Developing highly efficient, steady, and cost-effective heterogeneous catalyst for the in situ production of singlet oxygen (1O2) is the key challenge to advanced oxidation processes. Previous studies usually involve demanding reaction conditions, cumbersome preparation processes, or hazardous chemicals. Herein, a facile ball milling procedure is adopted to design a vacancy-rich iron–cobalt bimetallic heterojunctions (b-CoS2/Fe3O4) catalyst with a core–shell structure, which can convert various inefficient commercial iron oxides and cobalt disulfide into highly active catalysts for dioxygen activation. Both experiment and DFT calculations show that the direct interfacial interaction between the CoS2 and iron oxides, which is introduced by the ball milling, regulates the bond energy of Fe–O, contributing to the excellent reactivity toward molecular oxygen activation. As a result, in the absence of electricity, light, and other oxidants, the strong interaction between CoS2 and Fe3O4 enables the degradation activity of organic pollutants to be significantly enhanced. In addition, we design an automated reactor and apply it to wastewater treatment in continuous flow mode, further revealing the huge potential of the proposed system in environmental remediation.