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SUMMARY:2017 Lord Lewis Lecture (I) Sustainable plasmonics: abundant mater
 ials for modular photocatalysis - Professor Naomi Halas\, RICE University
DTSTART:20170426T150000Z
DTEND:20170426T160000Z
UID:TALK67505@talks.cam.ac.uk
CONTACT:Sharon Connor
DESCRIPTION:Metallic nanoparticles\, used since antiquity to impart intens
 e and vibrant color into materials\, have more recently become a central t
 ool in the nanoscale manipulation of light. Metal nanoparticles can suppor
 t surface plasmons\, the collective oscillations of their conduction elect
 rons\, which give rise to their optical properties. In addition\, the nonr
 adiative decay of surface plasmons results in the generation of hot electr
 ons and holes within the metal\; charge transfer of these hot carriers bet
 ween the metal and adsorbate molecules can induce chemical transformations
 .  Since metallic nanoparticles provide direct optical excitation of surfa
 ce plasmons and the ability to tune the plasmon energies through control o
 f nanoparticle geometry\, they are ideal structures for the controlled gen
 eration of hot carriers for photocatalysis.  We have recently shown that r
 oom temperature dissociation of H2 at Au nanoparticle surfaces- an “impo
 ssible reaction”- can be driven by hot electron injection into the LUMO 
 level of the molecule. [1-3] In a device geometry where we were able to di
 stinguish between “hot” carriers due to plasmon decay and “cold” c
 arriers resulting from direct excitation of electrons\, we found that the 
 generation rate of hot carriers is proportional to the local electromagnet
 ic field within the plasmon-excited metal.[4]   We have applied this disco
 very to design a new type of photocatalyst using a modular approach\, comb
 ining a metallic nanoparticle with a good plasmonic response as an “ante
 nna”\, coupled to a catalytically active but poorly optically absorbing 
 metal nanoparticle\, as a “reactor”\, situated within the antenna nano
 particle’s fringing field.[5]  One highly promising candidate for the an
 tenna in this modular design is Aluminum\, the most abundant metal on eart
 h. We will show how this “antenna-reactor” concept can be realized to 
 control the reactivity of the catalytic “reactor” particle\, as well a
 s  control the selectivity of chemical reaction outcomes. \n\n[1] S. Mukhe
 rjee et al.\, Nano Letters 13\, 240-247 (2012).\n[2] S. Mukherjee\, et al.
 \, Journal of the American Chemical Society 136\, pp 64–67 (2014).\n[3] 
 L. Zhou et al.\, Nano Letters 16\, 1478-1484 (2016).\n[4] B. Y. Zheng et a
 l.\, Nature Communications 6\, 7797 (2015). \n[5] D. F. Swearer et al.\, P
 NAS 113\,  8916–8920 (2016).\n
LOCATION:Wolfson Lecture Theatre\,  Department of Chemistry
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