Unsupported Pt nanoparticles: Synthesis, Deactivation, and Hydrogen Electrocatalysis in Unpurified Electrolytes

We synthesized clean unsupported Pt nanoparticles (NPs) which can be used for any electrochemical measurements without the need for additional cleaning steps. In this report, we demonstrated the use of these unsupported Pt NPs for electrochemical reactions involving hydrogen. We further identified conditions under which Pt NPs deactivate in unpurified, reagent grade acid, and alkaline electrolytes, and differentiated between degradation mechanisms involving catalyst poisoning and particle growth. We monitored the degradation of Pt NPs as a function of a decrease in the electrochemically active surface area (ECSA) at different applied potentials. The results obtained from the ECSA measurements were then correlated with the identical location transmission electron microscopy (IL-TEM) observations. At potentials less than 1 V vs RHE, catalyst poisoning was found to be a dominant cause for degradation while particle growth was dominant at 1.5 V vs RHE in both acid and alkaline electrolytes.