Heterogenous Catalysis Mediated by Plasmon Heating
We introduce a new method for performing and miniaturizing many types of heterogeneous catalysis involving nanoparticles. The method makes use of the plasmon resonance present in nanoscale metal catalysts to provide the necessary heat of reaction when illuminated with a low-power laser. We demonstrate our approach by reforming a flowing, liquid mixture of ethanol and water over gold nanoparticle catalysts in a microfluidic channel. Plasmon heating of the nanoparticles provides not only the heat of reaction but the means to generate both water and ethanol vapor locally over the catalysts, which in turn allows the chip and the fluid lines to remain at room temperature. The measured products of the reaction, CO_2, CO, and H_2, are consistent with catalytic steam reforming of ethanol. The approach, which we refer to as plasmon-assisted catalysis, is general and can be used with a variety of endothermic catalytic processes involving nanoparticles.
Additional Information© 2009 American Chemical Society. Received August 19, 2009; Revised Manuscript Received October 16, 2009. Publication Date (Web): November 12, 2009. This work has been generously supported by the DARPA Center for Optofluidic Integration by Award Number HR0011-04-1-0032 and the Global Climate and Energy Program (GCEP), Stanford University. Supporting Information Available: SEM image of gold nanoparticles and optical absorbance of gold nanoparticles. This material is available free of charge via the Internet at http://pubs.acs.org.
Supplemental Material - nl902711n_si_001.pdf