Intermediate Valence Ion-Mediated Electrodeposition Process.

The assembly of biomolecules and ions (e.g., biomineralization process) generates many intricate structures in nature. However, human beings' control over the assembly processes of ions is in its infant stage compared with nature. Here, it is reported that the intermediate valence metal ions in the electrolyte can influence the growth speed of certain crystal facets and in turn adjust the shape of the electrodeposits created by anodic electrodeposition. This is because the intermediate valence metal ions (e.g., Pb 2+ , Mn 2+ , etc.) can be oxidized by the electrochemically oxidized high valence ions (e.g., Ag 2+ and Ag 3+ ). Therefore, the concentration of the electrochemically oxidized high valence ions can be controlled by the intermediate valence ions, affecting the growth kinetics of the electrodeposits. Taking the anodic electrodeposition of Ag 7 O 8 NO 3 as an example, the role of intermediate valence ions in tailoring the shape of the Ag 7 O 8 NO 3 electrodeposits is demonstrated. Moreover, the growth location of the second-order structure can be controlled by the intermediate valence metal ions. Additionally, the designed complex microarchitectures starting from certain crystal facets to form hollow nanoframes can be selectively etched. The control capability over the electrochemical assembly process of metal ions is significantly strengthened by introducing intermediate valence ions into the electrolyte.