Promoting formic acid oxidation performance of Pd nanoparticlesviaPt and Ru atom mediated surface engineering

The alteration of surface functional propertiesviaincorporation of foreign atoms is supposed to be a key strategy for the enhanced catalytic performance of noble-metal based nanocatalysts (NCs). In the present study, carbon-supported palladium (Pd)-based NCs including Pd, PdPt and PdRuPt have been preparedviaa polyol reduction method under the same reduction conditions as for formic acid oxidation reaction (FAOR) applications. By cross-referencing the results of the microscopic, spectroscopic and electrochemical analysis we demonstrated that adding a small amount of platinum (Pt) into Pd NCs (i.e.PdPt NCs) significantly promotes the FAOR performance as compared to that of Pd NCsviaweakening the CO^adsbond strength at a lower voltage (0.875 Vvs.NHE) than Pd (0.891 Vvs.NHE). Of special relevance, the PdPt NC shows a mass activity (MA) of 1.0 A mg⁻¹and 1.9 A mg⁻¹, respectively, in the anodic and cathodic scan. These values are ∼1.7-fold (0.6 A mg⁻¹) and ∼4.8-fold (0.4 A mg⁻¹) higher than those of Pd NC. Moreover, PdPt NC retains a higher MA (54 mA mg⁻¹) than that of Pd NC (9 mA mg⁻¹) after chronoamperometric (CA) stability tests over 2000 s. Meanwhile, further addition of ruthenium (Ru) (i.e.PdRuPt NCs) outstandingly enhances the CO tolerance during the CA testviaremoval of adsorbed CO^adsand thus shows the highest MA (62 mA mg⁻¹) after CA testing, which is higher than that of PdPt (54 mA mg⁻¹) and Pd (9 mA mg⁻¹) NCs. The intriguing results obtained in this study have great significance to provide further strategic opportunities for tuning the surface electronic properties of Pd-based NCs to design Pd-based NCs with improved electrochemical performance.