Authors:

Selene Koremenos-Tsebelis

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About Paper:

Cathodic corrosion is the degradation or dissolution of a metal at high negative potentials, and poses both a technological and conceptual challenge in electrochemistry. Despite its prevalence, the underlying mechanisms driving cathodic corrosion remain incompletely understood. This study exploits cathodic corrosion at the tip of a scanning electrochemical microscopy (SECM) probe, a technique that uses a small electrode to interact with surfaces at the microscale, to achieve controlled deposition of metal nanoparticles. We hypothesize that high current densities at the electrode tip drive hydrogen evolution reactions (HER), generating hydrogen intermediates that destabilize the metal surface and release metal species into the small gap between the probe tip and the substrate. These released metal species then nucleate and deposit as nanoparticles on the underlying surface. To test this, ultramicroelectrodes (UMEs) with diameters on the order of micrometers composed of varying metals including platinum (Pt), palladium (Pd), gold (Au), and silver (Ag) are fabricated and positioned in close proximity to substrates in aqueous electrolyte solutions. Deposited nanoparticles are characterized both morphologically and compositionally using standard microscopy and analytical techniques. This study aims to quantitatively analyze nanoparticle deposition, better comprehend the chemical principles governing cathodic corrosion and hydrogen evolution, and advance SECM-based techniques using ultramicroelectrodes. Ultimately, this work seeks to use the electrochemical process as a controllable tool for precise nanoscale material fabrication.

Source:

Chicago Area Undergraduate Research Symposium

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Co-authors:

Selene Koremenos-Tsebelis