Ethylbenzene dehydrogenation over FeOx/(Mg,Zn)(Al)O catalysts derived from hydrotalcites: Role of MgO as basic sites

The properties and catalytic performance of PtSn/Mg(x-Ga)AlO catalysts for ethane dehydrogenation

“…3, all the catalysts exhibit a similar broad desorption shape consisting of three peaks at around 220 C, 320 C and 450 C. According to a previous study, the three tted peaks are regarded as weak, medium, and strong acid sites, respectively, which should be attributed to the Lewis acidity of the MgO-Al 2 O 3 mixed oxide. 44 From Table 2, it can be noticed that when a small quantity of Ga was added, the total acidity and the fraction of strong acid sites distinctly decreased. The PtSn/Mg(0.75-Ga)AlO catalyst exhibits the lowest total acidity and the PtSn/Mg(2-Ga) AlO catalyst possesses the lowest fraction of strong acid sites.…”

The influences of Mg/Al molar ratio on the properties of PtIn/Mg(Al)O- x catalysts for propane dehydrogenation reaction

“…As can be seen from Fig. 5, all the samples exhibit three fitted peaks at 180-200°C, 200-350°C and around 500°C, which can be ascribed to the surface sites of weak (OH À groups), medium (Mg 2+ -O 2À pairs) and strong (isolated O 2À anions) basicity of Mg(Al)O-x respectively [52]. From Table 3, it can be seen that the fraction of weak and medium basicity increases as Mg/Al ratio increases.…”

“…Moreover, the highest total basicity is observed over PtIn/Mg(Al)O-4 catalyst, and the value decreases with further increase of Mg/Al ratio (low Al content). It can be explained that the formed surface amorphous AlO y structure in samples with low Al content (Mg/Al > 5) partially covered the Mg 2+ -O 2À pairs [52].…”

Optimum ratio of K2O to CeO2 in a wet-chemical method prepared catalysts for ethylbenzene dehydrogenation

“…Significantly, the combined action of Fe 3+ and Ce 3+ plays a positive role in EBDH: during EBDH reaction, α-hydrogen of ethylbenzene attacks the acid site of the catalysts (Fe 3+ ) and simultaneously, β-hydrogen attacks the basic site (Ce 3+ ), as shown in Fig. S2 [10,18,19], while positive charge on α-carbon at the transition state can be stabilized by the aromatic ring. Based on the point of view mentioned above, K/Ce-1.40 and K/Ce-1.12 catalysts may have better catalytic activity, because their relatively high CeO 2 content is beneficial for the keeping of Fe 3+ (instead of being reduced to Fe 2+ ) and the coexisting of Fe 3+ and Ce 3+ .…”