Impact of self-assembled monolayer templates on electrodeposition of Pt particles

Abstract

Active templating is commonly used to fabricate nanoparticles. We have demonstrated that self-assembled monolayers (SAMs) on gold can be employed as active templates for nanoparticle synthesis. This work further expands the use of active template by evaluating the effect of thiol terminal groups (CH3, COOH and OH) and their chain lengths (C6, C10/C11 and C16) on electrochemical Pt particle growth. The result suggests that the size, distribution and the potential difference (ΔEdep = ELOP - EFOP) between the first observable peak (EFOP) and the last observable peak (ELOP) in the cathodic region, are strongly affected by the terminal groups and their hydrophilicity/hydrophobicity. Methyl terminal groups lead to the expected ΔEdep > 0, but surprisingly resulted in an increase in the particle count with a decrease in the average particle size with increasing thiol length. Both hydrophilic terminal groups demonstrated ΔEdep < 0 with the expected decrease in particle count with an increase in their size by increasing the thiol chain length. The results suggest thiol motion and hydrophobicity significantly influence particle growth behaviour.