Synergistic Combination of Plasma Sputtered Pd-Au Bimetallic Nanoparticles for Catalytic Methane Combustion

Pd-Au bimetallic nanoparticles supported by silicon carbide have been prepared by plasma sputtering deposition and employed as the catalyst for methane combustion. It is found that the bimetallic nanoparticles consist of tightly-coupled Pd and Au particles, which are neither Pd-Au alloyed nor core-shell structured. The catalytic activity increases with the Pd loading in the catalysts. When the temperature is higher than 520 degrees C, Pd catalysts have an obvious drop in the catalytic activity due to the decomposition of PdO. However, the introduction of Au can delay and weaken the drop. It is indicated that there exists a synergistic combination between Pd and Au: oxygen transfers from Pd to Au at a temperature lower than 520 degrees C and from Au to Pd at higher temperature. Transmission electron microscopy and X-ray photoelectron spectroscopy results further confirm the synergistic combination.