In this work, CeO 2 /Co 3 O 4 microflowers have been prepared by a facile bimetallic metal-organic framework (MOF) derivatization method. By optimizing the calcination temperature, the CeO 2 /Co 3 O 4 -350 with the calcination temperature as 350 ℃ has been prepared with the optimal morphology and gas sensing performance. The microflowers composed of nanosheet subunits can fully expose the surface-active sites of CeO 2 /Co 3 O 4 -350, expanding its contact surface with the detected gas. Moreover, for the larger atomic radius and polyvalent state of Ce, more oxygen vacancies can be generated on the surface of CeO 2 /Co 3 O 4 -350 composites. And the p-n heterojunction formed at the junction of CeO 2 and Co 3 O 4 can expand the depletion layer at the interfaces, increasing the amount of adsorbed oxygen, which conduce to heighten the response of CeO 2 /Co 3 O 4 -350. Benefiting from the synergy of oxygen vacancy and p-n heterojunction, CeO 2 /Co 3 O 4 -350 exhibits excellent sensing properties toward n-butanol. At the operating temperature of 190°C, CeO 2 /Co 3 O 4 -350 can make a fast response/recovery (63 s/11 s) to 100 ppm n-butanol with a response value of 87.96, and the lowest limit (LOD) of detection is 2 ppm. Moreover, the theoretical detection limit of CeO 2 /Co 3 O 4 -350 to n-butanol has been evaluated to be 105 ppm, which means that it can respond to ppb-level n-butanol. After 15 days long-term test, the response still maintains about 94%, showing good stability of CeO 2 /Co 3 O 4 -350, which is of great significance to the practical application of gas sensors. Our work uses simple MOF-derived method to construct sensing materials with larger active surface and optimized internal electronic structure, providing a facile and practical strategy to design gas sensing materials. • Bimetallic MOF-derived CeO 2 /Co 3 O 4 microflowers with p-n heterojunction and rich oxygen vacancy were synthesized. • The CeO 2 /Co 3 O 4 sensor with high-performance n-butanol response can be obtained by optimizing calcination temperature. • The excellent sensing performance of CeO 2 /Co 3 O 4 is attributed to the synergy between oxygen vacancy and p-n heterojunction.