Different structures of the cuprous oxide nanoparticles with cubic, truncated-octahedral and octahedral morphology were developed for sensing hydrogen peroxide. The structure and composition of the prepared cuprous oxide were examined by SEM, XRD, EDS, and TEM. The cyclic voltammetry and amperometric analysis were carried out to analyze the catalytic ability. The results indicate that the octahedral cuprous oxide nanoparticles (similar to 100 nm) with {111} facets have the best sensitivity of 28.0 mu AmM(-1)cm(-2), which is better than the reported hydrogen peroxide sensors in the linear range of 0.5-3mM. Selectivity of the sensor among hydrogen peroxide and interferents also has a superior performance. (c) 2019 The Electrochemical Society.