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Title: Electron injection study of photoexcitation effects on supported subnanometer Pt clusters for CO 2 photoreduction

In this paper, using density functional theory, we study the effect of injected electrons (simulating photoexcited electrons) on the energetics, structures, and binding sites available to CO 2 molecules on subnanometer Pt clusters decorated onto anatase TiO 2(101) surfaces, shedding light on the first and key step of CO 2 photoreduction. Upon the addition of one, two, or three electrons, the O–C–O angles of adsorbed CO 2 become progressively smaller in binding sites that directly contact Pt clusters, while no significant change is found in the intra bond length of the adsorbed CO 2 and in the bonding distances between the adsorbed CO 2 and supported clusters. The extra electrons lead to the stabilization of adsorption sites identified on neutral slabs, including previously metastable configurations, suggesting the enhancement of accessible CO 2 binding sites. Furthermore, supported clusters are able to populate the electronic states of adsorbed CO 2 species, facilitating the formation of the CO 2 - anion. To help interpret experimentally observed frequencies, conversion factors are proposed to gain insight into the charge state and O–C–O angle of the adsorbed CO 2. Interestingly, upon electron addition, cluster reconstruction may exist due to the bonding inclination between CO 2 andmore » atoms in the Pt cluster, further stabilizing the intermediate complexes. In conclusion, the rate-limiting step (C–O bond cleavage) in the CO 2 dissociation to CO is slightly reduced by the introduction of an extra electron. Our results show that subnanometer metal cluster based photocatalysts are good candidates for CO 2 photoreduction.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1] ; ORCiD logo [1]
  1. Univ. of South Florida, Tampa, FL (United States). Dept. of Chemical and Biomedical Engineering
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Materials Science Division
Publication Date:
Report Number(s):
LLNL-JRNL-745700
Journal ID: ISSN 1463-9076; 900486
Grant/Contract Number:
AC52-07NA27344; CHE-1531590
Type:
Accepted Manuscript
Journal Name:
Physical Chemistry Chemical Physics. PCCP (Print)
Additional Journal Information:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 20; Journal Issue: 23; Journal ID: ISSN 1463-9076
Publisher:
Royal Society of Chemistry
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of South Florida, Tampa, FL (United States)
Sponsoring Org:
USDOE; LLNL Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS
OSTI Identifier:
1465295
Alternate Identifier(s):
OSTI ID: 1439755