Modulating the reactivity of Ni-containing Pt(111)-skin catalysts by density functional theory calculations

Hai-Yan Su; Xin-He Bao; Wei-Xue Li

doi:10.1063/1.2920174

Modulating the reactivity of Ni-containing Pt(111)-skin catalysts by density functional theory calculations

J Chem Phys. 2008 May 21;128(19):194707. doi: 10.1063/1.2920174.

Authors

Hai-Yan Su¹, Xin-He Bao, Wei-Xue Li

Affiliation

¹ State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.

PMID: 18500886
DOI: 10.1063/1.2920174

Abstract

We present here a first principles density functional theory investigation of the reactivity of Pt(111)-skin catalysts, which are varied from surface alloys with Ni to bulk PtxNi 1-x (x=0.25,0.50,0.75) alloys. Molecule (CO, O, and H) adsorption and oxidation of CO+O and H+O reactions were studied and analyzed in detail. Independent of the adsorbates, the interaction between adsorbates and substrates becomes weakened with increase in Ni, due to the downshift of d-band center of surface Pt atoms. Moreover, activation barriers of CO and H oxidation toward atomic oxygen gradually decrease. In term of CO preferential oxidation (PROX) in excess of hydrogen, it turns out that the overall reactivity and selectivity rely on the optimum of various elementary steps involved such as competitive molecular (dissociative) adsorption and oxidation reaction. The present calculations show that Pt3Ni(111) with Pt overlayer is an optimum catalyst for CO PROX in excess of hydrogen.