Positively Charged Au Clusters

Cationic gold species have also been speculated as well as detected in-situ for various different reactions. The unique reactivity of cationic Au clusters supported on ceria has been suggested to be important in catalyzing the water gas shift (WGS) reaction. Fu et al. deposited small Au clusters on an La-doped reducible CeOg substrate and demonstrated unique, highly reactive Au particles for WGS. The surface was subsequently washed with a basic NaCN solution in order to leach out metallic Au. Despite the removal of metallic Au, the WGS activity over these leached systems remained the same, suggesting that the active catalytic sites were comprised of cationic gold. 

Others have speculated that cationic Au along with metallic Au must be present 1. Hydroxylated Au+ species can form at the periphery of the Au/oxide interface and may be the active species. 

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