Investigation of trimethylacetic acid adsorption on stoichiometric and oxygen-deficient CeO₂ (111) surfaces

Journal Article · Thu May 12 00:00:00 EDT 2016 · Physical Chemistry Chemical Physics. PCCP (Print)

DOI:https://doi.org/10.1039/C6CP00855K· OSTI ID:1329595

Sanghavi, Shail ^[1]; Wang, Weina ^[2]; Nandasiri, Manjula I. ^[1]; Karakoti, Ajay S. ^[3]; Wang, Wenliang ^[4]; Yang, Ping ^[5]; Thevuthasan, S. ^[1]

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1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shaanxi Normal Univ., Xi'an (China)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ahmedabad Univ. (India)
4. Shaanxi Normal Univ., Xi'an (China)
5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

We studied the interactions between the carboxylate anchoring group from trimethylacetic acid (TMAA) and CeO₂(111) surfaces as a function of oxygen stoichiometry using in situ X-ray photoelectron spectroscopy (XPS). The stoichiometric CeO₂(111) surface was obtained by annealing the thin film under 2.0 × 10^–5 Torr of oxygen at ~550 °C for 30 min. In order to reduce the CeO₂(111) surface, the thin film was annealed under ~5.0 × 10^–10 Torr vacuum conditions at 550 °C, 650 °C, 750 °C and 850 °C for 30 min to progressively increase the oxygen defect concentration on the surface. The saturated TMAA coverage on the CeO₂(111) surface determined from XPS elemental composition is found to increase with increasing oxygen defect concentration. This is attributed to the increase of under-coordinated cerium sites on the surface with the increase in the oxygen defect concentrations. Furthermore, XPS results were in agreement with periodic density functional theory (DFT) calculations and indicate a stronger binding between the carboxylate group from TMAA and the oxygen deficient CeO_2–δ(111) surface through dissociative adsorption.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1329595
• Report Number(s): LA-UR-16-20620; PPCPFQ
• Journal Information: Physical Chemistry Chemical Physics. PCCP (Print), Vol. 18, Issue 23; ISSN 1463-9076
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Inorganic and Physical Chemistry