Beyond the Gold–Hydrogen Analogy: Doping Gold Cluster with H-atom–O₂ Activation and Reduction of the Reaction Barrier for CO Oxidation

Abstract

The gold–hydrogen analogy is well established in terms of analogous chemistry exhibited by gold and hydrogen atoms. A step beyond this analogy is demonstrated here by showing that the replacement of a Au atom with a H-atom in a gold cluster can lead to considerable enhancement in its reactivity. The present computational study reveals that while the closed-shell neutral pristine gold cluster Au8 can bind only weakly with an O2 molecule, its doped counterpart Au7H shows remarkable enhancement in its binding with molecular oxygen. It also shows an increment in O–O bond length and a red shift in vibrational frequency, indicating the activation of the O2 molecule. Furthermore, the H-doped gold cluster reduces the barrier height for the environmentally important CO oxidation reaction as compared to the pristine cluster. These observations may spur further studies in the design of a cost-effective and efficient catalyst by doping gold clusters with a cheaper element like hydrogen.

Reactions involving some gas molecules through sequestration on Al12Be cluster: An electron density based study

“…To this end, it might be worthwhile to qualitatively compare the activation energy barrier ( ‡ ) computationally predicted by various research groups with our obtained results (notwithstanding the fact that various different levels of DFT theory have been used by different research groups). Ghosh and coworkers reported ‡ values of 1.13 eV and 0.7 eV for the cases of CO oxidation on Au 8 and Au 7 H clusters, respectively . On the other hand, Pal and coworkers reported ‡ values of 0.48, 0.76, and 0.57 eV for the cases of CO oxidation reaction on Au 7 , Au 6 Si, and Au 7 Si clusters, respectively .…”

“…All the thermodynamic as well as kinetic results have been accordingly presented. It has been demonstrated in the literature that by following DFT approaches, qualitatively correct energetics for the CO oxidation reaction could be obtained. In Table , we have presented the thermochemical results for the co‐adsorption process.…”

“…It has been pointed out by Grimme et al that wb97xd functional performs well in a wide range of problems . To study the CO oxidation reaction, a Langmuir–Hinshelwood type of mechanism has been followed where the co‐adsorbed (on Al 12 Be) CO and molecular O 2 have been considered as the starting point (reactant) . We have followed the procedure outlined in Ref.…”

Noble‐Metal‐Free Single‐Atom Catalysts CuAl4O7–9− for CO Oxidation by O2

“…This parallels ap revious study that after the replacement of an Au atom by Hi nA u 8 cluster with closed-shell electronic structure,the O 2 activation capability of the resulting Au 7 Hi si ncreased because of charge redistribution. [30] Direct O 2 activation starting from the Cu site has to surmount positive barriers of at least 0.20 eV (Supporting Information, Figure S17). This highlights the importance of the Al 4 O 5 region that participates directly in chemical reaction through charge transfer interaction, similar to that of Au/TiO 2 catalyst.…”

Noble‐Metal‐Free Single‐Atom Catalysts CuAl4O7–9− for CO Oxidation by O2

“…This is attributed to the difference of electronegativity between Cu (1.90) and Al (1.61), thus electrons prefer to accumulate on the CuO 2 region. This parallels a previous study that after the replacement of an Au atom by H in Au 8 cluster with closed‐shell electronic structure, the O 2 activation capability of the resulting Au 7 H is increased because of charge redistribution . Direct O 2 activation starting from the Cu site has to surmount positive barriers of at least 0.20 eV (Supporting Information, Figure S17).…”