In this paper,an extensive characterisation of a range of carbon blacks(CB)with similar surface area but different surface chemistry is carried out by flow calorimetry,Raman spectroscopy,dynamic water vapour sorption,...In this paper,an extensive characterisation of a range of carbon blacks(CB)with similar surface area but different surface chemistry is carried out by flow calorimetry,Raman spectroscopy,dynamic water vapour sorption,instrumental gas analysis,nitrogen adsorption/desorption and high potential chronoamperometry.Using these carbon materials as supports,Pt/CB electrocatalysts are prepared by microwave-assisted polyol-mediated synthesis in gram scale.Structural,morphological and electrochemical properties of the prepared electrocatalysts are evaluated by X-ray diffraction,transmission electron microscopy,rotating disc electrode and in situ fuel cell characterisation of the corresponding membrane-electrode assemblies.The obtained results allow to establish a relationship between surface chemistry and electrochemical properties useful for the design of Pt/C catalyst layers with high performance and stability.展开更多
This article presents a novel,facile method for studying the kinetics of liquid-phase synthesis of precious metal nanoparticles.The method is particularly suitable for use in concentrated solutions and under condition...This article presents a novel,facile method for studying the kinetics of liquid-phase synthesis of precious metal nanoparticles.The method is particularly suitable for use in concentrated solutions and under conditions involving gas purging and medium stirring.It is based on the continuous measurement of changes in the solution’s color components and the potential of an indicator electrode during the synthesis process.The method was applied to investigate the effect of solution pH on the kinetics of polyol synthesis of Pt nanoparticles and Pt/C electrocatalysts.The obtained Pt/C electrocatalysts demons-trate high structural-morphological and electrochemical characteristics,surpassing commercial analogs.The simplicity and efficiency of the“kinetic control”technique makes it promising for use in various liquid-phase synthesis technologies.展开更多
Ammonia electrooxidation reaction involving multistep electron-proton transfer is a significant reaction for fuel cells,hydrogen production and understanding nitrogen cycle.Platinum has been established as the best el...Ammonia electrooxidation reaction involving multistep electron-proton transfer is a significant reaction for fuel cells,hydrogen production and understanding nitrogen cycle.Platinum has been established as the best electrocatalyst for ammonia oxidation in aqueous alkaline media.In this study,Pt/nitrogen-doped graphene(NDG)and Pt/tungsten monocarbide(WC)/NDG are synthesized by a wet chemistry method and their ammonia oxidation activities are compared to commercial Pt/C.Pt/NDG exhibits a specific activity of 0.472 mA·cm^(-2),which is 44%higher than commercial Pt/C,thus establishing NDG as a more effective support than carbon black.Moreover,it is demonstrated that WC as a support also impacts the activity with further 30%increase in comparison to NDG.Surface modification with Ir resulted in the best electro-catalytic activity with Pt-IrAVC/NDG having almost thrice the current density of commercial Pt/C.This work adds insights regarding the role of NDG and WC as efficient supports along with significant impact of Ir surface modification.展开更多
文摘In this paper,an extensive characterisation of a range of carbon blacks(CB)with similar surface area but different surface chemistry is carried out by flow calorimetry,Raman spectroscopy,dynamic water vapour sorption,instrumental gas analysis,nitrogen adsorption/desorption and high potential chronoamperometry.Using these carbon materials as supports,Pt/CB electrocatalysts are prepared by microwave-assisted polyol-mediated synthesis in gram scale.Structural,morphological and electrochemical properties of the prepared electrocatalysts are evaluated by X-ray diffraction,transmission electron microscopy,rotating disc electrode and in situ fuel cell characterisation of the corresponding membrane-electrode assemblies.The obtained results allow to establish a relationship between surface chemistry and electrochemical properties useful for the design of Pt/C catalyst layers with high performance and stability.
基金The authors thank the Southern Federal University Strategic Academic Leadership Program(Priority 2030)for funding the research and the High-Resolution Transmission Electron Microscopy Shared Use Center(SFedU,Rostov-on-Don)for conducting electron microscopic studies.
文摘This article presents a novel,facile method for studying the kinetics of liquid-phase synthesis of precious metal nanoparticles.The method is particularly suitable for use in concentrated solutions and under conditions involving gas purging and medium stirring.It is based on the continuous measurement of changes in the solution’s color components and the potential of an indicator electrode during the synthesis process.The method was applied to investigate the effect of solution pH on the kinetics of polyol synthesis of Pt nanoparticles and Pt/C electrocatalysts.The obtained Pt/C electrocatalysts demons-trate high structural-morphological and electrochemical characteristics,surpassing commercial analogs.The simplicity and efficiency of the“kinetic control”technique makes it promising for use in various liquid-phase synthesis technologies.
基金the Southern Marine Sciencc and Engineering Guangdong Laboratory(Guangzhou)(Grant No.SMSEGL20SC01)Innovation and Technology Commission(Grant No.ITC-CNERC14EG03)of the Hong Kong Special Administrative Regionstartup funding of Hong Kong University of Science and Technology.
文摘Ammonia electrooxidation reaction involving multistep electron-proton transfer is a significant reaction for fuel cells,hydrogen production and understanding nitrogen cycle.Platinum has been established as the best electrocatalyst for ammonia oxidation in aqueous alkaline media.In this study,Pt/nitrogen-doped graphene(NDG)and Pt/tungsten monocarbide(WC)/NDG are synthesized by a wet chemistry method and their ammonia oxidation activities are compared to commercial Pt/C.Pt/NDG exhibits a specific activity of 0.472 mA·cm^(-2),which is 44%higher than commercial Pt/C,thus establishing NDG as a more effective support than carbon black.Moreover,it is demonstrated that WC as a support also impacts the activity with further 30%increase in comparison to NDG.Surface modification with Ir resulted in the best electro-catalytic activity with Pt-IrAVC/NDG having almost thrice the current density of commercial Pt/C.This work adds insights regarding the role of NDG and WC as efficient supports along with significant impact of Ir surface modification.
