This study explores leveraging the exceptional photothermal properties of carbon-based catalysts for enhanced tetracycline degradation via PMS activation. To minimize the impact of the high heat capacity of bulk water, we engineered a siphon-driven interfacial reactor that utilizes the photothermal effect to significantly enhance the efficiency of PMS activation. The increased temperature accelerates catalytic reactions, enabling the effective activation of peroxymonosulfate (PMS) to degrade pollutants through this thermal advantage. The photothermal-enhanced FeCo@BC demonstrates nearly 100% degradation efficiency of tetracycline within 15 min in differential batch mode. Further investigations, including quenching experiments and electron paramagnetic resonance tests, confirm that singlet oxygen (1O2) is the principal active species in the FeCo@BC/PMS system. This system also benefits from oxygen vacancies (Ov) that improve the adsorption and binding of PMS on FeCo@BC surfaces, aiding in the conversion of PMS into 1O2 and other radicals. In continuous operation mode, the interface photothermal reactor (IPR) achieved continuous tetracycline degradation, maintaining over 94% activity for 60 min.