Selective hydrogenation of cinnamic acid was studied over different supported NiCoB amorphous alloys; a γ-Al₂O₃ supported NiCoB catalyst showed particularly good activity. The application of ultrasound during catalyst preparation was found to make the Ni active sites more dispersed, thus enhancing the catalyst activity. The NiCoB/γ-Al₂O₃-u catalyst so obtained could be recycled effectively for nine runs in tert-butanol, in contrast it deactivated after only three runs in water. XPS, SEM and XRD characterizations indicated that loss of Ni and hydration of the γ-Al₂O₃ support were the main reasons for catalyst deactivation in water. Thus, an efficient and stable catalytic system involving NiCoB/γ-Al₂O₃-u and tert-butanol was established for cinnamic acid hydrogenation in this study.