In English

Towards Plasmon-Enhanced Heterogeneous Catalysis on Metal Nanoparticles

Jenny Andersson
Göteborg : Chalmers tekniska högskola, 2014. 41 s.
[Examensarbete på avancerad nivå]

Heterogeneous catalysis is a vital part of the chemical industry. The energy e- ciency is, for many processes, somewhat less than desired. The main reason for this is high operating temperatures due to activation barriers. Research has shown that catalysts which also are plasmonically active yield higher reaction rates under illumination. It is theorised that hot electrons originating from the decay of plasmonic resonances assist in molecular dissociation via transient electron attachment. In reactions where dissociation is associated with the rate-limiting step, this could enhance the reaction rate at constant temperature. Plasmonic structures are characterised by build-ups in electric eld intensity in the vicinity of the structure, as well as elevated absorption eciencies (Qabs > 1). Due to the low energy e- ciencies of catalytic reactions, it is of interest to utilise plasmonic nanostructures to aquire new reaction pathways. A structure with a Au plasmonic nanoantenna, above which Pt catalytic particles are deposited, is proposed. The electric eld surrounding the Au nanoantenna would induce a polarisation in the catalytic particle, and hence, enhance the energetic charge carrier creation via locally enhanced absorption. The proposed structure is created using hole-mask colloidal lithography together with physical evaporation techniques. An experimental assembly is designed to test the structures. A signi cant increase in catalytic rate is observed under illumination of the sample, however, the e ect is not conclusively determined to be connected to the plasmonic nanoantennas since it is also observed during illumination of only the catalyst itself. This implies a direct optical excitation in the catalyst nanoparticle as the reason for the observed enhancement.

Nyckelord: Heterogeneous catalysis, LSPR, hydrogen oxidation, HCL

Publikationen registrerades 2015-01-26.

CPL ID: 211519

Detta är en tjänst från Chalmers bibliotek