Influence of Si/Al ratio of MOR type zeolites for bifunctional catalysts specific to the one-pass synthesis of lower olefins via CO2 hydrogenation

Selective CO2hydrogenation over zeolite-based catalysts for targeted high-value products

“…196,197 However, the coke formation rates increased with the increasing BASs density of 8-membered rings, 194,196 which were 0.02, 0.03, and 0.08 (mg coke ·μmol acid −1 h −1 ) for MOR(Si/Al = 9)/ZnZr, MOR(Si/Al = 14)/ZnZr, and MOR(Si/Al = 104)/ZnZr, respectively. 194…”

“…This is supported by Alberti's studies, 195 which concluded the BASs over MOR zeolite with high Si/Al ratio were near 8-membered rings, and the acid sites in 8-membered rings promoted the MTO reaction. 196,197 However, the coke formation rates increased with the increasing BASs density of 8-membered rings, 194,196 which were 0.02, 0.03, and 0.08 (mg coke $mmol acid −1 h −1 ) for MOR(Si/Al = 9)/ZnZr, MOR(Si/Al = 14)/ZnZr, and MOR(Si/Al = 104)/ZnZr, respectively. 194 Bonura 45,187 investigated the inuence of acid sites on the activity and stability of hybrid catalysts during the dimethyl ether (DME) production via CO 2 hydrogenation over Cu-ZnO-ZrO 2 (CZZ) and zeolites.…”

“…196,197 However, the coke formation rates increased with the increasing BASs density of 8-membered rings, 194,196 which were 0.02, 0.03, and 0.08 (mg coke $mmol acid −1 h −1 ) for MOR(Si/Al = 9)/ZnZr, MOR(Si/Al = 14)/ZnZr, and MOR(Si/Al = 104)/ZnZr, respectively. 194 Bonura 45,187 investigated the inuence of acid sites on the activity and stability of hybrid catalysts during the dimethyl ether (DME) production via CO 2 hydrogenation over Cu-ZnO-ZrO 2 (CZZ) and zeolites. The CZZ/FER (Si/Al = 60), with a lower concentration of acid sites, exhibited a slightly higher DME selectivity (43.0%) compared to the highly acidic CZZ/FER (Si/Al = 8) (36.5%) in the reaction time of 1500 min, which was attributed to the higher deactivation rate over the high acidic FER zeolite as shown in Fig.…”

“…Similar results were also observed in Tada's studies. 194 ZnOZrO 2 and MOR zeolite with varied Si/Al ratios were employed for the hydrogenation of CO 2 to short chain olefins. The MOR-based catalyst with a high Si/Al ratio (104) exhibited the highest olefin (C 2 –C 5 ) selectivity (21.1%) compared to that of ZnZr/MOR (Si/Al = 9) (11.4%) and ZnZr/MOR (Si/Al = 14) (17.4%), which was attributed to its higher concentration of BASs in the 8-membered rings.…”

Selective Valorization of CO2 towards Valuable Hydrocarbons through Methanol‐mediated Tandem Catalysis

“…Specifically, the density of BAS can be decreased by decreasing the Al content of the zeolite [71,95,98] . Lower acid site density can reduce secondary hydrogenation events during MTO, enhancing olefin selectivity [98–99] …”