Tunable amount of monatomic and nanoscale Pt clusters were trapped in TiO2 and CeO2 nanowires via a generic one-step dealloying approach from designed Al-Ti-Pt and Al-Ce-Pt precursor alloys. It was demonstrated that the doped Pt were in the form of both single atoms and Pt clusters stabilized in TiO2 or CeO2 nanowires. Electrochemical tests manifested that these highly dispersed Pt doped metal oxide greatly enhanced the utilization efficiency of noble metals. When used as an electrocatalyst for the methanol oxidation reaction (MOR) or hydrogen evolution reaction (HER), the Pt-TiO2 or Pt-CeO2 catalysts after activation exhibited much higher catalytic activity and stability as compared to the commercial Pt/C catalyst. The highest mass activity of the Pt0.2-TiO2 catalysts obtained from dealloying Al85Ti14.8Pt0.2 reached 1200 mA mg−1 for MOR, more than six times higher than that of Pt/C. The mass activity of the Pt0.2-CeO2 for HER is around 50 times that of Pt/C. With clear advantages of low costs, simple fabrication procedure, and enhanced catalytic performance, these Pt-metal oxide nanowires can be suitable for many catalytic reactions. •A general top-down dealloying strategy is developed to stabilize single Pt atoms and clusters in TiO2 and CeO2 nanowires.•After activation, the Pt-doped TiO2 exhibit much enhanced mass activity for methanol electro-oxidation.•Due to the stabilization effect of metal oxides, the Pt-doped catalysts are highly stable for electrocatalysis.