Plasmon assisted catalysis on Au nanoparticle-iron oxide nanocomposites

Irradiating metal nanoparticles with a laser at their plasmon resonance frequency generates immense plasmonic charge and high temperatures needed to drive catalytic processes. We report the plasmonically enhanced catalytic oxidation of CO. Fe2O3 is deposited on top of the Au nanoparticles by plasmon resonant chemical vapor deposition. The catalytic activity of the resulting Fe2O3-Au nanoparticle nanocomposites are studied by Raman spectroscopy and mass spectrometry. The catalytic activity is correlated with the surface enhanced Raman spectroscopy (SERS) intensity to serve as a measure of the enhanced electric fields from plasmonic excitation. The free CO molecules undergo a redox by the reaction, 2CO → C(s) + CO2. The free carbon atoms are found to condense in the cooler surrounding regions forming amorphous carbon and carbon nanotubes. We have carried out several control experiments demonstrating that these results are not possible with uniform heating, without plasmonic excitation.