Enhanced Control of Single Crystalline Ag Dendritic Growth on Al Foil via Galvanic Displacement and Simultaneous Oxidation of D-Glucose.

A facile synthesis platform for the formation of stable single crystalline Ag dendrites is demonstrated. Using a porous electrospun polyacrylonitrile nanofiber network on Al foil as a template facilitates more uniform dendritic growth in the presence of D-glucose. In contrast, a denser polymer network restricts the nucleation site availability on the Al foil, highlighting the critical role of the substrate. The growth formation of silver dendrites is reduced in the solution when two simultaneous processes occur: The electroreduction of Ag in the D-glucose solution and galvanic displacement driven by the interaction of Ag with the aluminum substrate. High-resolution transmission electron microscopy analysis shows the single crystalline nature of Ag dendrites grown from the Al substrate, revealing atomic structures with closely packed layers forming highly faulted face-centered cubic and hexagonal close-packed structures. The remarkable long-term stability of Ag dendrites is primarily attributed to their single crystalline structure, with additional contributions from capping by D-gluconic acid, as confirmed by Raman analysis. This novel approach to the generation of highly stable Ag dendrites has significant potential for applications such as surface-enhanced Raman scattering, which has to date been considered to be very sensitive to environmental effects.