A DFT study of phenol adsorption on a low doping Mn-Ce composite oxide model

ORIANA D'ALESSANDRO; DELFINA GARCÍA PINTOS; ALFREDO JUAN; BEATRIZ L. IRIGOYEN; JORGE SAMBETH

APPLIED SURFACE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 359 p. 14 - 20

0169-4332

Density functional theory calculations (DFT + U) were performed on a low doping Mn?Ce composite oxide prepared from experimental data, including X-ray diffraction (XRD) and temperature-programmed reduction (TPR). We considered a 12.5% Mn-doped CeO2 solid solution with fluorite-type structure, where Mn replaces Ce4+ leading to an oxygen-deficient bulk structure. Then, we modeled the adsorption of phenol on the bare Ce0.875Mn0.125O1.9375(1 1 1) surface. We also studied the effect of water adsorption and dissociation on phenol adsorption on this surface, and compared the predictions of DFT + U calculations with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements. The experimental results allowed us to both build a realistic model of the low doping Mn-Ce composite oxide and support the prediction that phenol is adsorbed as a phenoxy group with a tilt angle of about 70◦ with respect to the surface.<!-- /* Font Definitions */@font-face{font-family:Arial;panose-1:2 11 6 4 2 2 2 2 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-parent:"";margin:0in;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;mso-bidi-font-size:10.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language:ES;}@page Section1{size:8.5in 11.0in;margin:1.0in 1.25in 1.0in 1.25in;mso-header-margin:.5in;mso-footer-margin:.5in;mso-paper-source:0;}div.Section1{page:Section1;}-->Density functional theory calculations (DFT+U) wereperformed on a low doping Mn?Ce composite oxide prepared from experimentaldata, including X-ray diffraction (XRD) and temperature-programmed reduction (TPR).We considered a 12.5% Mn?doped CeO2 solid solution with fluorite?typestructure, where Mn replaces Ce4+ leading to an oxygen?deficientbulk structure. Then, we modeled the adsorption of phenol on the bare Ce0.875Mn0.125O1.9375(111) surface. We alsostudied the effect of water adsorption and dissociation on phenol adsorption onthis surface, and compared the predictions of DFT+U calculations with diffusereflectance infrared Fourier transform spectroscopy (DRIFTS) measurements. Theexperimental results allowed us to both build a realistic model of the low doping Mn?Ce composite oxide andsupport the prediction that phenol is adsorbed as a phenoxy group with a tiltangle of about 70° with respect to the surface.