Evidencing Pt-Au alloyed domains on supported bimetallic nanoparticles using CO desorption kinetics

We explored here the possibility to use CO desorption kinetics monitored by IR spectroscopy as a tool to characterize the mixing of Au and Pt atoms at the surface of supported nanoparticles. CO desorption of CO monitored at 50 °C showed that a bimetallic sample exhibited an intermediate behavior between those of monometallic Au and Pt samples, reflecting the alloyed nature of the nanoparticles. Our data also show that alumina-supported Au nanoparticles led to the formation of surface carbonates at 50 °C, possibly formed through Boudouard reaction (2 CO → C + CO2), in contrast to the case of the Pt-based sample.