In particular, we observe that the density of these islands was highest for the sample kept at 1.2 V in the 25 mM H2O electrolyte, by more than an order of magnitude compared to the sample kept at 0.1 V and the dry references (Table ). While none of these features can be linked directly to the columnar deposition due to their sparsity and size, these islands appear to originate from the reduction process at 1.3 V in the presence of water.