Size-controlled gold-palladium bimetallic alloy nanoparticles (NP) (1.8 nm, High Resolution-Transmission Electron Microscopy, HR-TEM) were prepared by a MVS (Metal Vapor Synthesis) technique. The Au-Pd NP were effectively immobilized by impregnation of a conductive porous carbon support (Vulcan XC-72) with the MVS-derived Au-Pd/acetone solution at 25°C. XRD and High Angle Annular Dark Field -STEM EDS analysis confirm alloy formation during the synthesis with an estimated average atomic ratio of 76 Pd wt. % and 24 Au wt. % and X-ray Adsorption Near Edge Spectroscopy (XANES) confirms that the Pd in the alloy exists as metallic Pd(0). Individually, both gold and palladium are active metals for the electroreduction of CO2 but they differ significantly in their adsorption energy for CO. This bimetallic catalyst was characterized and tested for the CO2RR in electrochemical cells and also in a complete electrolyzer cell. Various parameters were investigated including electrolysis cell potential, catalyst loading and Nafion ionomer content in the electrode. Careful analysis of the reduction products shows a selectivity of the CO2RR to CO of 100%. The faradaic efficiency (FE) for the CO2RR with respect to H2 evolution is influenced by the Nafion ionomer (I) content of the electrode. A FE of 90% for CO formation was obtained with an I/C ratio of 0.1. The catalyst was stable over prolonged testing with no deactivation during the electrolysis process over prolonged testing (> 6 hours).
Gold-palladium nanoparticle alloy catalyst for CO production from CO2 electroreduction
2018
Abstract
Size-controlled gold-palladium bimetallic alloy nanoparticles (NP) (1.8 nm, High Resolution-Transmission Electron Microscopy, HR-TEM) were prepared by a MVS (Metal Vapor Synthesis) technique. The Au-Pd NP were effectively immobilized by impregnation of a conductive porous carbon support (Vulcan XC-72) with the MVS-derived Au-Pd/acetone solution at 25°C. XRD and High Angle Annular Dark Field -STEM EDS analysis confirm alloy formation during the synthesis with an estimated average atomic ratio of 76 Pd wt. % and 24 Au wt. % and X-ray Adsorption Near Edge Spectroscopy (XANES) confirms that the Pd in the alloy exists as metallic Pd(0). Individually, both gold and palladium are active metals for the electroreduction of CO2 but they differ significantly in their adsorption energy for CO. This bimetallic catalyst was characterized and tested for the CO2RR in electrochemical cells and also in a complete electrolyzer cell. Various parameters were investigated including electrolysis cell potential, catalyst loading and Nafion ionomer content in the electrode. Careful analysis of the reduction products shows a selectivity of the CO2RR to CO of 100%. The faradaic efficiency (FE) for the CO2RR with respect to H2 evolution is influenced by the Nafion ionomer (I) content of the electrode. A FE of 90% for CO formation was obtained with an I/C ratio of 0.1. The catalyst was stable over prolonged testing with no deactivation during the electrolysis process over prolonged testing (> 6 hours).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
