For oxidation of ethanol, it is also possible to use other noble metals such as palladium (Pd) and platinum (Pt) due to the fact that they have electrocatalytic properties in different electrolytes and pH . However, the scarcity and high cost of these metals have led to the development of new structures and electrode materials; for example, using the metals in the form of nanoparticles and also use them as hybrids in order to limit the quantities of metals used while retaining the electrocatalytic properties. Gold organometallic chemistry permits to design numerous gold-based nanosystems; for example through arylation . In this regard, Laurentius et al. and Mirkhalaf et al. employed diazonium salts for enhancing dispersion of gold nanoparticles and/or attachment to electrode surfaces. Arylation of the nanoparticles is tricky because it should be done in a way that charge transfer within the hybrid interface (electrode-aryl-NPs) should not be hindered. Moreover, arylation of the electrode or the electrode material itself has major effect on the adhesion and stability of the nanoparticles at electrode surfaces . There are different methods for the grafting of aryl groups to metal nanoparticles and other surfaces . The team of Gooding obtained a hybrid layer containing gold nanoparticles and diazonium salts on the surface of the electrode. Initially, they modified the glassy carbon electrodes (GC) surface with the electrochemical method, using diazonium salts 4aminophenyl and 4-thiophenol, and then they grafted gold nanoparticles on diazonium salts grafted through covalent bonds with different captors C, N and S. Various characterizations indicate that the modification is well established and long term stable (in acidic medium). It is an easy, fast, and reliable technique to functionalize GC surfaces with robust attachment of AuNPs. Mirkhalaf et al. showed that the bonding of arylated gold nanoparticles to surfaces can be done through the interactions between long alkyl chains borne by the latter with similar ones from decylphenyl-modified electrode surface. The nanocatalysts were thus found in a local hydrophobic environment at the gold-surface interface and could selectively electrocatalyze oxygen reduction. Gam-Derouich et al. electroarylated gold flat surface for the attachment of AuNPs. The latter were post-arylated in order to trigger radical graftphotopolymerization therefore obtaining nanostructured thin polymer sensing layers of dopamine. This strategy has been extended to the robust deposition of Au and Ag NPs on agrowaste powder particles and carbon nanotubes , Rh-Cu bimetallic NPs to high surface area graphite powder , carbon nanotubes to flexible ITO electrode surface . For electrocatalytic purpose, it is essential to keep the extent of arylation as low as possible to avoid passivation of the nanocatalyst and inhibition of electron transfer. Such a passivation is usually due to the formation of oligoaryl layer . In order to obtain a monolayer, one could arylate the surface with aryl diazonium compounds bearing blocked positions 3 and 5 of the benzenediazonium . In addition, combining such a sterically hindered diazonium salt with a diazonium compound bearing a reactive group will permit to modify surfaces with aryl diazonium mixtures, an elegant way to tune surface arylation for targeted applications .