NOMATEN HYBRID-SEMINAR November 29: Preparation and activity analysis of nanomaterials with scanning electrochemical microscopy

NOMATEN HYBRID-SEMINAR

online: https://www.gotomeet.me/NCBJmeetings/nomaten-seminar
In-person: Proton 251 seminar room, PNT, NCBJ

Tuesday, NOVEMBER 29^th  2022 13 CET

Preparation and activity analysis of nanomaterials with scanning electrochemical microscopy

Dr. Wojciech Nogala
Institute of Physical Chemistry, Polish Academy of Sciences Warsaw, Poland.

Abstract:

     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 the catalytic properties of such prepared nanostructures by hindering access of reactants to the catalyst surface. Electrochemical methods allow the 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.

Bio:

Wojciech Nogala is working in electrochemistry since 2005. In his academic journey, he had an opportunity to explore several aspects of this branch of science. Starting with an analysis of solid oxide fuel cells, following through enzymatic cathodes for fuel cells, catalysis and ion transfer across a liquid-liquid interface, gas diffusion electrodes, nucleation and growth of metallic nanostructures for electrocatalysis and surface-enhanced Raman spectroscopy, voltammetric nanosensing of pH, electroactuation, materials for sodium ions intercalation, supercapacitors and redox charging at voltages beyond water electrolysis. Besides his intrinsic interest in energy conversion, Wojciech Nogala is focused on understanding the processes at the nanoscopic level and analyzing them at the edge of their detection, especially with nanoelectrodes and scanning electrochemical microscopy.