Article pubs.acs.org/JPCC
Catalytic Oxygen Activation on Helical Gold Nanowires Jianhui Yang,† Bo Li,† Qiuju Zhang,† Wai-leung Yim,‡ and Liang Chen*,† †
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, People's Republic of China ‡ Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632 S Supporting Information *
ABSTRACT: Oxygen activation on one-dimensional (1D) gold nanotube T(6,0) and nanowire W6-1 was investigated using first principles density functional methods (DFT). It is found that the oxygen adsorption strength on T(6,0) is unexpectedly weak, whereas W6-1 with inner Au−Au bonds is more active for O2 adsorption. To further promote the catalyzed oxygen activation, we proposed and evaluated two working strategies, including imposing a small strain along the axial direction and doping alien transition metal (TM) atoms. Specifically, 4% compression or doping Pt atoms can decrease the O2 dissociation barriers from 0.85 eV to a more desired 0.6 eV. The analysis of electronic structures and charge density difference revealed that the inner Au−TM bond can decrease the filling degree of the Au-dz2 orbital and, thus, improve the oxygen activity.
1. INTRODUCTION Since the pioneering work by Haruta, many studies have demonstrated that gold nanostructures (e.g., gold nanoparticles) are active to adsorb and dissociate O2 molecules.1−6 Thus, they can be applied as efficient catalysts in various oxidation reactions, such as partial oxidation,7 CO oxidation,3,8,9 and selective oxidation of styrene.1,10 Unfortunately, zero dimensional (0D) Au nanoparticles are very prone to sintering, so that they cannot be used as a long lifetime catalyst in practical applications. Recently, as the synthetic technology advances, various types of one-dimensional (1D) gold nanostructures have been successfully prepared.11−15 For example, helical gold nanowires (GNWs) were synthesized by rolling up Au(111) layers.13 Ultrathin GNWs with a diameter of
