Relation between nanoscale Au particle structure and activity for CO oxidation on supported gold catalysts

Abstract

The CO oxidation activity of a

Insights into the reactivity of supported Au nanoparticles: combining theory and experiments

“…For this reaction, the general trend is that supported gold catalysts, which exhibit significant catalytic activity, always contain gold particles with a diameter less than approximately 5-6 nm, as Haruta et al pointed out already in an early publication [5]. This is illustrated in figure 2, showing a compilation of literature data from the past 10 years for CO oxidation activities at 273 K as a function of the Au particle diameter for different Au catalysts [13,22,43,47,54,55,[89][90][91][92][93][94]. The strong dependence of the activity on the Au particle size is obvious.…”

“…This is clear experimental evidence that the gold particle size is an important parameter for the catalytic activity of supported catalysts. In order to gain some insight into the reason for this particle size effect, we Reported catalytic activities (in mmol/g Au s, left axis) for CO oxidation at 273 K over different Au-based catalysts as a function of the Au particle size (d, in nm) [13,22,43,47,54,55,[89][90][91][92][93][94]. The different supports are indicated by the symbol shape, open symbols correspond to reducible supports, closed symbols to irreducible supports.…”

“…This has been done for a supported Au/TiO 2 , Au/MgAl 2 O 4 and a Au/Al 2 O 3 catalyst, all containing approximately 4 wt% Au [47]. The activity of these three catalysts was measured at 273 K and 1 atm, using a feed of 1% CO and 21% O 2 in Ar, after annealing the freshly prepared catalysts for 1 h at 400°C in the same gas mixture.…”

“…The first type of explanations associates the catalytic activity with the nature of the gold atoms in the particles. Both theory and experiments have pointed to the importance of lowcoordinated Au atoms acting as active sites [35][36][37][38][39][40][41][42][43][44][45][46][47]. A change in the electronic structure of gold, resulting in a metal-insulator transition has also been invoked [6,[48][49][50].…”

Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol: Effect of Gold Particle Size on Activity and Selectivity in Different Solvents

“…It seems crucial for the elucidation of the particle size effect to employ only one preparation method as important variables such as impurities, remaining residues on the catalysts surface, and particle morphology might be altered by using different preparation techniques [7,14]. Also a change of the support [15] or a foreign atom [16] can affect the morphology of adsorbed Au particles which directly influences the binding energy of oxygen [17].…”