Enhanced CO tolerance of Pt clusters supported on graphene with lattice vacancies

Yuji Hamamoto,Ikutaro Hamada,Frank Abild-Pedersen,Kouji Inagaki,Thomas Bligaard,Yoshitada Morikawa,Sasfan Arman Wella

doi:10.1103/physrevb.102.075408

Abstract

The adsorption of CO on ${\mathrm{Pt}}_{4}$ clusters supported on graphene with lattice vacancies is studied theoretically using the first-principles calculation. Our results show that the electronic structure of the graphene-supported ${\mathrm{Pt}}_{4}$ clusters is significantly modified by the interaction with carbon dangling bonds. As a result the adsorption energy of CO at a Pt site decreases almost linearly with the lowering of the Pt $d$-band center, in analogy with the linear law previously reported for CO adsorption on various Pt surfaces. An exceptional behavior is found for ${\mathrm{Pt}}_{4}$ supported on graphene with a tetravacancy, where CO adsorption is noticeably weaker than predicted by the shift in the $d$-band center. Detailed electronic structure analyses reveal that the deviation from the linear scaling can be attributed to lack of Pt $d$ states near the Fermi level that hybridize with CO molecular orbitals. The weakening of CO adsorption on the ${\mathrm{Pt}}_{4}$ clusters is considered as a manifestation of the support effect of graphene, and leads to the enhancement of CO poisoning tolerance that is crucial for developing high-performance Pt cluster catalysts.

Highlights

The extraordinary electronic and structural properties of graphene hold considerable potential for a wide variety of industrial applications
Detailed electronic structure analyses reveal that the deviation from the linear scaling can be attributed to lack of Pt d states near the Fermi level that hybridize with carbon monoxide (CO) molecular orbitals
We have investigated theoretically CO adsorption on Pt4 clusters supported on graphene with lattice vacancies

Summary

Introduction

The extraordinary electronic and structural properties of graphene hold considerable potential for a wide variety of industrial applications. One of the most promising candidates is the application of graphene as a support material for metal nanoparticle catalysts. A great number of experiments have been carried out in the last decade (see reviews [1,2,3,4,5,6,7,8,9,10,11] and references therein) and it has been demonstrated that Pt supported on graphene exhibits improved catalytic activity [12], durability [13], and carbon monoxide (CO) tolerance [12] as compared with on carbon black.

Methods

Results

Conclusion