ABSTRACT Efficiency in Fenton‐like processes is often bottlenecked by the sluggish redox cycling of metal centers. Herein, we report a self‐sustaining and energy‐free catalysis strategy by constructing an intermetallic potential difference‐induced built‐in electric field (BIEF) to drive an “electron relay” within bimetallic spinels (AB 2 O 4 A = Ni, Cu, Zn; B = Co, Fe, Mn). The intrinsic potential gradient between the A‐site and B‐site metals triggers a spontaneous charge redistribution, establishing an atomic‐level electron transmission channel. Experimental results and theoretical calculations reveal that CuCo 2 O 4 possesses the most robust BIEF, which significantly accelerates the “electron relay” for H 2 O 2 activation. This mechanism enables a closed‐loop valence cycling between (Cu(II)/Cu(I) and Co(III)/Co(II)), achieving highly efficient and continuous generation of reactive oxygen species without any external energy input. Consequently, the CuCo 2 O 4 system exhibits a bisphenol A degradation rate that is 2.45 and 5.69 times higher than those of CuFe 2 O 4 and CuMn 2 O 4 respectively, along with exceptional stability across a wide pH range (5–9). When integrated into a hollow fiber membrane, the system demonstrates a high flux of 318 L·m −2 ·h −1 and long‐term operational durability. This work provides a transformative perspective on designing autonomous catalytic systems for sustainable water remediation.
Zeng et al. (Wed,) studied this question.