Rapid Electrochemical Fabrication of Porous Gold Nanoparticles for High-performance Electrocatalysis towards Oxygen Reduction

Abstract

Small-size Au nanoparticles (AuNPs) and nanoporous Au films (npAuFs) are two potential catalysts for electrocatalysis, electrochemical analysis and synthesis. However, the large contact resistance among AuNPs and the poor mass transfer within npAuFs significantly limits their electrocatalysis application. Therefore, how to fabricate available high-active Au catalyst with facile and low-cost method is still a big challenge. In this study, porous gold nanoparticles (pAuNPs) were facilely and rapidly fabricated from gold nanoparticle-loaded electrode through a repeated Au/Hg alloying-dealloying process. In situ electrochemical fabrication ensured good electric contact of pAuNPs on the electrode surface; meanwhile, the pAuNPs were in tenths of nanometer length scales, which ensured rapid mass transport near the liquid/solid interface, facilitating the maximum exploitation of the high binding energy sites within nanoporous structures on electrocatalysis. Testing of the pAuNPs at a proof-of-concept level demonstrated its higher electrocatalytical activity than other two structures towards oxygen reduction in both acidic and alkaline media. The ease of sample preparation in combination with high activity suggested that pAuNPs can potentially cause a wide range of practical applications of Au catalysis.