Gold supported on pillared clays for CO oxidation reaction: Effect of the clay aggregate size

A series of 1% m/m gold particles supported on Fe, Ce and Al pillared bentonite (from Valle del Cauca, Colombia) and clay “M64” (from Tolima, Colombia) using three different fractions of aggregate sizes (≤ 2 μm, ≤ 50 μm, and ≤ 150 μm) were characterized by particle size measurements, X-ray diffraction, transmission electronic microscopy (TEM), SBET and X-ray fluorescence spectrometry (XRF) techniques. The materials tested with CO oxidation. The separation yield for each fraction depended on the type of clay. Whatever the clay or the aggregate size, the pillaring process was successfully carried out, introducing Fe, Ce and Al pillars and increasing the microporosity and the specific surface area of the material. Gold particles presented a homogenous distribution of 2–3 nm on the pillared bentonite, and of about 10 nm on the pillared clay M64. The aggregate size slightly influenced the amount of deposited gold particles and their size. All gold catalysts were active in CO oxidation, the activity depending on the nature of the clay as well as the gold loading and average gold particle size but not on the aggregate size.

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► Gold (1%) was deposited in 3 different aggregate sizes of two pillared smectites.
► Whatever the clay or the aggregate size, the pillaring process is successful.
► A homogenous distribution of Au is obtained, size depending on the clay nature.
► All synthesized gold catalysts are active solids in the CO oxidation reaction.
► Differences in activity can be explained by differences in the gold particle size.