Theoretical Study of Hydrogen Adsorption on Au@Pd Icosahedral Nanoparticle

SANDOVAL, M. G.; LUNA, R.; BRIZUELA, G.; PEREIRA, ALINE O.; MIRANDA, C. R.; JASEN, P.

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2017 vol. 121 p. 8613 - 8622

1932-7447

<!-- /* Font Definitions */@font-face{font-family:"ＭＳ 明朝";mso-font-charset:78;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:1 134676480 16 0 131072 0;}@font-face{font-family:"ＭＳ 明朝";mso-font-charset:78;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:1 134676480 16 0 131072 0;}@font-face{font-family:Cambria;panose-1:2 4 5 3 5 4 6 3 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536870145 1073743103 0 0 415 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:Cambria;mso-fareast-font-family:"ＭＳ 明朝";mso-bidi-font-family:"Times New Roman";}p.MsoPlainText, li.MsoPlainText, div.MsoPlainText{mso-style-priority:99;mso-style-link:"Plain Text Char";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:10.5pt;font-family:Courier;mso-fareast-font-family:"ＭＳ 明朝";mso-bidi-font-family:"Times New Roman";}span.PlainTextChar{mso-style-name:"Plain Text Char";mso-style-priority:99;mso-style-unhide:no;mso-style-locked:yes;mso-style-link:"Plain Text";mso-ansi-font-size:10.5pt;mso-bidi-font-size:10.5pt;font-family:Courier;mso-ascii-font-family:Courier;mso-hansi-font-family:Courier;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:10.0pt;mso-ansi-font-size:10.0pt;mso-bidi-font-size:10.0pt;font-family:Cambria;mso-ascii-font-family:Cambria;mso-fareast-font-family:"ＭＳ 明朝";mso-hansi-font-family:Cambria;}@page WordSection1{size:612.0pt 792.0pt;margin:72.0pt 90.0pt 72.0pt 90.0pt;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->First-principles calculations based on the densityfunctional theory (DFT) were applied to study the H2 adsorption onAu@Pd NP (core@shell icosahedral bimetallic nanoparticle). The calculationsindicate that, for almost all adsorption sites, there is no energy barrier forH2 dissociation at the surface of Au@Pd NP, and the H2molecule spontaneously dissociate. The only exceptions are the case of atopfrom edge (AE) and atop from vertex (AV) sites, where there are no-dissociationat all. Looking at the adsorption energies, dissociated cases are 1.3 eV morestable than non-dissociated cases. The work function (WF) values associated toNP with H2 adsorbed are lower than the obtained in the case ofPd/Au(111) surface. When H2 is dissociated on the NP or surface theWF increases while in the non dissociated case decrease. We also considered thechanges in hydrogen adsorption and dissociation in mixed shell NP structures.The atomic H penetration was also studied for Au@Pd NP.   Hydrogen adsorptionon both, Au@Pd NP and Pd/Au(111) surface, systems lead to slight shift of Pd´sd states to lower energies, while the s and p states are almost unaffected. Ahigher hybridization between Pd and H is detected in the NP case. Each H atomof the H2 molecule adsorbed on the NP becomes negatively charged.Seem that the charge transference occurs toward the NP. The bond order onorbital population analysis indicates no bond for H-H and a decrease in themetal-metal bond while a Pd-H bond is formed.