Oxygen adsorption on Au/Al2O3 catalysts and relation to the catalytic oxidation of ethylene glycol to glycolic acid

Hydrotalcite‐Supported Gold Catalyst for the Oxidant‐Free Dehydrogenation of Benzyl Alcohol: Studies on Support and Gold Size Effects

“…We also measured the dispersion of Au over the Au/HT catalysts by H 2 -O 2 titration. [37] The Au dispersion obtained from the H 2 -O 2 titration decreased with increasing HAuCl 4 concentration (see Table 2). Moreover, the values of Au dispersion evaluated from the H 2 -O 2 titration were quite close to those estimated from the Au size obtained by TEM.…”

Quantitative determination of sites able to chemisorb CO on Au/ZrO2 catalysts

“…Then the prepared Zr(OH) 4 was sulfated with (NH 4 ) 2 SO 4 (Merck) by incipient wetness impregnation (2.5 wt%SO 4 2À /ZrO 2 ) and finally heated (90 K/h) up to 923 K in flowing air (30 mL/min STP) and kept at this temperature for 6 h, followed by slow cooling to room temperature [8]. Gold was deposited on the calcined support by deposition precipitation (hereafter denoted as dp) with both constant and variable pH, using either a Na 2 CO 3 aqueous solution (1 M Table 1).…”

“…A technique more widely diffuse both in academic and industrial laboratories, reproducible and fast, such as chemisorption test, should be very useful for these systems. Unfortunately, as well known, gold does not chemisorb many molecules easily, and in fact there are only few scientific works related to characterization of supported gold by chemisorption methods [1][2][3][4][5]. We have recently shown [6] that CO chemisorption by a pulse flow technique and Fourier transform infrared measurements of adsorbed CO in well defined and controlled conditions of temperature and pressure can be taken as effective methods for the quantitative determination of the gold active sites on Au/TiO 2 and Au/Fe 2 O 3, two reference catalysts provided by the World Gold Council, and on a Au/CeO 2 sample.…”

Surface chemistry of catalysis by gold

“…We have previously discussed size effects in gold catalysis, which arise either from electronic effects, structural effects or a combination thereof. In spite of the data found in both the catalytic and surface science communities, particularly the dramatic results from size selected clusters, many experiments involving real catalysts report that size effects are not a critical factor in determining activity (365,403,419,420). We are therefore left to question what the controlling factors for CO oxidation really are.…”