Adsorbed oxygen-induced cluster reconstruction on core–shell Ni@Pt and Pt clusters

• Core–shell Ni@Pt cluster is proposed as a prospective candidate for DOC.
• The strength of Pt–O bonds on 1 nm Ni@Pt is weaker than pure Pt clusters.
• First nearest-neighbor (1NN) method is employed to analyze cluster reconstruction.
• 1NN Pt–Pt bond distribution from DFT results is qualitatively comparable to EXAFS data.
• The amplitude of 1NN Pt–Pt bond distribution is decreasing in the presence of oxygen.

Density-functional calculations were performed to study Pt–O bonding interaction on core–shell Ni@Pt and pure Pt clusters composed of 55 atoms each. Based on oxygen adsorption energy and ν(Pt–O) stretching frequency, the global trend of Pt–O bonding strength in the clusters accommodates the successive order of bridge (and/or hcp-like) > fcc-like > vertex site. Further analysis on oxygen-induced reconstruction effect using first nearest neighbor (1NN) analysis shows that 1NN Pt–Pt distribution pattern of surface atoms changes abruptly after oxygen adsorbed. The profiles of distorted 1NN distribution pattern are greatly determined by the position and the number of adsorbed oxygen on the clusters including whether the cluster type is core–shell or not. The broadening distribution pattern clearly indicates deviation of Pt–Pt bond length due to Pt–O bonds formation and the general trend is similar with the one observed in platinum-related spectroscopy studies.

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