Abstract
The layer-by-layer (LBL) approach has been utilized to self-assemble multilayers films of citrate-stabilized gold nanoparticles (AuNPs) on polycrystalline gold (poly-Au) substrates. 1,4-benzenedimethanethiol (BDMT) was used as a cross linker to bind every two successive AuNPs layers. The transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques were employed to confirm the existence of the alternative layers of AuNPs and BDMT in the self-assembled multilayers film. The AuNPs modified poly-Au electrode showed a significant electrocatalysis towards the reduction of oxygen (a positive potential shift of about 100 mV was observed in the reduction peak potential compared to that obtained at the bare poly-Au electrode). The AuNPs tend to aggregate during their assembling to different extent which markedly depends on the substrate geometry and roughness. An effort was dedicated to understand and control the aggregation phenomenon.