Figure 1

(a) Configurations of two chemisorbed ${\mathrm{O}}_2$ molecular precursors at the bridge site and fcc hollow site. (b) Molecular orbital energy diagram for ${\mathrm{O}}_2$.Reuse & Permissions

Figure 2

Charge/spin-charge difference density $\Delta \rho /\Delta {\rho }_{\sigma }$ along the surface normal direction $z$ for ${\mathrm{O}}_2^{*}$ at bridge (a) and fcc hollow (b) site on Pt (111) surface. Black squares/circles stand for the $z$-coordinates of Pt/oxygen atoms, and vertical dash lines stand for the middle position between the highest Pt and the lowest O atoms. The isosurfaces of $\Delta {\rho }_{\uparrow }$ and $\Delta {\rho }_{\downarrow }$ are plotted inside each subfigure using XCrySDen [23], where light and dark color means positive and negative change, respectively. The isovalues for all the isosurfaces are $\pm 0.04e{\AA }^{-3}$.Reuse & Permissions

Figure 3

Projected DOS of ${\mathrm{O}}_2^{*}$ at bridge (a) and fcc hollow (b) sites on Pt (111) surface. Fermi energy is zero and spin-down states are plotted as negative. Isosurfaces of the real part of Bloch eigenfunctions $\mathrm{Re}({\psi }_{n\overrightarrow{k}})$ at $\overrightarrow{k}=[\frac{1}{8}\frac{1}{8}0]$ of the first Brillouin zone are plotted for certain unoccupied peaks, as labeled in each subfigure. The absolute isovalues for all the isosurfaces are $\frac{1}{3}$ of the maximum absolute values of $\mathrm{Re}({\psi }_{n\overrightarrow{k}})$ and light (dark) color means a positive (negative) value. For bridge-site case (a), the isosurfaces of ${\psi }_1$ ($n=90$, $ϵ=0.54\mathrm{eV}$) and ${\psi }_3$ ($n=89$, $ϵ=0.65\mathrm{eV}$) behave as spin-up and -down ${\pi }_{\perp }^{\star }$, respectively, while spin-down ${\psi }_2$ ($n=90$, $ϵ=0.32\mathrm{eV}$) has the shape of ${\pi }_{\parallel }^{\star }$. For fcc-site case (b), isosurface of ${\psi }_1/{\psi }_3$ ($n=89$, $ϵ=0.35\mathrm{eV}$) behaves as spin-up/down ${\pi }_{\parallel }^{\star }$, while ${\psi }_2/{\psi }_4$ ($n=90$, $ϵ=0.52\mathrm{eV}$) is similar to spin-up/down ${\pi }_{\perp }^{\star }$.Reuse & Permissions

Figure 4

Electron transfer $\Delta N$ and induced dipole $P_z$ of ${\mathrm{O}}_2^{*}$ at bridge site versus (111) surface work function of different metals. The bond length of ${\mathrm{O}}_2^{*}$ and its distance to the top surface layer are fixed as the optimized values on Pt(111).Reuse & Permissions