摘要： a-Fe2O3/CaFe2O4 p-n heterojunctions were prepared via a simple in-situ hydrolysis process as highly ef?cient VOCs degradation photocatalyst, wherein no additional conditions such as high pressure, high temperature and surfactants were required. The structures and morphologies of the as-prepared samples were analyzed by XRD, SEM and TEM. The results revealed that a-Fe2O3/CaFe2O4 p-n heterojunctions exhibited superior photocatalytic activity of VOCs degradation compared to pure CaFe2O4 and a-Fe2O3 in both steady model and ?ow bed model. It can degrade more than 82% of acetaldehyde within 180 min in steady mode and 65% in ?ow mode under visible light irradiation. The prominent VOCs remove property could be attributed to the strong interfacial contact caused by the in-situ fabrication process and the promoted charge carrier separation ef?ciency due to the constructing of a-Fe2O3/CaFe2O4 p-n heterojunction. It provides some new insights into the design and fabrication of advanced photocatalytic materials with p-n heterojunction for high ef?ciency in VOCs photodegradation.