A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co₃O₄ nanosheets (PtCo/Co₃O₄ NSs) supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH₄ oxidation in alkaline solution. The morphology and phase composition of PtCo/Co₃O₄ NSs are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalytic performance of PtCo/Co₃O₄ NSs is investigated by cyclic voltammetry (CV) and chronoamperometry (CA) in a standard three-electrode system. Current densities of 70 and 850 mA·cm^–2 were obtained at–0.4 V for Co/Co₃O₄ and PtCo/Co₃O₄ NSs, respectively, in a solution containing 2 mol·L^–1 NaOH and 0.2 mol·L^–1 NaBH₄. The use of a noble metal (Pt) greatly enhances the catalytic activity of the transition metal (Co) and Co₃O₄. Besides, both Co and Co₃O₄ exhibit good B–H bond breaking ability (in NaBH₄), which leads to better electrocatalytic activity and stability of PtCo/Co₃O₄ NSs in NaBH₄ electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co₃O₄ NSs can be a promising electrocatalyst for borohydride oxidation.