Gold based catalysts on ceria and ceria-alumina for WGS reaction (WGS Gold catalysts)

Abstract

Gold catalysts supported on ceria-alumina have been studied in WGS reaction. A high and stable activity was established for the catalysts supported on ceria-alumina, prepared by mechanochemical activation in comparison to the corresponding samples, where ceria-alumina support was prepared by coprecipitation. The catalysts were characterized by means of XRD, TPR, Raman and XPS spectroscopy. A correlation between WGS activity and the redox activity was found. On the basis of the results obtained a model of the reaction mechanism and of active sites was proposed.

NO reduction by CO over gold catalysts based on ceria supports, prepared by mechanochemical activation, modified by Me3+ (Me = Al or lanthanides): Effect of water in the feed gas

“…It should be noted that the AuCeYb catalyst showed the highest activity in the WGS reaction among the gold catalysts supported on ceria doped by the other lanthanides [23]. Regarding the catalysts based on ceria-alumina (CP or MA with different alumina content), the AuCeAlMA (10 wt.% alumina) exhibited the highest WGS activity [22]. A relationship between the catalytic activity in the NO + CO reaction in the presence of water and catalytic activity in the WGS reaction has to be taken into consideration.…”

“…The loading of gold on ceria causes a strong modification, resulting in the creation of oxygen vacancies and Ce 3+ [22,30]. As the ionic radius of Ce 3+ (1.14 Å ) is larger than that of Ce 4+ (0.97 Å ), the generated Ce 3+ ions cause an increase of the lattice parameter a of ceria from 5.412 Å (undoped ceria) to 5.422 Å (AuCe sample).…”

“…The average size of gold particles on the AuCe catalyst and gold catalysts on ceria doped by the lanthanides was lower than the XRD limit to about 3 nm and it was estimated by HRTEM. The data obtained were: 2.0 nm for AuCe [15,22], 2.4 nm for AuCeSm and 2.3 nm for AuCeLa [23]. The BET surface area, lattice parameters and the average particle size of ceria, determined by XRD are presented in Table 1.…”

Gold stabilized aqueous sols immobilized on mesoporous CeO2–Al2O3 as catalysts for the preferential oxidation of carbon monoxide

“…The studies on catalytic systems based on gold nanoparticles supported on ceria and alumina-ceria were also extended to low temperature WGS [49,50], complete hydrocarbon oxidation and CO-PROX [12,13,15,16]. Gold-ceria catalysts were found to be very active and stable systems.…”

Performance of Au/M x Oy/TiO2 Catalysts in Water-Gas Shift Reaction

“…Gold catalysts for WGS include Au/TiO 2 [12][13][14], Au/TiO 2 /C [15,16], Au/Fe 2 O 3 [17][18][19][20][21][22][23], Au/Fe 2 O 3 -ZrO 2 [24], Au-Ru/Fe 2 O 3 [25,26], Au/CeO 2 [27][28][29][30][31][32][33][34][35][36][37], Au/CeO 2 -Al 2 O 3 [38,39], Au/La-CeO 2 [40][41][42][43], Au/Gd-CeO 2 [44], Au/CeO 2 -ZrO 2 [45][46][47], Au/ZrO 2 [48][49][50], Au/ThO 2 [51], Au/Ca 10 (PO 4 ) 6 (OH) 2 [52], and Au/zeolites [53]. Nevertheless, there is still a need for searching for highly efficient gold catalysts for WGS.…”