SERS Reveals the Presence of Au-O-O-H and Enhanced Catalytic Activity of Electrochemically Dealloyed AgAu Nanoparticles

Due to their high surface-to-volume ratio and large proportion of low coordinated surface atoms, dealloyed nano particles have gained increasing attention as porous catalysts for the electrochemical oxygen evolution reaction (OER). Here, we characterize and rationalize the physical and chemical properties of operando gold-enriched porous nanoparticles fabricated by electrochemical dealloying of citrate-capped silver gold alloy nanoparticles in 250 mM KNO3. We combine surface-enhanced Raman spectroscopy (SERS) with electrochemistry for catalyst tracking. With SERS, we observe at 1.05 V (vs platinum quasi reference electrode) the formation of Au-O-O-H species, a known intermediate of OER, while this is not observed for monometallic gold nanoparticles or bare electrodes. In agreement, qualitative measurements of the catalytic activity prove that appreciable OER currents are detected at lower potentials for gold enriched porous nanoparticles compared to gold nanoparticles of the same size. Our results pave the way for the application of dealloying-derived nanoparticles as promising catalyst materials.

Automated summary

Due to their unique surface properties, gold-enriched porous nanoparticles fabricated by electrochemical dealloying show enhanced catalytic performance for the electrochemical oxygen evolution reaction (OER) compared to monometallic gold nanoparticles or bare electrodes. Surface-enhanced Raman spectroscopy (SERS) combined with electrochemistry confirmed the formation of Au-O-O-H species, a known intermediate of OER, at a specific potential. These results highlight the potential application of dealloying-derived nanoparticles as promising catalyst materials.