Promoting formic acid oxidation performance of Pd nanoparticles via Pt and Ru atom mediated surface engineering |
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| Authors: | Dinesh Bhalothia Tzu-Hsi Huang Pai-Hung Chou Kuan-Wen Wang Tsan-Yao Chen |
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| Affiliation: | Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013 Taiwan, +886-3-5715131 ext. 34271 ; Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 10608 Taiwan ; Hierarchical Green-Energy Materials (Hi-GEM) Research Centre, National Cheng Kung University, Tainan 70101 Taiwan |
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| Abstract: | The alteration of surface functional properties via incorporation 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 prepared via a 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 NCs via weakening the COads bond strength at a lower voltage (0.875 V vs. NHE) than Pd (0.891 V vs. NHE). Of special relevance, the PdPt NC shows a mass activity (MA) of 1.0 A mg−1 and 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 test via removal of adsorbed COads and 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.Pt atoms attract electrons from neighboring atoms. Ru atoms attract hydroxide ligands. These two characteristics respectively weaken the bonding and recovering of the Pt site from CO oxidation and then facilitate the FAO in ternary PdPtRu NCs. |
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