Abstract
In this study, the impact of supported Pt particles on the thermal and photocatalytic activity of well-defined anatase TiO2 (A-TiO2) nanocrystals (NCs) was investigated. Pt-decorated NCs were characterized using scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The activity of the Pt-decorated NCs for the thermal and photocatalytic reactions of acetaldehyde was then studied using temperature-programmed desorption in ultrahigh vacuum. The bare TiO2 NCs demonstrated thermal activity primarily for aldol condensation, partial oxidation, and reductive coupling pathways. For the Pt-decorated NCs, the Pt deposits were found to act mainly as a site blocker for the thermal aldol condensation and partial oxidation pathways, as well as acting as recombination centers for photogenerated electrons and holes at the surface, suppressing the photocatalytic activity of the NCs. Upon pretreating with O2, however, the photocatalytic activity of the Pt-decorated NCs was restored, indicating that oxygen adsorbed at the Pt reacts with the photogenerated conduction band electrons captured by the Pt deposits, preventing their recombination with photogenerated holes at the surface. These results demonstrate how the dynamics of the photogenerated charge carriers may be influenced both by the presence of Pt deposits and adsorbates at the surface of a photocatalyst.
| Original language | English |
|---|---|
| Pages (from-to) | 10477-10486 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry C |
| Volume | 123 |
| Issue number | 16 |
| DOIs | |
| State | Published - Apr 25 2019 |
| Externally published | Yes |
Funding
Funding for this study was primarily provided by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Grant DEFG02-04ER15605. Sample synthesis discussed here was supported as part of the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001004. Partial funding support for this study was also provided by the Vagelos Institute of Energy Science and Technology at the University of Pennsylvania. Additionally, P.A.P. would like to acknowledge the Vagelos Institute of Energy Science and Technology at the University of Pennsylvania for a graduate fellowship.
| Funders | Funder number |
|---|---|
| Catalysis Center for Energy Innovation | DE-SC0001004 |
| Vagelos Institute of Energy Science and Technology | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | DEFG02-04ER15605 |
| University of Pennsylvania |