Platinum promoting effects in Pt/Ga zeolite Catalysts of lower alkane aromatization. I. Ga and Pt electronic states, dispersion and distribution in zeolite crystals in dependence of preparation techniques. Dynamic effects caused by reaction mixture

Metal oxide catalysts for DME steam reforming: Ga2O3 and Ga2O3–Al2O3 catalysts with and without copper

“…However, it could be noted that similar types of changes and redispersion of gallium were earlier observed with the Ga-containing system [31,44]. The redistribution of Cu on the Cu-Zn/Ga 2 O 3 and Cu-Zn-Ga 2 O 3 /SiO 2 catalyst systems has recently been studied by Fierro's group for the catalytic conversion of CO 2 to methanol [45].…”

“…As for the Gacontaining system, the redispersion of Ga 2 O 3 species during the reduction process modifies the acidic properties of the system and the catalytic activity and stability. It has been reported that the loading of gallium ion induced strong Lewis acid sites in ZSM-5 [31]. During the reaction process such an effect would be possible: it would enhance the activity and stability of the catalyst during the course of the reaction.…”

“…reported for Cu 0 (931.8-932.8 eV) [23][24][25][26][27], Ga 3+ (1117.5-1118.3 eV) [28][29][30][31] and Al 3+ (73.3-74.5 eV) [32][33][34][35]. It is noted that the XPS peak resulting from Ga 3d is not reliable for both the qualitative and quantitative analyses, due to the partial overlap of this peak with the O 2s peak that leads to a distorted shape [31]. Recording the Ga 2p 3/2 lines, which significantly differ in kinetic energy (KE), allows one to estimate the Ga concentration in the top surface areas and to non-destructively obtain a concentration profile [36].…”

Selective Production of 2-Phenylhexane from Benzene and n-Hexane Over Pt- and Ga-Modified Zeolites

“…We suggest that the close proximity of very small Pt nanoparticles to framework Ga-(OH)-Si acid sites (in the micropores of ZSM-5) is the reason for this very high selectivity to 2-phenylhexane over Pt/H-Ga f ZSM5. Similar synergetic effects of Pt and Ga were suggested to be responsible for the enhanced selectivity in alkane aromatization [28,29], steam reforming and dehydrogenation of methanol [30], dehydroizomerization of n-butane [31], hydrodechlorination of CCl 4 [32], and alkylation of benzene with propane [33]. Pt maintains a very low olefin concentration, suppressing cracking, while the close proximity of Pt to Ga-(OH)-Si is essential for the alkylation of benzene with the olefin intermediate.…”

Effect of support on the activity of Ga2O3 species for steam reforming of dimethyl ether

“…5a. The XPS peak resulting from Ga 3d is not reliable for both the qualitative and quantitative analyses due to the overlap of this peak with the O 2s peak, which leads to a distorted shape [9]. However, the Ga 2p 3/2 lines, which are quite different in binding energy (BE) around 1118 eV, allow the estimation of Ga concentration on the catalyst surface without any ambiguity [10].…”