In this work, Ce-doped Co/CoO grown on carbon nanotubes was prepared by a novel Joule-heating method. The rapid heating and cooling process caused lattice disorder, which effectively exposed active sites and further improved electrocatalytic activity in the hydrogen evolution reaction (HER). As prepared Ce-Co/CoO@CNTs by the rapid Joule-heating method exhibited excellent performance with an overpotential of only 47.6 mV @10 mA cm−2 in 1 M KOH electrolyte. Furthermore, as-prepared samples maintained exceptional chemical stability, with almost no decay observed even at high current densities (700 mA cm−2) for 200 h. In addition, using Ce-Co/CoO@CNTs catalyst in the alkaline exchange membrane (AEM) electrolyzers, an outstanding operating performance (1.62 V at 10 mA cm−2) was tested for overall water splitting. The formation of a large number of surface defects increased the number of active sites and accelerate the charge transfer. Additionally, the construction of Co/CoO heterojunctions modulated the electronic structure of the interfacial domains, optimizing reaction kinetics and providing a new pathway for designing and synthesizing efficient HER catalysts.