Interfacial Engineering for Enhanced Low-Temperature Catalysis and Magnetic Hyperthermia in Fe 3 O 4 /CeO 2 /Pt Ternary Heterostructures

Carbon monoxide (CO) emission during the cold-start period remains a major bottleneck for automotive aftertreatment systems. Herein, we report the rational design of Fe 3 O 4 /CeO 2 /Pt ternary heterostructures, integrating magnetic induction heating with efficient low-temperature CO oxidation. In this ternary heterostructures, Fe 3 O 4 is successfully encapsulated by a CeO 2 shell and the uniform distribution of Pt nanoparticles. Interfacial engineering induces a mixed Ce 3+ /Ce 4+ valence state, generating abundant oxygen vacancies and promoting electron transfer to Pt, thereby creating electron-deficient Pt sites and enhanced ferromagnetic coupling. Magnetic measurements reveal that Fe 3 O 4 /CeO 2 /Pt exhibits a high saturation magnetization (117.49 emu g -1 ) and a robust hysteresis loop, enabling efficient magnetothermal conversion under an alternating magnetic field (AMF). Consequently, Fe 3 O 4 /CeO 2 /Pt achieves complete CO conversion at 105 °C under AMF heating, with T 50 and T 90 values of 92.9 and 100.0 °C, significantly outperforming Fe 3 O 4 /Pt and reducing the lightoff temperature by 42.0 °C compared to conventional heating. In contrast, non-magnetic CeO 2 /Pt fails to generate heat under AMF. This work demonstrates that the Fe 3 O 4 /CeO 2 /Pt heterostructure leverages interfacial oxygen vacancies and magnetic hyperthermia to overcome the cold-start challenge, offering a promising strategy for rapid, energy-efficient catalytic emission control.