Deactivation of an
anode catalyst resulting from the
poisoning of
COad-like intermediates is one of the major problems for
methanol and
ethanol electro-oxidation reactions (MOR & EOR), and remains a grand challenge towards achieving high performance for direct alcohol fuel cells (DAFCs). Herein, we report a new approach for the preparation of ultrafine
cobalt-doped CeO2 dots (Co-CeO2, d = 3.6 nm), which can be an effective anti-
poisoning promoter for Pd catalysts towards MOR and EOR in alkaline media. Compared to Pd/CeO2 and pure Pd, the hybrid Pd/Co-CeO2 nanocomposite catalyst exhibited a much enhanced activity and remarkable anti-
poisoning ability for both MOR and EOR. The nanocomposite catalyst showed much higher mass activity (4×) than a state-of-the-art PtRu catalyst. The promotional mechanism was elucidated using extensive characterization and density-functional theory (DFT). A bifunctional effect of the Co-CeO2 dots was discovered to be due to (i) an enhanced electronic interaction between Co-CeO2 and Pd dots and (ii) the increased
oxygen storage capacity of Co-CeO2 dots to facilitate the oxidation of
COad. Therefore, the Pd/Co-CeO2 nanocomposite appears to be a promising catalyst for advanced DAFCs with low cost and high performance.