New Insight into Platinum Dissolution from Nanoparticulate Platinum-Based Electrocatalysts Using Highly Sensitive In Situ Concentration Measurements

Time- and potential-resolved electrochemical Pt dissolution from commercial Pt and prepared PtCu alloy nanoparticulate catalysts have been studied under potentiodynamic conditions in 0.1M HClO4 by using on-line inductively coupled plasma mass spectrometry (ICP-MS). For the first time the exact amount of dissolved Pt per cycle has been measured on real electrocatalysts. Results show clearly that Pt dissolution depends on the particle size: approximately seven times as much Pt is released into the solution from commercial 3 nm Pt particles as from a commercial 30 nm Pt sample. The stability of our prepared PtCu electrocatalyst is higher than that of a commercial 3 nm electrocatalyst, which is, however, still slightly lower than that of a commercial 30 nm Pt electrocatalyst.