Size-Dependent Oxidation of Copper Nanostructured Electrocatalysts Produced by Spark Ablation

Nanostructured materials play a crucial role in today's society and are widely used across a range of fields, from catalysis to energy storage systems. However, their synthesis and characterization are often time-, cost-, and energy-consuming. This study aims to develop relatively simple approaches for upscaling size-selected nanoparticle synthesis via a plasma-based physical strategy and for determining particle sizes using electrochemical methods. We present a scalable, cost-effective spark ablation synthesis strategy that enables the production of high-purity, non-agglomerated copper (Cu) nanoparticles, directly immobilized on a carbon support, without the use of reducing agents or surfactants. This approach achieves high collection efficiency and imposes no limitations on attainable mass loading. To address challenges in nanoparticle size characterization, we introduce a simple electrochemical approach, namely anodic potential sweep oxidation, for determining particle size based on the size-dependent oxidation potential. For the produced Cu nanoparticles, a strong linear correlation (R ² = 0.99) was observed between particle radius and oxidation peak potential. This study demonstrates that the size of approximately spherical Cu nanoparticles can be estimated by simple, cost-effective electrochemical measurements, without the need for complex microscopy techniques. That opens a perspective for the express-assessment of particle size changes during various physicochemical processes, e.g., catalytic reactions.