Organic-free synthesis of MOR nanoassemblies with excellent DME carbonylation performance

Recent advances in the routes and catalysts for ethanol synthesis from syngas

“…Common methods are acid or alkali treatment, steam or heat treatment, etc. 236,237,246 Zhou et al improved the performance of DME carbonylation over HMOR catalysts, by simple alkaline treatment. 236 A part of Si species and small amounts of Al species were removed out during the alkali treatment, leading to the formation of mesopores and macropores.…”

“…They are formed by the coordination of two or more inorganic oxyacids, and exhibit excellent catalytic activity. 237 Moreover, the HPAs with a spherical molecular surface possess a low charge density and high efficiency of proton transport. Therefore, the catalyst surface has a higher proton activity and more Bronsted acidity.…”

Insight into Crystallization Features of MOR Zeolite Synthesized via Ice-Templating Method

“…This conclusion is further proven through NH 3 -TPD analysis (Figure 11). It is clearly exhibited that the NH 3 desorption profiles for IW-MOR-24 and IN-MOR-24 samples show the significant shift to higher temperatures in comparison with the T-MOR-24, regardless of the low temperature peak (lower than 300 • C, corresponding to the weak acid center) and high temperature peak (greater than 400 • C, ascribed to the strong acid centers) [46,54]. Table 3.…”

“…It is generally accepted that the FTIR absorption spectra at around 3750 cm −1 and 3660 cm −1 is attributed to the terminal silanol groups on the external surface and the aluminol of extra-framework Al species, respectively [43][44][45][46]. Moreover, the signal located at 3620 cm −1 is considered to be the bridging hydroxyls, which are responsible for the strong Bronsted acidic (Si-OH-A1) sites [47][48][49][50].…”

“…It is indicated that there are more T-OH (T = Si, Al) groups and Si-OH-Al sites, which are closely related to an enhanced acid strength [51][52][53]. Furthermore, the bonding environment of the silicon atoms in the zeolite framework was recorded by the solid-state 29 Si MAS NMR spectrum, and the spectrum resonances centered at around −113, −106 and −100 ppm are ascribed to Si(0Al), Si(1Al) and Si(2Al) structure types, respectively [46]. The relative decrease in the tetrahedrally coordinated Si(0Al) is confirmed (Q4) (Figure 10 and Table 3).…”