In order to extend the dealloying systems and their electrocatalytic applications, in this work, electrocatalysis of ethanol in alkaline media on dealloyed Pd-Ni-P film is selected as a case study. Pd-Ni-P film is prepared via electro-deposition on Au substrate, and the dealloying process is carried out by repetitive potential cycling in acidic media to leach out most Ni and P components. The surface structural and electronic properties of the as-deposited film and the dealloyed film are characterized and compared using field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy. Surface roughening, Pd-segregation and electronic property variation upon dealloying are confirmed. Cyclic voltammetry and chronoamperometry on the two films in ethanol-containing alkaline media are used to assess their electrocatalytic performances, demonstrating significantly enhanced and durable ethanol oxidation on the dealloyed film. More importantly, in situ attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) is initially applied to explore the interfacial molecular information in the electrocatalysis on these two films to provide molecular insight into the enhanced electrocatalytic activity on the dealloyed film, revealing that the enhanced electrocatalysis correlates well with enhanced formation of both COad and acetate. (C) 2014 Elsevier Ltd. All rights reserved.