Optimizing the electrochemical properties of carbon-based nanocomposites is a fundamental challenge for sensor applications. In this work, the optimization of the electrochemical properties of silver nanocomposites on graphene oxide was studied for the fabrication of a non-enzymatic hydrogen peroxide (H2O2) sensor. To do so, we transform silver nanoparticles (AgNP) into silver nanoplates (AgNC) and anchor them to graphene oxide (GO) via the photochemical reduction method at 540 nm irradiation wavelength for its deposition on the surface of graphite electrodes (GE) and detect low concentrations of H2O2. We performed a physicochemical characterization of the resulting nanocomposite using a combination of UV-Vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy, to then, analyze the electrochemical properties of GE modified with silver nanocomposites by cyclic voltammetry (CV). Our results reveal an improvement of the sensitivity from 309 μA mM−1cm−2 to 444 μA mM−1cm−2 and limits of detection (LOD) and limits of quantification (LOQ) from 0.68 mM and 2.29 mM to 0.28 mM and 0.96 mM using AgNP/GO −GE and AgNC/GO −GE nanocomposites electrodes, respectively. The enhancement of the electrochemical properties reveals a synergistic effect between the planar shape of the AgNC and the oxygen functional groups over the GO surface. In so doing, we have demonstrated the utility of a low-cost photoreduction method to optimize the structural properties of AgNC/GO and, in this way, enhance the electrochemical properties of the modified electrode for H2Osensing. These results should greatly interest a wide range of biomedical applications and medical devices.