The role of graphene oxide (GO)/reduced graphene oxide (rGO) in the 3-aminopropyltrimethoxysilane (3-APTMS)-mediated synthesis of gold nanoparticles (AuNPs) in the presence of formaldehyde is reported. It was found that 3-APTMS-functionalized GO/rGO allowed the rapid conversion of gold cations into AuNPs in the presence of formaldehyde. Moreover, the major findings include (i) the process of nanoparticle synthesis is 3-fold faster (2–3 min) in the presence of GO as compared to that of the same process without GO (15–20 min) under similar conditions, (ii) the AuNPs prepared in the presence of GO show a relatively better stability, which is attributed to the synergistic response of oxygen functionalities on the surface of GO and the micellar behaviour of 3-APTMS, (iii) the average size of the Au–GO nanohybrids is significantly reduced to the order of 3–4 nm as compared to that of the same without GO (5–12 nm), (iv) the Au–GO nanohybrid exhibits distinguished homogeneous catalytic behaviour over AuNPs made without GO and (v) the Au–rGO nanohybrid displays heterogeneous electrocatalytic activity due to the conductive nature of rGO and allows nanocomposite formation with Prussian blue nanoparticles. The high catalytic performance of Au–GO and Au–rGO in the homogenous and heterogenous operations is a function of the structural framework of the substrates and the morphological characteristics of the nanoparticles, as evidenced by FTIR, TEM, EDS and UV-Vis analysis.