MSGID: 1:317/3 640ab275   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Electrocatalysis under the atomic force microscope    
      
     Date:   
         March 9, 2023   
     Source:   
         Helmholtz-Zentrum Berlin fu"r Materialien und Energie   
     Summary:   
         A further development in atomic force microscopy now makes   
         it possible to simultaneously image the height profile of   
         nanometer-fine structures as well as the electric current and the   
         frictional force at solid-liquid interfaces. A team has succeeded   
         in analyzing electrocatalytically active materials and gaining   
         insights that will help optimize catalysts. The method is also   
         potentially suitable for studying processes on battery electrodes,   
         in photocatalysis or on active biomaterials.   
      
      
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   FULL STORY   
   ==========================================================================   
   A further development in atomic force microscopy now makes it possible to   
   simultaneously image the height profile of nanometre-fine structures as   
   well as the electric current and the frictional force at solid-liquid   
   interfaces. A team from the Helmholtz-Zentrum Berlin (HZB) and the   
   Fritz Haber Institute (FHI) of the Max Planck Society has succeeded in   
   analysing electrocatalytically active materials and gaining insights that   
   will help optimise catalysts. The method is also potentially suitable   
   for studying processes on battery electrodes, in photocatalysis or on   
   active biomaterials.   
      
      
   ==========================================================================   
   To manage the energy transition, it will also be important to   
   rapidly develop cheap and efficient materials that can be used to   
   split water or CO2 by electrocatalysis. In this process, part of the   
   electrical energy is stored in the chemical reaction products. The   
   efficiency of such electrocatalysts depends largely on the nature of   
   the electrode-electrolyte interfaces, i.e. the interfaces between the   
   solid electrodes and the typically aqueous electrolyte.   
      
   However, spatially resolved physical studies of such solid-liquid   
   interfaces are still relatively scarce.   
      
   More insights with AFM Dr Christopher S. Kley and his team have now   
   developed a new approach to correlative atomic force microscopy   
   (AFM). An extremely sharp tip is scanned across the surface and   
   its height profile is recorded. By attaching the tip to the end of a   
   miniaturised cantilever, the force interactions between the tip and the   
   sample surface, including frictional forces, can be measured with high   
   sensitivity. In addition, the electrical current flowing through the   
   mechanical contact can be measured, provided a voltage is applied. "This   
   allowed us to simultaneously determine the electrical conductivity, the   
   mechanical-chemical friction and the morphological properties in situ   
   (i.e. under the relevant liquid-phase conditions rather than in vacuum   
   or in air)," emphasises Kley.   
      
   Copper-gold electrocatalyst Using this method, the scientists now   
   studied a nanostructured and bimetallic copper-gold electrocatalyst,   
   in collaboration with Prof. Beatriz Rolda'n Cuenya from the   
   Fritz-Haber-Institute (FHI). Among others, such materials are used in   
   the electrocatalytic conversion of CO2 into energy carriers. "We were   
   able to clearly identify islands of copper oxide with higher electrical   
   resistance, but also grain boundaries and low-conductivity regions in   
   the hydration layer where the catalyst surface comes into contact with   
   the aqueous electrolyte," says Dr Martin Munz, first author of the study.   
      
   Such results on catalyst-electrolyte interfaces help to optimise them   
   in a targeted manner. "We can now observe how local electrochemical   
   environments influence charge transfer at the interface," says Kley.   
      
   Focus on solid-liquid interfaces "However, our results are also of general   
   interest to energy research, especially for the study of electrochemical   
   conversion processes, which also play a role in battery systems." Insights   
   into solid-liquid interfaces can also be useful in completely different   
   areas of research, such as understanding corrosion processes, nanosensor   
   systems, and possibly addressing scientific queries in fluidics and   
   environmental sciences, such as dissolution or deposition processes on   
   metal surfaces exposed to water.   
      
   This work was carried out within the framework of the CatLab project,   
   where researchers from the HZB and the FHI of the MPG are working   
   together, to develop thin-film catalysts for the energy transition.   
      
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Energy_Technology # Energy_and_Resources #   
                   Fuel_Cells # Nature_of_Water # Spintronics # Graphene #   
                   Materials_Science # Physics   
       * RELATED_TERMS   
             o Friction o Battery_electric_vehicle o Ampere o   
             Potential_energy o Torque o Energy o Propellant o Magnetic_field   
      
   ==========================================================================   
   Story Source: Materials provided by   
   Helmholtz-Zentrum_Berlin_fu"r_Materialien_und_Energie.   
      
   Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Martin Munz, Jeffrey Poon, Wiebke Frandsen, Beatriz Roldan Cuenya,   
         Christopher S. Kley. Nanoscale Electron Transfer Variations   
         at Electrocatalyst-Electrolyte Interfaces Resolved by in Situ   
         Conductive Atomic Force Microscopy. Journal of the American Chemical   
         Society, 2023; 145 (9): 5242 DOI: 10.1021/jacs.2c12617   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/03/230309124941.htm   
      
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