Effect of the pH on the Formation of Gold Nanoparticles Enabled by Plasma‐Driven Solution Electrochemistry

ABSTRACT Plasma‐driven solution electrochemistry offers alternatives to wet‐chemical methods for synthesizing nanomaterials. This study examines how precursor solution pH affects gold nanoparticle formation, specifically the conversion of precursor ions by solvated electrons and H 2 O 2 , and particle size. Our experiments show that –enabled autocatalytic reduction selectivity is 43%–65%, suggesting a catalytic decomposition of by gold nanoparticles. The solubility of gold monomers, increasing with decreasing pH, influences nucleation and resulting particle size, affecting the particle size distribution significantly at pH between 3 and 5. A 1‐D film reaction‐diffusion model quantitatively reproduces and explains the experimental results, demonstrating the impact of pH on different plasma‐produced species, enabling the gold ion conversion and nucleation rates, which directly impact particle size distributions.