,and the corresponding peak power density of Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C is respectively 129.7,142.3,105.4,124.3,and 128.0 mW cm^(-2),considerably outperforming Pt/C.Operando in situ Fourier transform infrared reflection spectroscopy reveals that formic acid oxidation on Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)/C occurs via a CO_(2)-free direct pathway.Density functional theory calculations show that the presence of Ag,Bi,and Te in Pt_(1)Ag_(0.1)Bi_(0.16)Te_(0.29)suppresses CO^(*)formation while optimizing dehydrogenation steps and synergistic effect and modified Pt effectively enhance H_(2)O dissociation to improve electrocatalytic performance.This synthesis strategy can be extended to 43 other types of ultrathin multimetallic nanosheets(from ternary to octonary nanosheets),and efficiently capture precious metals(i.e.,Pd,Pt,Rh,Ru,Au,and Ag)from different water sources.
基金the support of the European Union through the European Regional Development Funds(ERDF)The Spanish Ministry of Economy,Industry and Competitiveness,is thanked for the research project POLYDECARBOCELL(ENE2017-86711-C3-1-R)The Spanish Ministry of Education,Culture and Sports is thanked for the FPU grant for O.Gil-Castell(FPU13/01916)。
文摘Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of graphene oxide(GO)and sulfonated graphene oxide(SGO)and crosslinked with sulfosuccinic acid(SSA).The chemical structure was corroborated and suitable thermal properties were found.Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes,a significant reduction of the ethanol solution swelling and crossover was encountered,more relevant for those functionalised with SGO.In general,the composite membranes were stable under simulated service conditions.The addition of GO and SGO particles permitted to buffer the loss and almost retain similar proton conductivity than prior to immersion.These membranes are alternative polyelectrolytes,which overcome current concerns of actual commercial membranes such as the high cost or the crossover phenomenon.
基金CNP_q,FAPESPFINEP-MCT-ProH_2 for financial support
文摘Ni/Carbon was prepared in two steps： initially cellulose as carbon source and NiCl2·6H2O as catalyst of the carbonization process were submitted to hydrothermal treatment at 200 ℃ and further to thermal treatment at 900 ℃ under argon atmosphere. The obtained material contains Ni nanoparticles with face-centered cubic （fcc） structure dispersed on amorphous carbon with graphitic domains. PtRu/C electrocatalysts （carbon- supported PtRu nanoparticles） were prepared by an alcohol-reduction process using Ni/Carbon as support. The materials were characterized by thermogravimetric analysis, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and tested as anodes in single direct methanol fuel cell （DMFC）. The performances of PtRu/C electrocatalysts using Ni/Carbon as support were superior to those obtained for PtRu/C using commercial carbon black Vulcan XC72 as support.
文摘电催化反应过程涉及固、液、气传输以及电子和质子传导,为确保反应的顺利进行和提高催化剂中贵金属的利用率及延长催化剂的寿命,理想的电催化剂载体必须同时具备高比表面积、导电性好、合适的孔结构、耐腐蚀以及合适的表面基团等.为此,碳载体的改性工作受到关注,常用的方法是通过酸、碱、氧化和高分子等手段改变载体的结构和表面性质,以期接近理想电催化剂载体的要求;同时在开发新型碳载体方面做了更大量的工作.本文简要评述了商品炭载体如碳黑Vulcan XC-72R以及其它的乙炔黑、黑珍珠-2000、Printex XE-2和Ketjen Black EC等碳材料在直接醇燃料电池中的应用,但对纳米碳纤维、碳纳米管、有序多孔碳、中间相碳小球、碳纳米角、碳纳米卷和碳气凝胶等新型碳载体则进行了较全面的评述.与商品碳载体相比,新型碳载体在一定程度上都表现出比XC-72R更优的性能,这主要是因为新型碳材料具有特殊的结构、更高的结晶性能(导电性)和更好的传质能力.
基金financial support of the National Natural Science Foundation of China(Nos.51672045 and 11374053)Key Program of Universityindustry Collaboration from Science and Technology Department of Fujian Province(No.2015H6009)
文摘In this study, hydrothermal carbonization(HTC)was applied for surface functionalization of carbon nanotubes(CNTs) in the presence of glucose and urea. The HTC process allowed the deposition of thin nitrogen-doped carbon layers on the surface of the CNTs. By controlling the ratio of glucose to urea, nitrogen contents of up to 1.7 wt%were achieved. The nitrogen-doped carbon nanotube-supported Pd catalysts exhibited superior electrochemical activity for ethanol oxidation relative to the pristine CNTs.Importantly, a 1.5-fold increase in the specific activity was observed for the Pd/HTC-N1.67%CNTs relative to the catalyst without nitrogen doping(Pd/HTC-CNTs). Furtherexperiments indicated that the introduction of nitrogen species on the surface of the CNTs improved the Pd(0)loading and increased the binding energy.
