Sequential and/or Simultaneous Wet‐Impregnation Impact on the Mesoporous Pt/Sn/Zn/γ‐Al₂O₃ Catalysts for the Direct Ethane Dehydrogenation

Abstract

This study is aimed at investigating the impact of catalyst preparation’s approach (either sequential and/or simultaneous wet impregnation) to a mesoporous series of Pt/A, Sn/A, PtSn/A, SnPt/A, (PtSn)/A, (PtSn)Zn/A, and (PtSnZn)/A catalysts for direct ethane dehydrogenation. The (PtSn)/A and (PtSnZn)/A had shown both higher initial specific activity (s-1) and reaction rate constant K d (h-1) (13063.86 (s-1) and 12489.69 (s-1) and 0.09 (h-1) and 0.06 (h-1)), respectively. The catalyst preparation approach had direct impact to the availability and dispersion of mesoporous particles of either active metal and/or promoter that influences either to hinder the C-C cleavage and/or to promote C-H bond cleavage in the dehydrogenation of ethane to ethene. The active metal component was present in the form of Pt, Pt+2, Al+3, Sn+4, and Zn+2 states. The enhanced catalytic activity is attributed to the Pt4Sn and PtZn formed phases in addition to highly dispersed mesoporous Pt particles. Based on the obtained results, the catalysts prepared by using simultaneous wet impregnation had shown higher catalytic activity and catalyst stability as to that of sequential wet impregnation.

Porous Single‐crystalline Centimeter‐sized α‐Al2O3Monoliths for Selective and Durable Non‐oxidative Dehydrogenation of Ethane

“…Based on the first‐order for deactivation and the surface reaction kinetics, which the deactivation constants (k d ) are obtained [25–27] . The stability of the reduced PSC α‐Al 2 O 3 monoliths is unprecedented as shown in Figure 4f and Table S3–S4 [17,19–24,28–31] . We compare the present results with ethane dehydrogenation over PtSn alloy, Cr‐O x and other catalysts.…”

“…The ethylene selectivity generally reaches over 95 % with porous single crystals, which is comparable to the ethylene selectivity in thermal cracking in control experiment. The catalytic performances of PSC α‐Al 2 O 3‐x are outstanding in the reported alumina‐based catalysts in the ethane dehydrogenation reaction [16–21,28–31] . Here, the unsaturated metal‐oxygen coordination structures at the surface in porous single crystals are believed to be the active sites for ethane dehydrogenation.…”

“…[25][26][27] The stability of the reduced PSC α-Al 2 O 3 monoliths is unprecedented as shown in Figure 4f and Table S3-S4. [17,[19][20][21][22][23][24][28][29][30][31] We compare the present results with ethane dehydrogenation over PtSn alloy, Cr-O x and other catalysts. Although the ethane conversion is high at lower temperatures, the ethylene selectivity and catalyst durability are still facing challenges.…”

Highly Efficient PtSn/Al2O3 and PtSnZnCa/Al2O3 Catalysts for Ethane Dehydrogenation: Influence of Catalyst Pretreatment Atmosphere

“…The endothermic ethane dehydrogenation reaction (EDH) reaction is equilibrium limited; thus, attaining a high degree of conversion requires high reaction temperatures. At these reaction conditions, an intensive coke formation on the catalyst surface takes place, and fast catalyst deactivation is observed [18,39]. Among the three PtSn catalysts calcined in three different atmospheres, PtSn-SA exhibits the highest ethane conversion, whereas the PtSn-N 2 catalyst displays the lowest ethane conversion.…”

“…Hence, the stability of the supported Pt active phase structure is crucial for discovering the activity and stability of the ethane dehydrogenation (EDH) reaction at higher temperatures. The addition of promoter metals, like Sn, In, Ga, Ir, Cu, or Au, to Pt-based catalysts has been shown to increase selectivity by stabilizing Pt particles [11][12][13][14][15][16][17][18]. The addition of promoter metals like tin to platinum weakens the bond between the ethene and the catalyst surface.…”