Interfacial charge transfer in Z-scheme CeO2/AgFe2O3 heterojunction for the photocatalytic degradation of atrazine and electrochemical performance

We report a hydrothermally synthesized CeO 2 /AgFe 2 O 3 heterojunction designed to simultaneously enhance visible-light photocatalytic activity and electrochemical energy-storage performance. The intimate interfacial contact between CeO 2 and AgFe 2 O 3 promotes efficient charge separation via a heterojunction-mediated transfer pathway, suppressing electron-hole recombination under visible-light irradiation, as revealed by spectroscopic, structural and surface analyses (XRD, FTIR, SEM–EDS, XPS, BET). UV–Vis DRS shows red-shifted absorption (Eg: CeO 2 2.81 eV; AgFe 2 O 3 1.75 eV; composite 2.35 eV), while Mott–Schottky plots indicate n-type CeO 2 and p-type AgFe 2 O 3 with flat-band potentials of − 0.41 V and + 0.02 V, respectively, supporting a direct Z-scheme band alignment. This synergistic interaction significantly improves the photocatalytic degradation efficiency, increasing it by 93.54 % in 60 min, with a pseudo-first-order rate constant 5 times and 2 times higher than those of CeO 2 and AgFe 2 O 3, respectively. Radical-trapping experiments implicate •OH and •O 2 − as the dominant reactive species, consistent with the Z-scheme pathway that preserves strongly oxidising VB holes on AgFe 2 O 3 and reducing CB electrons on CeO 2 . Total organic carbon analysis further confirmed partial mineralization of atrazine, demonstrating the catalyst’s ability to degrade the pollutant into smaller intermediates and mineral products. The enhanced photocatalytic activity is attributed to the synergistic effects of the p–n heterojunction structure, increased surface area, improved visible-light absorption, and the surface plasmon resonance effect of Ag species, which enhances interfacial charge transfer and reactive oxygen species generation. As a supercapacitor electrode, the composite delivers a specific capacity of 146.8mAh g −1 at 0.5 A g −1 within 0.0–0.4 V (vs Ag/AgCl), 98.9 % coulombic efficiency, and 77.1 % capacity retention after 5000 cycles at 10 A g −1 . The dual-functional performance demonstrates that rational heterojunction engineering is an effective strategy for integrating environmental remediation and energy storage within a single material platform.