In this paper, a new electrochemical method for the cathodic electrodeposition of lead oxide-electrochemically reduced graphene oxide (PbO-ERGO) from an aqueous solution was carried out in one-pot in the same solution containing Pb2+ and graphene oxide, leading to the direct formation of crystalline thin films at near-room temperature. XRD was employed to determine the crystallinity index of the PbO-ERGO nanostructures. SEM, XPS, EDS, and UV–visible spectroscopy techniques were employed to analyze the morphological, structural, and optical characteristics of the composite materials. Owing to the rapid charge transport in the composite materials of PbO-ERGO, rapid, and uniform photocurrent responses were observed. In addition, the PbO-ERGO composite electrode exhibited a 40 and 130 fold increase in the photocatalytic performance compared to PbO and ERGO electrodes, respectively. Then, the nanocomposite-modified electrode was applied for the non-enzymatic sensing of H2O2. A linear amperometric response to H2O2 was observed at concentrations in the range from $1 \times 10^{-5}$ to $10\times 10^{-3}$ mol L−1. The sensitivity and detection limit of the PbO-ERGO electrode were estimated as $2.26~\mu \text{A}$ mM−1 cm−2 and $2\times 10^{-7}$ mol L−1, respectively, at a signal-to-noise ratio of 3.0.