Dynamics of Pd Dopant Atoms inside Au Nanoclusters during Catalytic CO Oxidation

Abstract

Doping gold nanoclusters with palladium has been reported to increase their catalytic activity and stability. PdAu 24 nanoclusters, with the Pd dopant atom located at the center of the Au cluster core, were supported on titania and applied in catalytic CO oxidation, showing significantly higher activity than supported monometallic Au 25 nanoclusters. After pretreatment, operando DRIFTS spectroscopy detected CO adsorbed on Pd during CO oxidation, indicating migration of the Pd dopant atom from the Au cluster core to the cluster surface. Increasing the number of Pd dopant atoms in the Au structure led to incorporation of Pd mostly in the S–(M–S) n protecting staples, as evidenced by in situ XAFS. A combination of oxidative and reductive thermal pretreatment resulted in the formation of isolated Pd surface sites within the Au surface. The combined analysis of in situ XAFS, operando DRIFTS, and ex situ XPS thus revealed the structural evolution of bimetallic PdAu nanoclusters, yielding a Pd single-site catalyst of 2.7 nm average particle size with improved CO oxidation activity.

Contributions of Internal Atoms of Atomically Precise Metal Nanoclusters to Catalytic Performances

“…It has thus far been elusive to decide which atom(s) on the surface or even internal of a catalyst can be capable of inducing a catalytic reaction. Atomically precise Au n nanoclusters hold great promise in serving as a unique class of model catalysts for gaining insight into the critical effects of internal atoms of the nanocluster catalysts on the catalytic behaviors [39–41] . Here, we highlight our recent work on the significant roles of internal atoms of atomically precise nanoclusters in manipulating the catalytic properties, which is different from other recent reviews on ligand‐protected nanoclusters [42–46] .…”

Toward the creation of high-performance heterogeneous catalysts by controlled ligand desorption from atomically precise metal nanoclusters

“…2C and O). 26,33,172 335 In their study, the Pd position within the metal NCs was tracked by operando diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS), and the results also showed that Pd migrates from the center of the metal core to the surface of the metal core during calcination (Fig. 37C).…”

“…Note that the absolute intensities of different samples cannot be compared. Reproduced with permission from ref 335…”

Recent Manganese Oxide Octahedral Molecular Sieves (OMS–2) with Isomorphically Substituted Cationic Dopants and Their Catalytic Applications

“…However, the fact that numerous catalysts involved in this procedure usually contain supported noble metals, such as: Pt, Pd, Rh, Ru, Au, Ag, etc. [198][199][200][201][202], makes the process rather expensive. For this reason, investigations have focused on developing useful catalysts based on earth-abundant metal cations or non-expensive metals.…”