We report a CeO2 incorporated cobalt oxide electrode with abundant nano-sized interfaces. The as-prepared heterostructures exhibit remarkable oxygen evolution reaction (OER) activity and excellent stability, surpassing the pristine cobalt oxide and the state-of-art RuO2. Further DFT calculations and experimental results indicate that the improved OER performance of CoO-CeO2 heterostructures originates from the hierarchically porous structure, large surface area and high electron density around Co sites. The armouphous phase is formed during OER test due to surface Ce leaching, which can further promoted the performance of the hybrids. This work elucidates the cooperative effects and in situ transformation of CeO2-incorporated cobalt oxide in water oxidation, providing a valuable guideline for designing electrocatalysts. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.