Hydrolytic dehydrogenation of ammonia borane (AB) has attracted much attention due to its high hydrogen content and stability. Therefore, the design and construction of low-cost and high-performance catalysts for AB hydrolysis are of great significance. In this work, Co/CoFeO x -X (X is the additional content of Fe precursor) bimetallic oxide nanofilms having an amorphous structure were prepared on an (IL)/water interface for the hydrolysis of AB. Strategies including the rapid addition of metal precursors and variation of Co/Fe atom ratios were employed to induce an amorphous structure for inhibiting the rearrangement of the formed metal nuclei and optimizing the alloying effect on the IL/water interface. This ultrathin amorphous nanofilm structure can expose more metal active sites. Moreover, the electronic interaction between Fe and Co after doping Fe into the Co/CoO x nanofilms facilitates the adsorption and activation for AB and H 2 O molecules. As a result, the optimized Co/CoFeO x -25 catalyst exhibits excellent catalytic activity with a turnover frequency (TOF) value of 12.25 mol H2 ·mol Co –1·min–1, which is considerably higher than that of the monometallic Co/CoO x catalyst. This enhanced activity can be ascribed to the morphology advantages and the electronic effect of Fe and Co on the Co/CoFeO x -25 catalyst. This work provides a promising method to design the highly efficient non-noble metal catalysts for the hydrolysis of chemical hydrides. [Display omitted] • Co/CoFeO x -X composite oxide nanofilms were constructed via the method of (IL)/water interface. • The Co/CoFeO x -25 exhibits superior catalytic activity for AB hydrolysis with TOF of 12.25 mol H2 ·mol Co –1·min–1 without NaOH. • The electronic effect of CoFeO x composite oxides facilitate the adsorption and activation of AB and H 2 O molecules. • An amorphous structure of Co/CoFeO x -25 is in a metastable state, which provides abundant defects and active sites. [ABSTRACT FROM AUTHOR]