| 저자(한글) |
Hu, S.,Munoz, F.,Noborikawa, J.,Haan, J.,Scudiero, L.,Ha, S. |
| 초록 |
The electronic structure and electrochemical performance of carbon supported Pd-based bi- and trimetallic nanoparticles are investigated. Pd/C, PdNi/C, PdCu/C, and PdNiCu/C alloys with face centered cubic crystal structure are synthesized by the one-step salt reduction method. The activities for these alloys toward the formic acid electrochemical oxidation measured by cyclic voltammetry (CV) display significant current density increase compared to that of Pd/C. An improvement in activity by a factor of 2 and 4 is measured when the data is normalized by electrochemical surface area (ECSA) and by Pd mass, respectively. A downward shift of the averaged d-band center relative to the Fermi level is observed for Pd-based alloys compared to Pd/C by X-ray photoelectron spectroscopy (XPS) measurements. The relationship between activity and the average d-band center displays a volcano shape for these alloys. Among the samples that we prepared for this study, PdNiCu/C alloy shows the best activity with the d-band center of 2.64+/-0.10eV. From CO stripping measurements the PdCu/C and PdNiCu/C alloys show less CO adsorption than Pd/C with PdCu/C showing the best stability toward the formic acid electrochemical oxidation. |
