CFN Colloquium

"Darkening Pt Nanocrystals for Photocatalysis"

Presented by Yugang Sun, Department of Chemistry, Temple University

Thursday, April 27, 2017, 4:00 pm — CFN Bldg 735, Seminar Room, 2nd Floor

Platinum (Pt) nanocrystals are commonly used in chemical reactions because of their unusual catalytic activity, for example, photocatalytic water splitting of water. In a typical design, Pt nanocrystals can accept photo-excited electrons from light absorbers such as semiconductor quantum dots (QDs) to catalyze hydrogen evolution reaction (HER) [1]. Charge transfer from QDs to Pt nanocrystals is very inefficient, and shuttle molecules (e.g., methyl viologen) or other shuttle species are necessary to facilitate the charge transfer [2]. In addition to receiving energetic electrons from semiconductor QDs, Pt nanocrystal can also absorb visible light to generate energetic electrons (or hot electrons), which can directly reduce reactive species or migrate across a metal/semiconductor Schottky barrier to the conduction band of a semiconductor. Different from the widely studied plasmonic metal nanocrystals (e.g., Au, Ag), the efficiency of generating hot electrons in the weakly absorbing Pt nanocrystals is very low. We found that depositing Pt nanocrystals on spherical glass beads (i.e., SiO2 particles) could significantly enhance the visible absorption coefficient of the Pt nanocrystals. For example, in SiO2@Pt nanocrystals@TiO2 core-shell nanostructures, the enhancement in visible absorption enables the efficient generation of energetic electrons in photoexcited Pt nanocrystals, which can easily transfer to the TiO2 surface layer to drive HER and many other chemical reactions [3].

Hosted by: Fang Lu

12097  |  INT/EXT  |  Events Calendar


Not all computers/devices will add this event to your calendar automatically.

A calendar event file named "calendar.ics" will be placed in your downloads location. Depending on how your device/computer is configured, you may have to locate this file and double click on it to add the event to your calendar.

Event dates, times, and locations are subject to change. Event details will not be updated automatically once you add this event to your own calendar. Check the Lab's Events Calendar to ensure that you have the latest event information.