Figure 4.

Au dissolution as a function of the applied electrochemical protocol in the EFC-ICP-MS system in 0.05 M H₂SO₄. (a) applied potential protocol: activation (20 cycles, 100 mV/s, 0.28–1.58 V_RHE), a set of 3 cycles (20 mV/s) from 0.28 V_RHE to a given UPL (1.31, 1.41, 1.51, and 1.61 V_RHE). Then, the material was subjected to 500 cycles of AST (1 V/s, 0.58–1.41 V_RHE) before the profiling was repeated to analyze the degradation-induced changes. The sequence of degradation and profiling was repeated once more. After each AST protocol, the electrolyte flow was switched from one syringe to another, causing a signal peak unrelated to sample dissolution. A close-up of all the protocols is available in Figure S5a–f. Three profiling cycles (marked with *) with an UPL of 1.61 V_RHE are selected for comparison of the dissolution profile (b) before AST, (c) after the first 500 AST cycles, and (d) after the second 500 cycles.