Recently, three-dimensional (3D) zinc oxide nanoarchitectures (3D ZnO NAs) have drawn significant research attention due to their excellent stability, environmental friendliness and low cost. However, many of the synthesis methods are complicated, such as the two-step method. Hence, it is crucial to develop a facile hydrothermal approach. We report 3D firecracker-like zinc oxide nanoarchitectures on Zn piece that were fabricated via a facile, one-step hydrothermal approach without any surfactants. The as-prepared 3D firecracker-like ZnO nanoarchitectures/Zn piece are investigated as an integrated electrode (called 3D ZnO NA/ZPIE) and show high electrocatalytic performance to hydrazine, suggesting that 3D ZnO NA/ZPIE has potential applications in the catalytic field. At the same time, the photocatalytic activities of the prepared samples were evaluated by photocatalytic degradation of methyl orange (MO) aqueous solution at ambient temperature under UV-light irradiation. The results exhibit strong UV-light absorption capability, high degradation rate, and greatly enhanced photocatalytic (PC) activity toward degradation of methyl orange (MO) aqueous solutions under UV-light irradiation.