Katsiev, K;
Harrison, G;
Al-Salik, Y;
Thornton, G;
Idriss, H;
(2019)
Gold Cluster Coverage Effect on H2 Production over Rutile TiO2(110).
ACS Catalysis
, 9
(9)
pp. 8294-8305.
10.1021/acscatal.9b01890.
Preview |
Text
Thornton Katsiev et al ACS Catalysis revised no highlights.pdf - Accepted Version Download (1MB) | Preview |
Abstract
Unlike catalytic reactions thermally driven by metal nanoparticles, reaction rates in photocatalysis do not scale with either the density of nanoparticles or their size. Because of the complexity of multicomponent photocatalysts in powder form, this lack of correlation, routinely observed for decades, is still not understood. In order to explore this phenomenon, H2 production from ethanol over Au clusters with different coverages deposited on single-crystal rutile TiO2(110) were studied by scanning tunneling microscopy and online mass spectrometry. There is a nonlinear increase of the H2 production with increasing gold coverage. The key determining factor appears to be the Au intercluster distance. Increasing this distance resulted in an increase in the normalized production. These results are explained in terms of competition between clusters for excited electrons to reduce H+ (of surface OH groups) to H2. It was possible to determine the proportionality factor between the hydrogen production and the number of absorbed photons. A slope close to 1 is found, which is in line with the "current doubling effect" in electrocatalysis. Moreover, pump probe transient absorption spectroscopy measurements were conducted. The results show that excited electrons transfer from the conduction band of TiO2 to Au particles within the first picoseconds after UV excitation. The fact that Au metal intercluster distances directly affect the reaction rate indicates that there is an optimum arrangement between the metal and the semiconductor that could potentially be achieved by nanostructuring.
| Type: | Article |
|---|---|
| Title: | Gold Cluster Coverage Effect on H2 Production over Rutile TiO2(110) |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1021/acscatal.9b01890 |
| Publisher version: | https://doi.org/10.1021/acscatal.9b01890 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Gold clusters, photocatalytic hydrogen production, charge carrier diffusion length, current double effect, rutile TiO2(110) single crystal, reaction rate |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10081895 |
Archive Staff Only
 |
View Item |
