Here we first confirm the successful deposition of Rh on the Ni-poly electrode. The exchange was done for 10 and 30 seconds, as we have previously shown that longer deposition times for smooth Ni electrodes do not enhance further HER activity. However, previously we have not observed Rh HUPD peaks for 10 s exchange (mirror-finish polished Ni-poly), while here could clearly observe these features in cyclic voltammogram (Figure . Upon extending the deposition time to 30 seconds, the peaks roughly double in size and become more prominent. The cycling of the electrode to progressively higher anodic potentials (Figure ) reveals that the main surface electrochemistry of Rh is well-separated from the main features of Ni electrochemistry (Figure , b), also suggesting that after 30 s of galvanic exchange, the Ni-poly surface is only partially covered with Rh. Besides the already mentioned HUPD peaks of Rh (0.05 to 0.3 V vs. RHE), the oxidation of the Rh phase takes place already at E > 0.4 V vs. RHE. Similarly to other noble metals, like Pt , the oxidation and reduction of the Rh phase are characterized by pronounced irreversibility, and for the case of Rh, we observe an extreme behavior. Namely, as the anodic vertex goes deeper into the anodic direction, the reduction of Rh oxide shifts to progressively more negative potentials. When the electrode is cycled up to 1.45 V vs. RHE, the reduction of Rh oxide shifts to very negative potentials, practically overlapping with the HUPD region. This could also explain the smaller anodic peak of HUPD upon progressively deeper anodic excursions of Rh-modified Ni-poly. One logical assumption would be that Rh is lost from the surface layer, as it is known that there is anodic dissolution of Rh upon anodic excursions . However, the Rh dissolution rate at high anodic potentials (corresponding to OER conditions) in alkaline media is lower compared to Ru and Ir, and slightly higher compared to that of Pt and Pd. On the other hand, under potential cycling, the Rh dissolution rate is the lowest among the metals considered by Schalenbach et al. (Ag, Au, Ir, Pd, Pt, Rh, and Ru). Thus, the reduction of the anodic HUPD peak can be ascribed to the cathodic contribution of hardly reducible Rh oxide reduction upon anodic excursions.