Metal oxide supported metal catalysts show promising catalytic performance in many industry-relevant reactions. However, the enhancement of performance is often limited by the insufficient metal/metal oxide interface. In this work, we demonstrate a general synthesis of Pt-early transition metal oxide (Pt-MO_x, M = Ti, Zr, V, and Y) catalysts with rich interfacial sites, which is based on the air-induced surface segregation and oxidation of M in the supported Pt-M alloy catalysts. Systematic characterizations verify the dynamic structural response of Pt-M alloy catalysts to air and the formation of Pt-MO_x catalysts with abundant interfacial sites. The prepared Pt-TiO_x interfacial catalysts exhibit improved performance in hydrogenation reactions of benzaldehyde, nitrobenzene, styrene, and furfural, as a result of the heterolytic dissociation of H₂ at Pt-metal oxide interfacial sites.