Theoretical study of the oxygen adsorption energy for the supported Pt cluster, focused on the electronic metal-support interaction

Abstract

This study analyzed the icosahedral Pt55 cluster on the surface of La2O3 by density functional theory (DFT) calculations. The oxygen adsorption energy (ΔE) for the supported Pt55 cluster was different from the ΔE value for the Pt55 cluster without oxide supports. Moreover, the ΔE values for the supported Pt55 cluster depend on adsorption sites. This study applied the idea of Electronic Metal-Support Interaction (EMSI), and proposed the concept of “effective chemical potential (μeff)”. According to DFT calculation, the μeff values of supported Pt55 cluster were the intermediate values between the chemical potential values of Pt55 without oxide support (μPt55) and La2O3 (μLa2O3) (i.e. μPt55<μeff<μLa2O3). Finally, this study proposes a method to predict ΔE values for the supported Pt cluster. The ΔE value can be estimated by substituting predicted μeff value into a mathematical formula that combines the Hard-Soft-Acid-Base (HSAB) concept and d-band center theory. The proposed method requires μPt55, μLa2O3 and d-band center values of the Pt55 cluster without oxide support, but do not require any DFT results of the supported Pt55 cluster. Comprehensibly, the proposed method can predict ΔE values from basic physical quantities.