Preparation and activity analysis of nanomaterials with scanning electrochemical microscopy | Faculty of Applied Physics and Mathematics at the Gdańsk University of Technology

Nanostructured metallic catalysts are usually obtained by homogeneous synthesis. Then one needs to apply capping agents to stop the growth of nanostructures and prevent their aggregation. Capping agents affect catalytic properties of such prepared nanostructures by hindering access of reactants to the catalyst surface. Electrochemical methods allow direct synthesis of nanostructures immobilized on electrodes without sapping agents.

We employed scanning electrochemical microscopy (SECM) to prepare bare metallic nanostructures (Au, Cu, Ag) directly by localized electrorefining of polycrystalline metal. By changing the physicochemical parameters of the process, one can tailor the size and shape of obtained nanostructures. Besides electrocatalytic properties towards reduction of oxygen, carbon dioxide and hydrogen evolution, bare gold nanostructures can be used as supports for surface-enhanced Raman spectroscopy (SERS).

SECM is also powerful for imaging of activity of heterogeneous catalysts. However, mapping of rough surfaces is demanding because the recorded signal depends on tip-to-sample distance. We developed a method of simultaneous mapping of activity and topography with nanoelectrode tips and mapping of pH near solid surfaces.